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Understand how aperture, shutter speed, and ISO trade brightness for depth, motion, and noise—then test every decision in a live simulator.
PH-0002 · photography · conceptAperture and Depth of FieldSee what f-stops really change, why subject distance matters as much as aperture, and how to choose depth of field without memorizing a recipe.
PH-0003 · photography · conceptShutter Speed: Freezing and Blurring MotionChoose shutter speed by the motion you want to render, with practical starting points for people, sports, panning, handheld work, and long exposure.
PH-0004 · photography · conceptISO and Image NoiseLearn what digital ISO changes, why underexposure often looks noisy, when Auto ISO protects the photograph, and how to judge noise at output size.
PH-0005 · photography · troubleshootWhy Are My Photos Blurry?Diagnose blurry photos by visible evidence—camera shake, subject motion, missed focus, or optical softness—then run a 30-second test and fix the cause.
PH-0006 · photography · compareLightroom vs Capture OneCompare Lightroom and Capture One by cataloging, tethering, layered control, mobile workflow, licensing, and real use cases—with a transparent decision tool.
HS-0001 · home-systems · troubleshootWhy Is My Air Conditioner Not Cooling?Check thermostat settings, airflow, and the pattern of poor cooling. Learn what you can observe safely and when to stop and call a technician.
HS-0002 · home-systems · troubleshootThermostat Not Reaching the Set TemperatureCompare the set temperature, room reading, runtime, and airflow before replacing a thermostat. Separate a control problem from a heating or cooling problem.
HS-0003 · home-systems · conceptIndoor Humidity and Dew PointUnderstand relative humidity, temperature, and dew point together. Calculate dew point and identify moisture sources before buying humidity-control equipment.
HS-0004 · home-systems · calculateCooling BTU Estimate: A Screening GuideEstimate room AC capacity from floor area, sunlight, height, and occupancy. Understand why room sizing is not a whole-home HVAC load calculation.
HS-0005 · home-systems · troubleshootWhy Does My Furnace Short Cycle?Record short heating cycles, visible airflow restrictions, and error indicators. Know when a repeated shutdown needs professional service rather than another reset.
HS-0006 · home-systems · troubleshootWhy Is My Electric Bill So High?Compare billing days, daily kWh, and effective prices with an interactive bill checker. Find out what changed before blaming an appliance.
HS-0007 · home-systems · calculateHow to Calculate Appliance Electricity CostWork out running cost from watts, runtime, and your electricity price. See examples and learn why cycling appliances need a measured average.
HS-0008 · home-systems · conceptKilowatts vs Kilowatt-HoursLearn the difference between power and energy with worked examples. Translate watts and operating hours into the kWh shown on an electric bill.
HS-0009 · home-systems · conceptStandby Power: Measure Before You Chase ItEstimate annual standby electricity cost from measured watts. Compare likely savings with the effort and cost of switching equipment off.
HS-0010 · home-systems · calculatePaint Estimate by Wall Area and CoatsCalculate paint needs using net wall area, coat count, and product coverage. Account for openings and round purchases to available container sizes.
HS-0011 · home-systems · calculateFlooring Estimate with Waste and Package RoundingEstimate flooring purchases from room area, layout waste, and coverage per box. Keep material quantities separate from installation decisions.
HS-0012 · home-systems · calculateTile Coverage, Layout, and WastePlan tile quantity from surface area, layout, waste, and box coverage. Understand what a quantity estimate cannot tell you about installation.
HS-0013 · home-systems · calculateDrywall Sheet EstimateConvert wall and ceiling area into a drywall sheet estimate. Allow for cuts and keep fire-rating, moisture, and hazardous-material questions separate.
HS-0014 · home-systems · troubleshootRefrigerator Not Cooling: Safe TriageProtect food first, then inspect settings, door seals, and visible airflow. Record refrigerator symptoms before requesting service.
HS-0015 · home-systems · troubleshootWasher Not Draining: Safe ChecksIdentify the cycle state, visible hose problems, and error messages. Know when standing water or an internal fault needs service.
