Everyday & Planning tools
Percentages, dates, units, cooking ratios, running pace, sleep, school grades, timers, and random picks.
Turn a birth date into an exact age in years, months, and days, with totals and a next-birthday countdown.
Convert tank dimensions in inches or centimeters to gallons and liters, with filled weight and common tank presets.
Calculate BMI from metric or imperial height and weight, see the WHO category, and the healthy weight range for your height.
Estimate BMR and daily maintenance calories with the Mifflin-St Jeor equation, plus loss and gain targets.
Flip up to 100 virtual coins at once with a running heads/tails tally, percentages, and streak tracking.
Set hours, minutes, and seconds or a quick preset; get a big countdown, a progress bar, a tab-title timer, and a beep at zero.
Count the days between two dates — total, weekdays-only, and a Y/M/D breakdown — or add and subtract days from a date.
Roll any combination of standard dice with modifiers, type notation like 3d6+2, and keep a roll history.
Compute a package's dimensional weight from its size and divisor, and see whether dim or actual weight gets billed.
Add courses with credits and letter grades to compute a credit-weighted GPA, with an editable 4.0 grade scale.
Track a weighted course grade from assignment scores and solve what you need on the final to hit a target.
Work out running pace, finish time, or distance from the other two, in km or miles, with splits, negative splits, and Riegel race-time predictions.
Work out how many boxes fit a pallet: best 90° orientation per layer, layer count, total boxes, and volume utilization.
Solve the three everyday percent questions — X% of Y, X as a percent of Y, and percent change — side by side with live results.
Calculate swimming pool volume in gallons and liters for rectangular, round, and oval pools with constant or sloped depth.
Estimate how long a propane tank lasts for your grill, heater, or generator, and what each hour of use costs.
Generate random numbers in any range using the browser's crypto source, with no-repeat and sort options.
Estimate total fabric yardage from your pattern pieces, bolt width, layout efficiency, and pattern repeat allowance.
Find when to go to bed for a wake-up time, or when to wake for a bedtime, in whole 90-minute sleep cycles, with recommended sleep hours by age.
A timestamp-accurate online stopwatch with start, stop, lap, and reset, plus a lap table with splits and totals.
Enter clock-in and clock-out times for the week to total hours in h:mm and decimal, with breaks, overnight shifts, FLSA or California overtime, and pay.
Convert a date and time from one time zone to many at once, with UTC offsets and day-change badges.
Convert between units of length, weight, temperature, area, volume, speed, time, storage, energy, and pressure with a common-values table.
About Everyday & Planning tools
This is the site's everyday drawer — twenty small calculators that answer the questions that come up in ordinary life. Percentages solved three ways side by side, exact ages and date differences (including weekdays-only counts), unit conversion across length, weight, temperature, and seven other quantities, and a time zone converter that shows one moment across many zones with day-change badges. A stopwatch and a countdown timer cover timing, with the countdown visible right in the browser tab title.
There's a cluster for randomness — a crypto-backed random number generator, dice rolling with 3d6+2 notation, and coin flips with streak tracking — and clusters for health (BMI with WHO categories, calorie needs via the Mifflin-St Jeor equation, bedtimes and wake-up times by sleep cycle, and running pace with splits and race-time predictions) and school (credit-weighted GPA, and a grade tracker that solves what you need on the final to hit your target). More specialized entries compute pool and aquarium volumes, sewing fabric yardage, propane usage, dimensional shipping weight, and how many boxes fit on a pallet.
None of it requires an account or sends your numbers anywhere — each calculator loads instantly, runs in your browser, and works offline once the page is open.