50 Free Calculators & Utility Tools

Free TDEE calculator using Mifflin-St Jeor and Katch-McArdle. Get maintenance calories, a cutting target, protein/carb/fat grams and the exact date you hit your goal weight.

Estimate body fat percentage with the US Navy circumference formula. Enter neck, waist and hip measurements to get body fat %, lean mass, fat mass and Navy standard pass/fail.

Estimate your one rep max from any set of 1-12 reps using Epley, Brzycki and Lombardi formulas, plus a full percentage training chart for bench press, squat and deadlift.

Work out ketogenic net carbs, protein and fat grams from your daily calorie budget. Includes total vs net carb maths, fibre and sugar alcohol subtraction, and a keto tier table.

Project weight lost during a water fast, split into glycogen water, true fat loss and lean tissue. Includes autophagy timeline, refeed guidance and per-day loss table.

See how much caffeine is still in your bloodstream at bedtime. Enter your drink, the time you had it and your metabolism speed to get an hour-by-hour decay curve.

Enter current weight, goal weight and daily deficit to get the exact date you reach target, weekly milestone table and a plateau-adjusted realistic date.

Compare four clinical ideal body weight formulas side by side, adjusted for frame size, plus healthy BMI range and drug-dosing lean body weight.

Calculate all five training heart rate zones using the Karvonen heart rate reserve method, with fat-burn vs cardio comparison and a resting-HR fitness benchmark.

Calculate true dough hydration including the flour and water inside your starter, plus salt percentage, total dough weight and a hydration-to-crumb reference table.

Calculate your ideal creatine monohydrate loading and maintenance dose instantly. Free online creatine dosage calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate your estimated insulin to carb ratio and correction bolus instantly. Free online insulin to carb ratio calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate how much elemental magnesium you're actually getting instantly. Free online elemental magnesium calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate your estimated safe sun exposure time instantly. Free online UV index tanning calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate your ideal daily water intake instantly. Free online creatine water intake calculator with live formulas, unit conversion and a step-by-step breakdown.

Convert an hourly wage into weekly, bi-weekly, monthly and annual pay including overtime multipliers, paid time off and unpaid leave weeks.

Project your FIRE number, retirement age and Coast FIRE benchmark using your savings rate, expected return and safe withdrawal rate. Lean, Standard and Fat FIRE modes.

See principal, contributions and compound interest split year by year. Supports monthly deposits, any compounding frequency and a full growth table.

Work out the hourly rate you must charge as a freelancer once non-billable time, business expenses, self-employment tax and unpaid holidays are covered.

Split a restaurant bill evenly, add any tip percentage, handle pre-tax tipping and rounding, and see exactly what each person owes.

Split shared rent fairly using room area, private bathroom premium and shared space allocation. Produces a per-room monthly figure both housemates can accept.

Compare the snowball and avalanche debt payoff methods across up to four balances. See months to debt-free, total interest paid and which method wins for you.

See what money from any past year is worth today, how much purchasing power was lost, and the cumulative and annualised inflation rate between two years.

Strip out materials, platform fees, shipping and tax to find what your side hustle really pays per hour — and what price rise you need to hit a target wage.

See how much interest an extra monthly mortgage payment saves and how many years it removes from the term, with a side-by-side amortisation comparison.

Calculate net creator take-home instantly. Free online Substack vs Patreon fee calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate net shipping profit and true order margin instantly. Free online Etsy shipping margin calculator with live formulas, unit conversion and a step-by-step breakdown.

Work out what to charge for an Airbnb cleaning fee and see gross booking value, turnover cost, host net profit and net margin per stay in one calculation.

Calculate time-and-a-half and double-time overtime pay with tax withholding. See gross regular pay, overtime pay, holiday premium pay and net take-home in seconds.

Compare Stripe and PayPal payout after processing, international card and currency conversion fees. See exactly which processor leaves more money in your account.

Measure what returns really cost: returned order count, lost revenue, reverse-logistics spend and the net margin hit across a month of shipped orders.

Convert pawn shop or car title loan fees into a true annual percentage rate. See total finance charges, the periodic rate and the real APR behind a short-term loan.

Calculate the exact gap between two dates in years, months, days, total weeks, hours and minutes, with leap-year handling and business-day context.

Check any age gap against the half-your-age-plus-seven rule, see the socially acceptable dating range for both partners and the percentage age difference.

Find bedtimes and wake times that land at the end of a 90-minute sleep cycle, including fall-asleep latency, so you wake in light sleep instead of deep sleep.

Count down the exact days, weeks and hours to every milestone birthday from your date of birth, plus the weekday each milestone falls on.

Convert your dog's age to human years using size-adjusted veterinary tables rather than the outdated seven-year rule, plus life-stage and care guidance.

