All Calculators
Every calculator on the site, grouped by category — 110 and counting.
Date & Time
6 calculators- Date & TimeLiveDays Between DatesCount the exact number of days between two dates, with an inclusive/exclusive toggle and a weeks-and-days breakdown.
- Date & TimeLiveDate Calculator (Add or Subtract Time)Add or subtract years, months, weeks, and days from any date. Handles month-end clamping (Jan 31 + 1 month → Feb 28) and shows the resulting day of the week.
- Date & TimeLiveBusiness Days CalculatorCount the business (working) days between two dates. Inclusive of both endpoints, excluding weekends and observed US federal holidays.
- Date & TimeLiveAge CalculatorCalculate exact age in years, months, and days from a birth date as of today or any chosen date. Shows total days, weeks, and months plus a countdown to the next birthday.
- Date & TimeLiveDays Until a Date CalculatorCount the days until a future date from today or any starting date. Shows a signed count, so past dates read as 'X days ago' and today reads as 0.
- Date & TimeLiveDeadline / Due Date CalculatorFind a due date by adding calendar days or business (working) days to a start date. Business mode skips weekends and observed US federal holidays.
Construction & DIY
4 calculators- Construction & DIYLiveConcrete Slab CalculatorCalculate concrete for a slab: cubic yards (or m³), the number of 80-lb bags including waste, and an optional cost. Set the length, width, thickness, and waste %.
- Construction & DIYLiveConcrete Bags CalculatorCalculate how many bags of pre-mixed concrete you need from a volume and waste allowance. Compares 40, 60 and 80 lb bags and rounds up to whole bags.
- Construction & DIYLiveGravel / Base CalculatorCalculate the gravel volume and tonnage for a driveway, base or fill. Includes a labeled compaction allowance and an editable material density, in tons or tonnes.
- Construction & DIYLivePaint CalculatorCalculate how many gallons of paint you need from the wall area, number of coats, and coverage rate. Deducts doors and windows and rounds up to whole gallons.
Conversions
18 calculators- ConversionsLiveCM to Inches ConverterConvert centimeters to inches and back. 1 inch equals 2.54 cm exactly, so the converter divides centimeters by 2.54 to give inches.
- ConversionsLiveKG to Lbs ConverterConvert kilograms to pounds and pounds to kilograms. One kilogram is about 2.2046 pounds, based on the exact 1 lb = 0.45359237 kg definition.
- ConversionsLiveFeet to Meters ConverterConvert feet to meters and meters to feet. One foot is exactly 0.3048 meters, so the converter multiplies feet by 0.3048 to give meters.
- ConversionsLiveMiles to Kilometers ConverterConvert miles to kilometers and kilometers to miles. One mile is exactly 1.609344 km, so the converter multiplies miles by 1.609344.
- ConversionsLiveMM to Inches ConverterConvert millimeters to inches and inches to millimeters. One inch is exactly 25.4 mm, so the converter divides millimeters by 25.4.
- ConversionsLiveOunces to Grams ConverterConvert ounces to grams and grams to ounces. One avoirdupois ounce is about 28.35 grams, so the converter multiplies ounces by 28.35.
- ConversionsLiveYards to Meters ConverterConvert yards to meters and meters to yards. One yard is exactly 0.9144 meters, so the converter multiplies yards by 0.9144.
- ConversionsLivePounds to Stone ConverterConvert pounds to stone and stone to pounds. One stone is exactly 14 pounds, so the converter divides pounds by 14.
- ConversionsLiveLiters to Gallons ConverterConvert liters to US gallons and gallons to liters. One US gallon is about 3.785 liters. UK gallon users should note the imperial gallon is larger.
- ConversionsLiveML to Cups ConverterConvert milliliters to US customary cups and back. One US customary cup is about 236.6 mL; the legal and metric cups differ slightly.
- ConversionsLiveMPH to KM/H ConverterConvert miles per hour to kilometers per hour and back. One mph is about 1.609 km/h, the same ratio that converts miles to kilometers.
- ConversionsLiveSquare Feet to Square Meters ConverterConvert square feet to square meters and back. One square foot is about 0.0929 m², the square of the 0.3048 m foot.