HS-0016 · home-systems · troubleshootDishwasher Not Cleaning: Diagnose the PatternDistinguish food residue from film, then check loading, accessible spray paths, and detergent conditions before assuming a failed part.
HS-0017 · home-systems · conceptU.S. Electricity Prices by State: Use the Right NumberFind official state electricity price data and distinguish averages from your tariff. Choose a rate that matches your bill or appliance-cost question.
HS-0018 · home-systems · checklistPower Outage and Portable Generator SafetyReview carbon monoxide and backfeeding hazards before planning outage loads. Separate essential running watts from startup requirements.
HS-0019 · home-systems · checklistHow to Keep Pipes From FreezingFind vulnerable pipes, prepare for cold weather, and recognize a possible freeze. Understand when to stop and get help with thawing or leaks.
HS-0020 · home-systems · checklistDIY Home Energy Audit: A Safe Walk-ThroughReview bills, visible drafts, insulation clues, and equipment schedules. Build a prioritized observation log and know when a professional audit is needed.
HS-0021 · home-systems · conceptWhere Home Energy Goes: Find the Biggest LoadsUse power, runtime, and seasonality to identify large household loads. Replace generic appliance rankings with your own electricity-use evidence.
HS-0022 · home-systems · conceptHow to Read an Electric BillSeparate energy use, billing days, supply, delivery, and fixed charges. Find the right numbers for a cost calculation without uploading your bill.
HS-0023 · home-systems · troubleshootWhy Is There No Hot Water?Separate a single-fixture problem from a whole-home outage or limited hot-water capacity. Identify observations to give a qualified repair professional.
HS-0024 · home-systems · conceptWater Heater Temperature: Scalds, Bacteria, and SavingsUnderstand storage and tap temperatures, scald risk, and bacterial control. Learn why one thermostat setting is not a universal safety answer.
HS-0025 · home-systems · troubleshootWhy Is My Water Pressure Low?Separate restricted flow from low supply pressure. Compare fixtures, check accessible restrictions, and collect useful information before a plumbing call.
HS-0026 · home-systems · troubleshootThe Running Toilet and the Silent LeakRun the ten-minute dye test, read what the sound tells you, and fix the flapper or fill valve before a silent leak quietly doubles a water bill.
HS-0027 · home-systems · checklistFind a Hidden Water Leak With the Meter TestTurn a suspicious water bill into evidence: run the meter test, isolate inside from outside at the main valve, and check the places leaks hide first.
CT-0001 · consumer-tech · troubleshootWhy Is My Wi-Fi Slow?Separate an internet-plan problem from Wi-Fi coverage, interference, congestion, and one-device faults with a repeatable sequence of tests.
CT-0002 · consumer-tech · compareMesh Wi-Fi vs. Range ExtenderCompare mesh systems, range extenders, and wired access points by backhaul, roaming, placement, setup complexity, and the shape of the home.
CT-0003 · consumer-tech · concept2.4 GHz vs. 5 GHz vs. 6 GHz Wi-FiUnderstand how Wi-Fi bands trade range, channel availability, interference, throughput, and device compatibility without treating frequency as speed.
CT-0004 · consumer-tech · conceptRouter Placement and Signal ObstaclesPlace a router by measuring the real radio path through rooms, floors, metal, masonry, cabinets, and competing electronics instead of guessing.
CT-0005 · consumer-tech · calculateMbps, Bandwidth, and Download TimeConvert megabits into file download time while keeping bits, bytes, decimal and binary units, protocol overhead, and server limits explicit.
CT-0006 · consumer-tech · calculateHow Much Storage Do I Need?Plan device or drive capacity from current data, photo and video assumptions, working headroom, growth, and the number of independent copies.
CT-0007 · consumer-tech · conceptThe 3-2-1 Backup MethodTurn the familiar three-copy, two-media, one-offsite convention into a testable personal backup system that survives deletion and ransomware.
CT-0008 · consumer-tech · conceptPhoto and Video File Size, ExplainedEstimate storage and transfer needs from resolution, compression, bit depth, frame rate, bitrate, duration, and decimal versus binary units.
