Answers in seconds with119 free calculators

Calculators for the arithmetic that comes up at school, at work and around the house — percentages, fractions, averages and ratios. Each one shows the working, so you can check the answer and learn the method.

• Percentage CalculatorFind X% of Y, X as a percent of Y, or the original whole.
• Percentage Change CalculatorPercentage increase or decrease from an old value to a new one.
• Scientific CalculatorType an expression; get trig, logs, powers and factorials with steps.
• Graphing CalculatorPlot up to 3 functions with intercepts, zeros, min/max and a table.
• Quadratic Formula CalculatorSolve ax² + bx + c = 0 with real or complex roots and steps.
• Fraction CalculatorAdd, subtract, multiply and divide fractions in lowest terms.
• Pythagorean Theorem CalculatorFind the hypotenuse or a missing leg, or check for a right angle.
• Slope CalculatorSlope, line equation, angle and distance from two points.
• Square Root CalculatorDecimal square root plus the exact simplified radical.
• Average CalculatorMean, median, mode and range of a list of numbers.
• Exponent CalculatorPowers with negative, decimal and fractional exponents, with steps.
• GCF CalculatorGreatest common factor of 2+ numbers, with prime factors and steps.
• LCM CalculatorLeast common multiple of 2+ numbers, with prime factors and steps.
• Long Division CalculatorQuotient, remainder and exact decimal, with every long-division step.
• Ratio CalculatorSolve proportions and simplify ratios to lowest terms.
• Decimal CalculatorAdd, subtract, multiply and divide decimals exactly, with steps.
• Proportion CalculatorSolve A/B = C/D for any missing term, or check a proportion.
• Ten Key CalculatorOnline adding machine with a tape, item count and decimal setting.

Calculators for borrowing, saving and investing — loan and mortgage payments, simple and compound interest, and return on investment. Each one shows how the numbers are worked out, so you can check the result and compare options.

• Mortgage CalculatorMonthly mortgage payment with taxes, insurance and HOA.
• Compound Interest CalculatorProject savings growth with compounding and monthly deposits.
• Loan CalculatorMonthly payment, total interest and amortization for a fixed-rate loan.
• Retirement CalculatorProject retirement savings, the nest egg you need and any gap.
• Salary to Hourly CalculatorAnnual salary to hourly wage and back, with pay per period.
• Retirement Withdrawal CalculatorHow long savings last, or how much you can withdraw each month.
• Amortization CalculatorMonth-by-month and yearly loan schedule, with extra payments.
• Auto Loan CalculatorMonthly car payment with sales tax, trade-in and down payment.
• Overtime Pay CalculatorWeekly gross pay with time-and-a-half and double-time hours.
• Profit Margin CalculatorMargin and markup from cost and price, or price from a target margin.
• Refinance CalculatorNew payment, monthly savings, break-even month and lifetime savings of a refi.
• Credit Card Payoff CalculatorMonths to pay off a card, or the payment for a target date.
• CAGR CalculatorCompound annual growth rate, total growth, or end value from a rate.
• ROI CalculatorTotal and annualized return on an investment.
• 403(b) CalculatorProject a 403(b) balance with employer match, raises and catch-up limits.
• Simple Interest CalculatorFind interest with I = P × r × t over years, months or days.
• TSP CalculatorProject Thrift Savings Plan growth with agency match and catch-up.
• Maryland Paycheck CalculatorEstimate 2026 Maryland take-home pay after federal, state and county tax.

Calculators for counting days, finding exact ages, moving a date forward or back, and totaling hours worked. Each one shows how the answer was reached, including how leap years and month ends were handled.

• Age CalculatorExact age in years, months and days on any date.
• Days Between Dates CalculatorCount days, weeks and weekdays between two dates.
• Hours CalculatorHours worked between two times, in decimal hours too.
• Date CalculatorAdd or subtract days, weeks, months or years from a date.
• Time Card CalculatorWeekly hours from clock-in and clock-out times, with pay.
• Business Days CalculatorCount or add working days, excluding US federal holidays.
• Military Time Converter12-hour AM/PM time to 24-hour military time and back.
• Day of the Week CalculatorThe weekday for any date, with Zeller's formula worked out.