- ConversionsLiveAcres to Square Feet ConverterConvert acres to square feet and back. One acre is exactly 43,560 square feet, so the converter multiplies acres by 43,560.
- ConversionsLiveTime Converter (Hours to Minutes)Convert hours to minutes and minutes to hours. One hour is exactly 60 minutes, so the converter multiplies hours by 60.
- ConversionsLiveData Storage Converter (GB to MB)Convert gigabytes to megabytes and back using the decimal (SI) convention, where 1 GB = 1000 MB. The binary 1024 interpretation is explained too.
- ConversionsLiveFahrenheit to Celsius ConverterConvert between Fahrenheit, Celsius, and Kelvin. °C = (°F − 32) × 5/9 and °F = °C × 9/5 + 32, with Kelvin as °C + 273.15.
- ConversionsLiveRoman Numeral ConverterConvert numbers to Roman numerals and Roman numerals to numbers, from 1 (I) to 3999 (MMMCMXCIX), using standard subtractive notation.
- ConversionsLiveMM to Inch Fraction ConverterConvert millimeters to inches as a tape-measure fraction. 1 inch is exactly 25.4 mm; results round to the nearest 1/16 inch with the exact decimal shown too.
Everyday & Math
16 calculators- Everyday & MathLivePercentage CalculatorWork out what X% of a number is, what percentage one number is of another, or the percent change between two values. Three modes, one calculator.
- Everyday & MathLivePercentage Change CalculatorMeasure the percentage increase or decrease from an old value to a new one. Shows the signed percent change and the raw difference between the two figures.
- Everyday & MathLiveTip CalculatorWork out the tip, the grand total, and each person's share. Enter the bill, the tip percentage, and how many people are splitting it.
- Everyday & MathLiveDiscount CalculatorFind the sale price after a percentage off, and see exactly how much you save. Enter the original price and the discount percent.
- Everyday & MathLiveSales Tax CalculatorAdd sales tax to a subtotal and see the tax amount and grand total. Enter the pre-tax price and your local sales-tax rate.
- Everyday & MathLiveRatio CalculatorReduce a ratio like 12:8 to its simplest form and solve a proportion for a missing term. Enter two ratio terms and one known value.
- Everyday & MathLiveFraction CalculatorAdd, subtract, multiply, or divide two fractions and get the answer reduced to its simplest form. Enter each numerator and denominator.
- Everyday & MathLiveAverage CalculatorFind the average (arithmetic mean) of up to six numbers. Enter your values and see the mean, the count, and the total.
- Everyday & MathLiveStandard Deviation CalculatorFind the standard deviation of a data set — both the sample (n−1) and population (n) versions — plus the mean. Enter up to eight numbers.
- Everyday & MathLiveLCM and GCD CalculatorFind the greatest common divisor (GCD) and least common multiple (LCM) of two whole numbers using Euclid's algorithm. Enter two integers.
- Everyday & MathLiveCross-Multiply CalculatorSolve a/b = c/x for the missing value by cross-multiplying. Enter the three known numbers and get the fourth — the classic rule of three.
- Everyday & MathLiveGPA CalculatorCalculate your weighted GPA on a 4.0 scale from your course grades and credit hours. Enter each course's grade points and credits.
- Everyday & MathLiveGrade CalculatorCombine assignment, quiz, and exam scores by their weights into one overall course grade and letter. Enter each score and its weight.
- Everyday & MathLiveMarkup and Margin CalculatorTurn a cost and a selling price into markup percentage, margin percentage, and profit. See why markup and margin differ for the same sale.
- Everyday & MathLiveScientific Notation ConverterConvert a plain decimal number into normalised scientific notation (a × 10^n), with a coefficient between 1 and 10 and the power of ten.
- Everyday & MathLiveSquare Footage CalculatorFind the area of a rectangular room or space from its length and width, in square feet and square yards. Pure area arithmetic.
Fitness & Health
22 calculators- Fitness & HealthLiveBMI CalculatorCalculate your body mass index (BMI) from your height and weight and see the standard weight category. BMI is a screening estimate, not a diagnosis.