CT-0009 · consumer-tech · compareSSD vs. HDD for Storage and BackupChoose solid-state or hard-disk storage by workload, capacity, shock exposure, performance, failure mode, sanitization, and backup role.
CT-0010 · consumer-tech · conceptWhat Can a USB-C Port Actually Do?Decode a USB-C connection by separating connector shape from data protocol, charging power, video mode, cable rating, dock, and host support.
CT-0011 · consumer-tech · conceptHDMI Versions Without the Marketing ConfusionMatch source, cable, receiver, and display by required resolution, refresh rate, HDR, VRR, and audio features instead of chasing version labels.
CT-0012 · consumer-tech · conceptResolution, Pixel Density, and Viewing DistanceConnect pixel dimensions, physical screen size, pixels per inch, viewing distance, interface bandwidth, and scaling without eye-limit myths.
CT-0013 · consumer-tech · compareChoosing Monitor Size and ResolutionChoose a monitor from desk distance, usable workspace, pixel density, operating-system scaling, refresh needs, HDR evidence, and port limits.
CT-0014 · consumer-tech · troubleshootWhy Is My Computer Suddenly Slow?Diagnose new computer slowness from timing, startup load, storage pressure, updates, thermals, malware indicators, and one reproducible task.
CT-0015 · consumer-tech · troubleshootWhat Is Filling Up My Storage?Use built-in Windows and macOS storage views to identify large categories, clean supported temporary data, and protect system and personal files.
CT-0016 · consumer-tech · troubleshootWhy Does My Monitor Show No Signal?Trace a no-signal display from power and selected input through cable, port, dock, protocol, graphics output, and a known-good substitution.
CT-0017 · consumer-tech · troubleshootWhy Is My Phone Battery Draining So Fast?Read the battery usage screen as evidence, separate screen, signal, background, and battery-age drain, then confirm the real cause with short controlled tests.
CT-0018 · consumer-tech · conceptPhone Battery Health, ExplainedUnderstand what the battery health percentage measures, why lithium-ion capacity fades with cycles and heat, and when a battery replacement is the rational fix.
CT-0019 · consumer-tech · conceptPhone Charging Habits That Actually MatterSeparate charging folklore from measurable battery chemistry: what overnight charging, fast chargers, charge limits, and heat really do to a phone battery.
CT-0020 · consumer-tech · troubleshootWhy Is My Phone Getting Hot?Tell normal warmth from a real problem by matching heat to its trigger — charging, sun, heavy apps, or background loops — and know the signs that mean stop.
CT-0021 · consumer-tech · troubleshootWhy Does My Printer Say Offline?Separate a printer the computer cannot reach from one it is merely ignoring: power and network state, stale addresses, paused queues, and driver records.
CT-0022 · consumer-tech · troubleshootPrinter Not Printing: Isolate the Failed LinkTrace a job from the app through the queue, the driver, the connection, and the printer’s own panel so one substitution test names the broken link.
CT-0023 · consumer-tech · conceptConnecting a Printer to Wi-Fi and Keeping It ConnectedUnderstand why printers drop off Wi-Fi more than laptops do — 2.4 GHz-only radios, address changes, and sleep behavior — and set the network so it stays found.
CT-0024 · consumer-tech · troubleshootStreaks, Faded Prints, and Wrong ColorsMatch the visible defect to its cause — clogged nozzles, empty or bad cartridges, paper settings, or a worn drum — and run the built-in checks before buying ink.
CT-0025 · consumer-tech · compareInkjet vs. Laser for Home PrintingCompare inkjet and laser printers by what you print, how often, cost per page, idle behavior, and space, instead of by the headline price of the printer.
AI-0001 · ai-workflows · conceptGenerative AI: Models, Chatbots, Agents, and ToolsSeparate a generated suggestion from a tool action, then turn a small contact-form request into something you can inspect and verify.
AI-0002 · ai-workflows · checklistWrite an AI Task Brief with Clear Acceptance CriteriaReplace “improve this form” with a bounded goal, relevant context, allowed files, acceptance checks, and explicit reasons to stop and ask.