Calculators for the money and planning questions of daily life — tips, discounts, sales tax, splitting bills, fuel costs and comparing prices — with the working shown so you can check every answer.

• Tip CalculatorTip, total and per-person share, with a round-up option.
• Discount CalculatorSale price, savings and percent off, including stacked discounts.
• Sales Tax CalculatorAdd sales tax, remove it from a total, or find the rate.
• Gas Cost CalculatorFuel cost of any drive from distance, mpg and gas price.
• Split Bill CalculatorSplit a check with tax and tip, evenly or by share.
• MPG CalculatorReal-world mpg from a fill-up, plus L/100 km and km/L.
• Trip Cost CalculatorRoad trip budget with fuel, lodging, food and cost per person.
• Unit Price CalculatorCompare package sizes by price per unit and find the better buy.
• Mythic Plus Score CalculatorWoW Mythic+ dungeon score, overall rating and keys for a target.
• Grow a Garden Pet CalculatorPet weight by Age, Age for a target kg, and XP to level up.
• Life Path Number CalculatorYour numerology life path number from a birth date, with steps.
• Tarkov Currency CalculatorConvert Tarkov roubles, dollars and euros at editable trader rates.

Calculators for body measurements, calories, nutrition and heart-rate training, built on published formulas such as Mifflin-St Jeor and the CDC BMI categories. Results are estimates, not medical advice.

• BMI CalculatorBody mass index from height and weight, with CDC adult categories.
• Calorie CalculatorDaily calories to maintain, lose or gain weight at a chosen rate.
• BMR CalculatorBasal metabolic rate with Mifflin-St Jeor, Harris-Benedict or Katch-McArdle.
• Body Fat CalculatorBody fat % from tape measurements (US Navy method), with fat and lean mass.
• Macro CalculatorProtein, carb and fat grams from your daily calories and a macro split.
• TDEE CalculatorTotal daily energy expenditure from BMR and activity level.
• Heart Rate Zones CalculatorFive training zones in bpm from age, with optional resting heart rate.
• Ideal Weight CalculatorIdeal body weight by four formulas plus the healthy BMI range.
• Dental Implant Cost CalculatorTotal an implant quote, subtract insurance and see a monthly payment.

Unit converters for length, weight, volume, temperature, speed and more. Each converter uses exact unit definitions and shows the value in every related unit at once.

• Celsius to Fahrenheit Converter°C to °F with steps and the double-plus-30 shortcut.
• Cm to Inches ConverterCentimeters to inches, feet and inches, and tape-measure fractions.
• Kg to Lbs ConverterKilograms to pounds, pounds and ounces, and stone.
• Length ConverterConvert mm, cm, m, km, inches, feet, yards, miles and nautical miles.
• Temperature ConverterConvert °F, °C and K with the formula shown step by step.
• Weight ConverterConvert mg, g, kg, metric tons, ounces, pounds, stone and US tons.
• Volume ConverterConvert mL, liters, cups, fl oz, gallons and cubic units in one place.
• Speed ConverterConvert mph, km/h, m/s, ft/s and knots.

Calculators for describing data and working with probability — standard deviation, z-scores, percentiles, combinations and random numbers — with each formula and step explained.

• Standard Deviation CalculatorSample and population standard deviation, variance and mean of a list.
• Random Number GeneratorRandom whole numbers or decimals in any range, with or without repeats.
• Probability CalculatorAnd, or, not and at-least-once probabilities for independent events.
• Z-Score CalculatorZ-score from a value, mean and standard deviation, with percentile.
• Combination CalculatorExact nCr and nPr, with or without repetition, for n up to 1,000.
• Percentile CalculatorValue at the Pth percentile, or the percentile rank of a value.

Calculators for students and teachers — GPA, final exam grades, weighted grades and test scores — so you can see exactly where a grade comes from and what you need next.