- Fitness & HealthLiveBMR CalculatorEstimate your basal metabolic rate (BMR) — the calories you burn at rest — with the Mifflin-St Jeor equation from your sex, weight, height, and age.
- Fitness & HealthLiveTDEE CalculatorEstimate your TDEE — the calories you burn in a day — from your BMR and activity level. TDEE is your maintenance calories: eat that much to hold your weight.
- Fitness & HealthLiveCalorie Deficit CalculatorSee the weekly weight loss from a daily calorie deficit. Note: the 3,500-kcal-per-pound rule is a simplified estimate that overstates long-term loss.
- Fitness & HealthLiveMacro CalculatorSplit a daily calorie target into grams of protein, carbohydrate, and fat from a percentage ratio, using the standard 4/4/9 Atwater calorie factors.
- Fitness & HealthLiveProtein Intake CalculatorEstimate your daily protein in grams from your body weight and goal. Needs are a range — from the RDA of 0.8 g/kg to about 2.0 g/kg for athletes.
- Fitness & HealthLiveWater Intake CalculatorEstimate daily water intake from your body weight using the 30–35 mL/kg rule of thumb. A general guide — adjust for activity, climate, and health.
- Fitness & HealthLiveIdeal Weight CalculatorEstimate a reference body-weight range for your height using the Devine, Robinson, Miller, and Hamwi formulas. A guide, not a target — bodies vary.
- Fitness & HealthLiveOne Rep Max CalculatorEstimate your one-rep max from a weight lifted for several reps, using the Epley and Brzycki formulas. A training estimate — never test a true 1RM unspotted.
- Fitness & HealthLiveTarget Heart Rate CalculatorFind your target training heart rate with the Karvonen heart-rate-reserve method, plus max-HR estimates (220−age and the more accurate Tanaka formula).
- Fitness & HealthLiveRunning Pace CalculatorWork out your running pace from a time and distance. Enter the minutes you ran and the miles you covered to get your seconds-per-mile pace.
- Fitness & HealthLiveBody Fat Calculator (Navy Method)Estimate your body fat percentage with the U.S. Navy (Hodgdon-Beckett) tape-measure method from your waist, neck, height, and (for women) hip. An estimate, not a diagnosis.
- Fitness & HealthLiveLean Body Mass CalculatorEstimate your lean (fat-free) body mass from weight and height using the Boer, James, and Hume formulas. A body-composition estimate, not a clinical measurement.
- Fitness & HealthLiveWaist-to-Hip Ratio CalculatorCalculate your waist-to-hip ratio (WHR) and see where it falls against the World Health Organization risk bands. A screening estimate, not a diagnosis.
- Fitness & HealthLiveVO₂max CalculatorEstimate your VO₂max (aerobic fitness) from your maximum and resting heart rate using the Uth-Sørensen formula. A rough estimate validated on trained adults.
- Fitness & HealthLiveBody Surface Area CalculatorCalculate your body surface area (BSA) from height and weight using the Mosteller and Du Bois formulas. A reference figure used in clinical dosing — not medical advice.
- Fitness & HealthLiveCalories Burned CalculatorEstimate the calories burned in a workout from your activity, body weight, and duration using MET values from the Compendium of Physical Activities.
- Fitness & HealthLiveMax Heart Rate CalculatorEstimate your maximum heart rate from your age using the familiar 220 − age rule and the more accurate Tanaka formula. An estimate, not a measured maximum.
- Fitness & HealthLiveSteps to Miles CalculatorConvert your daily step count to miles and kilometres using your stride length. See how far 10,000 steps really is for your height.
- Fitness & HealthLiveKatch-McArdle BMR CalculatorEstimate your basal metabolic rate from your lean body mass using the Katch-McArdle equation — more accurate than weight-based formulas for lean, athletic builds.
- Fitness & HealthLiveSleep Cycle CalculatorFind the best bedtime to wake up refreshed by counting back whole 90-minute sleep cycles from your alarm, plus time to fall asleep.
- Fitness & HealthLiveSmoking Cost CalculatorAdd up how much smoking costs over a day, year, or any period from your daily cigarettes, pack size, and pack price.