AI-0003 · ai-workflows · conceptTokens, Context, and Memory: What an Agent Can UseBuild a compact project handoff without confusing the current context, durable instructions, model training, and a summary of earlier work.
AI-0004 · ai-workflows · checklistVerify AI Output and Protect Project DataUse a claim ledger and a data boundary to decide what can be checked locally, what may be shared, and which actions require a separate approval.
AI-0005 · ai-workflows · checklistYour First Read-Only Project in Claude CodeChoose the current official setup for your environment, open a disposable project, and verify a read-only contact-form inspection before allowing edits.
AI-0006 · ai-workflows · checklistWrite a CLAUDE.md That Describes Your Actual ProjectTurn verified project facts into concise Claude Code instructions, keeping durable rules separate from one-off tasks and permission enforcement.
AI-0007 · ai-workflows · checklistClaude Code: Plan, Build, Then Review a Small ChangeImprove one contact-form behavior with a scoped plan, a failing acceptance check, a small patch, and an independent review of the resulting diff.
AI-0008 · ai-workflows · checklistClaude Code Extensions: Skills, Hooks, Subagents, and MCPChoose the smallest extension for a repeatable workflow, and identify what it can read, execute, or send before adding it to a project.
AI-0009 · ai-workflows · checklistYour First Read-Only Project in CodexIdentify your current Codex environment, inspect a disposable repository, and verify the returned file inventory before authorizing a modification.
AI-0010 · ai-workflows · checklistWrite AGENTS.md with Clear Directory BoundariesDescribe verified project facts, commands, and approval boundaries for Codex, then check how root and nested guidance apply to the next task.
AI-0011 · ai-workflows · compareCodex Local, Worktree, or Cloud: Choose the Right BoundarySeparate working-file isolation from security and hosted execution, then choose a workspace with an explicit plan for setup, review, and cleanup.
AI-0012 · ai-workflows · checklistCodex Skills, MCP, Subagents, and Scheduled TasksChoose reusable guidance, a connector, bounded delegation, or a scheduled check based on the task’s real need and the access each option requires.
AI-0013 · ai-workflows · checklistHand Off Work Between Claude Code and CodexTransfer a bounded project state with files, evidence, limitations, and a next action instead of assuming two agents share conversation history.
AI-0014 · ai-workflows · checklistCoordinate Parallel AI Agents Without File CollisionsSplit independent work with named file owners, dependency gates, a shared budget, and an integration review that catches cross-task assumptions.
AI-0015 · ai-workflows · checklistTest and Review AI-Generated Code Beyond “Tests Pass”Combine a regression check, diff inspection, browser behavior, and explicit limits so a passing command cannot hide an incomplete contact-form change.
AI-0016 · ai-workflows · conceptGPT-6 Astra Explained: Capabilities, Context, Pricing, and LimitsA source-checked field guide to GPT-6 Astra: what the API model supports, what one million tokens does not guarantee, and when its higher unit price may or may not be justified.
AI-0017 · ai-workflows · conceptMiniMax H3 Explained: Open-Source Video, Native Audio, and the Hosted GapUnderstand what MiniMax H3 accepts and produces, which system components are open source, and why “open source” does not mean the complete 2K workflow runs locally.
AI-0018 · ai-workflows · conceptHow to Choose an AI Model for Coding AgentsChoose a coding model with a task-shaped evaluation: repository reach, tool reliability, latency, cost per accepted change, and the evidence required before integration.
AI-0019 · ai-workflows · calculateThe Real Cost of Using AI APIs: Tokens, Caching, Tools, and RetriesTurn per-million-token prices into a realistic task budget that includes output, cache writes, long-context multipliers, tool calls, failed attempts, and human review.