• GPA CalculatorSemester GPA on the 4.0 scale from letter grades and credits.
• Grade CalculatorClass grade and letter from category weights or total points.
• Final Grade CalculatorScore you need on the final exam to reach a target class grade.
• Cumulative GPA CalculatorCombine your current GPA and credits with a new semester.
• Test Grade CalculatorTest percentage and letter from questions missed, with a chart.
• Weighted Grade CalculatorWeighted average of grades, with weights on any scale.
• AP Psychology Score CalculatorEstimate a 1–5 AP Psychology score from MCQ, AAQ and EBQ points.
• AP Statistics Score CalculatorEstimate a 1–5 AP Statistics score for the 2027 or older exam format.
• UPSC Age Limit CalculatorUPSC CSE age on 1 August, category relaxation and attempts left.
• NDA Age Limit CalculatorCheck NDA (I) and NDA (II) age eligibility from your date of birth.

Material estimators for home projects — concrete, gravel, paint, tile, flooring and square footage — that turn measurements into quantities to buy, with waste allowances explained. Estimates only, not engineering advice.

• Concrete CalculatorCubic yards and 40/60/80 lb bag counts for slabs, columns and steps.
• Square Footage CalculatorArea in sq ft, sq yd and m² for rooms, triangles, circles and L-shapes.
• Paint CalculatorGallons (and quarts) of wall paint after doors, windows and coats.
• Flooring CalculatorBoxes of laminate, vinyl or wood flooring from room areas and waste.
• Tile CalculatorTiles and boxes from area, tile size, grout joint and waste.
• Gravel CalculatorCubic yards and tons of gravel from length, width and depth.

Calculators for mechanics and electricity — velocity, acceleration, force, kinetic energy, density and Ohm's law — with SI units, unit options and every equation shown.

• Ohm's Law CalculatorEnter any two of V, I, R and P to get the other two.
• Acceleration CalculatorAcceleration from Δv ÷ t, from distance and time, or from F ÷ m.
• Density CalculatorFind density, mass or volume with ρ = m ÷ V.
• Force CalculatorSolve F = ma for force, mass or acceleration.
• Kinetic Energy CalculatorFind kinetic energy, mass or velocity with KE = ½mv².
• Velocity CalculatorAverage velocity v = d ÷ t, final velocity v = v₀ + at, distance and time.
• Boiler Feed Pump CalculatorFeedwater flow, total dynamic head, shaft and motor power for a boiler.

Calculators for solutions, gases and radioactive decay — molarity, dilution, the ideal gas law and half-life — with the equation and units shown for lab work and homework.

• Molarity CalculatorFind molarity, grams of solute or solution volume.
• Dilution CalculatorSolve C₁V₁ = C₂V₂ and find how much diluent to add.
• Ideal Gas Law CalculatorSolve PV = nRT for pressure, volume, moles or temperature.
• Half-Life CalculatorFind amount left, time elapsed or half-life of decay.

Calculators for training and performance — running pace, race time predictions, one-rep max and calories burned — based on established formulas from exercise science.

• Calories Burned CalculatorEstimate calories burned for 40+ activities from weight and duration.
• Pace CalculatorFind pace, finish time or distance for any run, per mile or per km.
• One Rep Max CalculatorEstimate your 1RM from weight and reps, with a %1RM training table.
• Race Time PredictorPredict 5K to marathon times from one recent race with Riegel's formula.

Kitchen calculators for scaling recipes, converting cups to grams by ingredient, coffee ratios and turkey cooking times, so recipes come out right at any size.

• Recipe ScalerScale a recipe up or down and get practical cup and spoon amounts.

Calculators for genetics, population growth and pet ages — Punnett squares, exponential growth and dog and cat age in human years — with the biology behind each result explained.

• Dog Age CalculatorDog years to human years by size chart and DNA-based formula.
• Cat Age CalculatorCat years to human years, with the AAHA/AAFP life stage.
• Punnett Square CalculatorMonohybrid, dihybrid and trihybrid crosses with ratios.
• Population Growth CalculatorExponential and logistic population growth, rate and doubling time.

Calculators for home energy and emissions — electricity cost, kWh use, solar panel sizing and car CO2 — using your own rates and published EPA factors, with no hidden assumptions.

• Electricity Cost CalculatorRunning cost of any appliance per day, month and year.
• kWh CalculatorKilowatt-hours from watts, or from amps and volts.
• Solar Panel CalculatorSolar system size and panel count from your kWh use.
• Car CO2 Emissions CalculatorTailpipe CO2 for a trip or a year from miles and mpg.