Finance & Loans
22 calculators- Finance & LoansLiveMortgage Payment CalculatorEstimate your monthly mortgage payment (principal and interest) from the loan amount, interest rate, and term. See the total interest paid over the life of the loan.
- Finance & LoansLiveLoan Payment CalculatorEstimate the monthly payment on a personal or installment loan from the amount, interest rate, and term, and see the total interest you will pay.
- Finance & LoansLiveAuto Loan CalculatorEstimate your monthly car payment after a down payment and trade-in. Enter the vehicle price, down payment, trade-in value, rate, and term to see the payment and total interest.
- Finance & LoansLiveAmortization Schedule CalculatorSee your loan's full amortization schedule month by month: how each payment splits between interest and principal, the running balance, and the payoff date.
- Finance & LoansLiveMortgage Affordability CalculatorEstimate how much house you can afford using the lender-standard 28/36 debt-to-income rule, with the conservative 25%-of-take-home-pay rule shown for comparison.
- Finance & LoansLiveDown Payment CalculatorWork out your down payment from a home price and percentage, see the loan amount, and find the 20% needed to avoid private mortgage insurance (PMI).
- Finance & LoansLiveCompound Interest CalculatorSee how a lump sum grows with compound interest. Enter the starting amount, annual rate, compounding frequency, and years to find the future value and interest earned.
- Finance & LoansLiveSimple Interest CalculatorCalculate simple interest (I = P × r × t) on a loan or deposit. Enter the principal, annual rate, and time to see the interest and the total amount.
- Finance & LoansLiveSavings Goal CalculatorFind the monthly amount to save to reach a goal. Enter your target, starting balance, expected return, and timeframe to see the required monthly contribution.
- Finance & LoansLiveInvestment Growth CalculatorProject the future value of an investment with regular monthly contributions. Enter a starting amount, monthly deposit, expected return, and years to see the total and growth.
- Finance & LoansLiveAPR to APY CalculatorConvert a nominal APR to its effective annual yield (APY) for a given compounding frequency, and confirm the inverse APY-to-APR conversion.
- Finance & LoansLiveSIP CalculatorEstimate the maturity value and returns of a systematic investment plan (SIP) from your monthly investment, expected return, and time horizon. Contributions are compounded monthly.
- Finance & LoansLiveRetirement CalculatorEstimate your retirement nest egg from your current balance, monthly contributions, and expected return, then see how long it lasts at your planned annual withdrawal.
- Finance & LoansLive401(k) CalculatorProject your 401(k) balance at retirement, including your employer's match. Enter your salary, contribution rate, match terms, and expected return.
- Finance & LoansLiveROI CalculatorCalculate your return on investment (ROI) as a percentage, plus the annualized return (CAGR), from what you invested, what it is worth, and how long you held it.
- Finance & LoansLiveCredit Card Payoff CalculatorSee how many months it takes to pay off a credit card at a fixed monthly payment, and how much total interest you will pay, from your balance and APR.
- Finance & LoansLiveDebt Payoff CalculatorCompare the debt snowball and debt avalanche methods across all your debts. See how long each takes to pay off and how much total interest you pay.
- Finance & LoansLiveRefinance Break-Even CalculatorFind the break-even month for a mortgage refinance: how long it takes the monthly savings to recoup your closing costs, from your balance, rates, and terms.
- Finance & LoansLiveRent vs Buy CalculatorCompare the total cost of renting against buying a home over a set number of years, after recovered equity, to see which is cheaper for your situation.
- Finance & LoansLiveInflation CalculatorSee what an amount of money will be worth after inflation, and what a future amount is worth in today's purchasing power, from the amount, rate, and number of years.
- Finance & LoansLiveCar Affordability CalculatorFind the most expensive car you can afford from your target monthly payment, loan rate, term, and down payment — the inverse of a car loan payment calculator.
- Finance & LoansLiveSalary Calculator (Hourly to Annual)Convert an hourly wage to an annual, monthly, and weekly salary from your hours per week and weeks per year. See what an hourly rate adds up to over a year.