AI-0020 · ai-workflows · checklistHow to Read AI Benchmark Claims Without Being MisledInspect the task, dataset, tool access, scoring method, cost, variance, and replication behind an AI benchmark before using a leaderboard to choose a model.
undefined · everyday · articleHow age is calculatedUnderstand calendar age, completed years, leap days, and why age in total days is a different answer.
undefined · everyday · articleHow sales tax changes a priceLearn the sales-tax formula, combined local rates, and the difference between tax-exclusive and tax-inclusive prices.
undefined · everyday · articleHourly pay to annual salaryConvert hourly pay to weekly, monthly, and annual gross pay while keeping hours and paid weeks visible.
undefined · everyday · articleHow GPA is calculatedUnderstand credit-weighted grade points, unweighted and weighted scales, and why school rules must be checked.
undefined · everyday · articleCooking measurement conversionsUse a compact U.S. volume chart, understand why weight is more reliable, and scale recipe quantities safely.
undefined · everyday · articleHow BMI is calculatedLearn the BMI formula in US and metric units, the CDC adult screening ranges, and what the number can and cannot tell you.
undefined · everyday · articleHow to count hours workedTurn start times, end times, breaks, and overnight shifts into payroll hours and understand why timesheets use decimal hours.
undefined · everyday · articleWhat is in a mortgage paymentSee how principal, interest, property tax, insurance, and HOA dues combine into a monthly payment, and which parts a calculator can honestly estimate.
undefined · everyday · articleFinal grade mathUnderstand weighted averages, solve for the final-exam score you need, and read a syllabus weighting scheme correctly.
undefined · everyday · articleAdding hours and minutesAdd time values correctly with base-60 carrying, convert totals to decimal hours, and avoid the classic timesheet mistakes.
undefined · everyday · articleSleep cycles and bedtime mathUnderstand the 90-minute sleep cycle average, how bedtime calculators count backward, and what the arithmetic can and cannot promise.
undefined · everyday · articleHow to measure square footageMeasure rooms accurately, break irregular floor plans into simple shapes, and turn area into a realistic material estimate.
undefined · everyday · articleHow calorie needs are estimatedSee what the Mifflin-St Jeor equation actually models, how activity factors scale resting energy, and where the estimate stops being useful.
undefined · everyday · articleHow much does a space heater cost to run?Estimate the electricity cost of a space heater from its wattage, runtime, billing rate, and real duty cycle.
undefined · everyday · articleHow much electricity does an air conditioner use?Estimate AC electricity use without confusing cooling capacity (BTU/h) with the electrical input that appears on your bill.
undefined · everyday · articleHow much electricity does a refrigerator use?Read a refrigerator energy label, separate annual estimates from momentary watts, and turn kWh into a defensible running cost.
undefined · everyday · articleHow to lower an electric bill in an apartmentUse a short, renter-friendly audit to find the biggest loads, verify the bill, and test one change at a time.
undefined · everyday · articleHow much water does a shower use?Estimate shower water use from flow rate and minutes, then compare a standard showerhead with a WaterSense-labeled model.
undefined · everyday · articleHow much does a leaky faucet cost?Measure a drip rate, turn it into gallons per day, and separate water volume from the local water and sewer charge.
TL-0001 · photography · toolExposure simulatorBalance aperture, shutter speed, and ISO while seeing how each choice changes depth, motion, and noise.
TL-0002 · photography · toolLightroom vs Capture One decision toolWeight cataloging, tethering, layers, mobile access, and cost to find the editor that fits your workflow.
HS-T01 · home-systems · toolCooling BTU estimatorScreen a room air-conditioner capacity range from area, ceiling height, sun exposure, and occupancy.
HS-T02 · home-systems · toolHumidity and dew point calculatorCalculate dew point and place an indoor relative-humidity reading in useful context.
HS-T03 · home-systems · toolAppliance energy cost calculatorCompare electricity costs for up to twelve appliances, model daily schedules, and estimate savings with your own rate.
HS-T04 · home-systems · toolRoom finish estimatorEstimate paint, flooring, tile, or drywall purchase units with explicit coverage, coats, and waste assumptions.
HS-T05 · home-systems · toolAppliance symptom triageTurn visible refrigerator, washer, or dishwasher symptoms into the next safe external check.
HS-T06 · home-systems · toolGenerator sizing calculatorScreen continuous and starting-watt capacity from the loads you plan to run, the largest startup surge, and visible headroom.