Convert cat age in months or years to human equivalent using AAFP feline life stages, with indoor versus outdoor life expectancy and senior care markers.

Find working-hour overlap between up to three time zones and get the meeting slots that are civil for everyone, with a full hour-by-hour comparison grid.

Count working days between two dates, excluding weekends and any number of custom public holidays, with a weekend-day and calendar-day breakdown.

Find the weekday of any birth date, when your birthday next repeats on that weekday, how many times it has fallen on each day, and your birth-date facts.

Calculate an IVF due date from the embryo transfer date and embryo stage, with gestational age today, trimester dates and key scan milestones.

Convert any width or height into the matching pixel dimensions for 16:9, 9:16, 1:1, 4:5 and 21:9, with safe-zone guidance for Reels, Shorts and TikTok.

Convert a word count into silent reading time, presentation speaking time and audiobook narration length, with WPM control and a speech-length reference table.

Calculate engagement rate by followers, by reach and by impressions, compare against platform benchmarks and estimate sponsored post value.

Calculate how long a file takes to download or upload at any connection speed, with real-world overhead applied and a speed comparison table.

Build a screen break schedule using the 20-20-20 rule, see total break minutes, blink deficit and a full daily timetable for your working hours.

Estimate YouTube earnings from daily views using niche CPM ranges, the 55% creator share, monetised playback rate and a full RPM comparison table.

Convert a word count into printed page count for any font size, line spacing and margin setting, with an academic and manuscript reference table.

Estimate monthly Twitch income from tier 1, 2 and 3 subscriptions, bits, ad revenue and the 50/50 or 70/30 split, with a payout threshold check.

Work out what any appliance costs to run per hour, day, month and year from its wattage and your electricity tariff, with standby cost and a wattage reference table.

Convert between bytes, KB, MB, GB, TB and PB in both decimal (1000) and binary (1024) bases, and see why a 1 TB drive shows as 931 GB.

Calculate net creator payout instantly. Free online TikTok live gift to cash calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate fluid font sizing instantly. Free online CSS clamp calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate required preamp gain instantly. Free online podcast mic gain calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate total GPU VRAM needed instantly. Free online LLM VRAM calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate total storage needed instantly. Free online CCTV storage calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate print weight and total filament cost instantly. Free online 3D printing cost calculator with live formulas, unit conversion and a step-by-step breakdown.

Compare the cost of a journey by petrol, diesel or electric vehicle, split it between passengers, and see the per-mile and per-kilometre running cost.

Scale any recipe up or down by servings and convert cup measures to grams by ingredient, with pan-size adjustment and baking-time guidance.

Enter a target dough weight and percentages to get exact flour, water, salt, yeast and levain weights, with dough-per-loaf and batch scaling.

Get exact coffee and water weights for French press, V60, Chemex, AeroPress, espresso and cold brew, with bloom volume, grind size and brew time.

Size a solar array and battery bank from your monthly consumption and peak sun hours, including system losses, days of autonomy and depth of discharge.

Calculate exactly how much liquid chlorine, cal-hypo or dichlor to add to reach your target free chlorine level, including shock dosing and CYA guidance.

Convert shoe sizes between US, UK, EU, Japanese and centimetre foot-length systems for men, women and children, with a fit and width guide.

Get a watering interval tailored to plant type, pot material and size, light exposure, humidity and season, with volume per watering and overwatering signs.

Project a car's resale value each year from purchase price, age, mileage and condition, with total depreciation cost per year and per mile.

Calculate daily water, sodium, potassium and magnesium needs during a fast based on body weight, fasting hours and climate, with a DIY electrolyte recipe.

Calculate exact resin and hardener quantities instantly. Free online epoxy resin calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate exact wax and fragrance oil weight instantly. Free online candle making calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate real generator watts and safe appliance load instantly. Free online kVA to watts calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate yearly electricity cost of a NAS or home server instantly. Free online power cost calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate your aquarium stocking capacity percentage instantly. Free online aquarium stocking calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate the exact nutrient dose to hit target PPM instantly. Free online hydroponic PPM and EC calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate your solar string's cold and hot voltage instantly. Free online solar string voltage calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate exactly how many bags of concrete you need instantly. Free online concrete bag calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate exactly how much fertilizer to spread instantly. Free online lawn fertilizer calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate exactly how much charcoal and wood you'll need instantly. Free online BBQ smoker fuel calculator with live formulas, unit conversion and a step-by-step breakdown.

Calculate exactly how much coop and run space your flock needs instantly. Free online chicken coop size calculator with live formulas, unit conversion and a step-by-step breakdown.

Estimate real-world electric scooter range from battery watt-hours, rider weight, riding mode and terrain. Get miles, km and Wh-per-mile efficiency instantly.