Cooking & Baking
9 calculators- Cooking & BakingLiveCups to Grams ConverterConvert cups to grams (and grams to cups) for flour, sugar, butter, and 40+ ingredients using cited densities. Pick the US, UK, or metric cup standard.
- Cooking & BakingLiveRecipe ScalerScale any recipe to a new number of servings. Enter your ingredients and the original and desired yield, and every quantity resizes by the same factor.
- Cooking & BakingLiveDouble or Halve a RecipeDouble, halve, triple, or 1.5× any recipe in one step. Enter your ingredients and a multiplier, and every amount adjusts instantly.
- Cooking & BakingLiveButter ConverterConvert butter between sticks, cups, tablespoons, grams, and ounces. One US stick of butter is 113 grams, half a cup, or 8 tablespoons.
- Cooking & BakingLiveYeast ConverterConvert between active dry yeast and instant (rapid-rise) yeast. Instant yeast is about 25% more potent, so use 75% as much when swapping in.
- Cooking & BakingLiveOven Temperature ConverterConvert oven temperatures between Fahrenheit, Celsius, the oven-dial setting, and gas mark. 350°F is 180°C and gas mark 4.
- Cooking & BakingLiveBaking Pan Size ConverterFind out whether you can swap one baking pan for another. Compare pan areas to see if the batter fits — a 9-inch round is close to an 8-inch square.
- Cooking & BakingLiveCooking Time by WeightEstimate roasting time from weight. Enter the weight and minutes-per-pound rate for a turkey or roast — then confirm doneness with a thermometer.
- Cooking & BakingLiveBaker's Percentage CalculatorCalculate baker's percentages and dough hydration from ingredient weights. Flour is 100%; 500 g flour with 350 g water is 70% hydration.
Pregnancy & Due Date
8 calculators- Pregnancy & Due DateLiveDue Date CalculatorEstimate your due date from your last period, conception date, IVF transfer, or an ultrasound. One calculator, four dating methods — and a note on why due dates are estimates.
- Pregnancy & Due DateLiveGestational Age CalculatorFind your gestational age in weeks and days from your last period. Shows the exact weeks-and-days figure and trimester used in prenatal care.
- Pregnancy & Due DateLivePregnancy Week-by-Week CalculatorSee which week of pregnancy you are in and which trimester, week by week. Enter your last period date to find your current pregnancy week.
- Pregnancy & Due DateLiveConception Date CalculatorEstimate when you conceived from your last period and cycle length. Works backward using the fixed two-week luteal phase to date conception.
- Pregnancy & Due DateLiveOvulation & Fertile Window CalculatorEstimate your ovulation day and fertile window to plan for conception. Enter your last period and cycle length to find your most fertile days.
- Pregnancy & Due DateLivePregnancy Weight Gain CalculatorFind the recommended total pregnancy weight gain for your pre-pregnancy BMI, based on the IOM 2009 guidelines for a singleton pregnancy.
- Pregnancy & Due DateLivePeriod PredictorPredict your next period from your last period and cycle length. Shows your next period date plus the following few cycles.
- Pregnancy & Due DateLiveDue Date CountdownCount down the days until your due date. Enter your estimated due date to see how many days are left until your baby is due.
Automotive
5 calculators- AutomotiveLiveFuel Cost CalculatorWork out how much gas a trip will cost. Enter the distance, your car's MPG, and the price per gallon to see the fuel needed and the total cost.
- AutomotiveLiveGas Mileage CalculatorCalculate your car's gas mileage from miles driven and gallons used. See US MPG plus the L/100km and UK MPG equivalents.
- AutomotiveLiveMileage Reimbursement CalculatorCalculate mileage reimbursement or a deduction using the IRS standard mileage rates. Enter miles and choose business, medical/moving, or charitable.
- AutomotiveLiveFuel Savings CalculatorSee how much you would save on fuel each year by switching to a more efficient car. Enter annual miles, gas price, and each car's MPG.
- AutomotiveLiveRoad Trip Cost CalculatorEstimate the gas cost of a road trip and split it between travelers. Enter the distance, your car's MPG, the fuel price, and the number of people.