HS-T07 · home-systems · toolBattery runtime calculatorEstimate portable-power runtime from rated watt-hours, conversion efficiency, reserve, load, and duty cycle.
CT-T01 · consumer-tech · toolWi-Fi symptom diagnosisSeparate device, coverage, congestion, visibility, and upstream internet patterns with controlled follow-up tests.
CT-T02 · consumer-tech · toolBandwidth and download-time calculatorConvert file units and Mbps into a transparent download estimate with an explicit effective-rate assumption.
CT-T03 · consumer-tech · toolStorage capacity plannerPlan working photo and video data, independent copies, and headroom without hiding file-size assumptions.
CT-T04 · consumer-tech · toolFile transfer time calculatorEstimate copy time from decimal file size and observed sustained throughput rather than interface marketing speed.
CT-T05 · consumer-tech · toolMonitor PPI calculatorCalculate pixel density, physical panel dimensions, and pixels per degree from resolution, size, and viewing distance.
EV-T01 · everyday · toolPercentage calculatorCalculate a percentage, the share of a whole, or the signed percentage change between two values.
EV-T02 · everyday · toolDiscount calculatorFind the discount amount, sale price, optional sales tax, and final price before checkout.
EV-T03 · everyday · toolTip and bill split calculatorCalculate a tip, total bill, and equal per-person share without losing cents to guesswork.
EV-T04 · everyday · toolDate duration calculatorCount elapsed calendar days and weeks between two dates without daylight-saving-time drift.
EV-T05 · everyday · toolUnit converterConvert common length, mass, volume, and temperature units through transparent SI-based formulas.
EV-T06 · everyday · toolLoan payment calculatorEstimate fixed monthly principal-and-interest payments, total repayment, and total interest.
EV-T07 · everyday · toolCompound interest calculatorModel hypothetical compound growth with a starting amount and monthly contributions.
EV-T08 · everyday · toolFuel cost calculatorEstimate trip fuel use and cost with either MPG or litres per 100 kilometres.
EV-T09 · everyday · toolAge calculatorCalculate completed years, months, days, and total elapsed days on a chosen date.
EV-T10 · everyday · toolSales tax calculatorAdd a known sales-tax rate and separate the pre-tax price, tax amount, and checkout total.
EV-T11 · everyday · toolHourly to salary calculatorConvert an hourly rate into weekly, monthly, and annual gross pay using explicit schedule assumptions.
EV-T12 · everyday · toolGPA calculatorCalculate a credit-weighted grade point average using the scale supplied by your school.
EV-T13 · everyday · toolRecipe scalerResize an ingredient amount from the original yield to a new number of servings.
EV-T14 · everyday · toolBMI calculatorScreen adult body mass index in US or metric units with visible CDC category boundaries.
EV-T15 · everyday · toolHours worked calculatorCount hours between a start and end time, subtract unpaid breaks, and get payroll-ready decimal hours.
EV-T16 · everyday · toolMortgage payment calculatorEstimate a monthly mortgage payment with principal, interest, property tax, insurance, and HOA dues shown separately.
EV-T17 · everyday · toolFinal grade calculatorFind the score you need on a weighted final exam to reach your target course grade.
EV-T18 · everyday · toolTime calculatorAdd hours and minutes across up to four entries and convert the total into decimal hours.
EV-T19 · everyday · toolSleep calculatorWork backward from a wake-up time in 90-minute sleep cycles to compare candidate bedtimes.
EV-T20 · everyday · toolSquare footage calculatorCalculate the area of a rectangle, circle, or triangle in feet and turn it into a material cost.
EV-T21 · everyday · toolCalorie calculatorEstimate resting and total daily calorie needs with the Mifflin-St Jeor equation and explicit activity factors.
AI-T01 · ai-workflows · toolAI Task Brief BuilderTurn your goal, scope, and acceptance criteria into a clear Markdown task brief locally in your browser.
AI-T02 · ai-workflows · toolAgent Instructions BuilderDraft AGENTS.md or CLAUDE.md from the project facts and boundaries you supply, without inventing commands.