Calculators

Calculate your Body Mass Index from height and weight

Calculate daily calorie needs using Harris-Benedict formula

Calculate ideal weight using Devine, Robinson, and Miller formulas

Estimate body fat percentage using the US Navy method

Estimate your pregnancy due date and current gestational week

Find your most fertile days and estimate your next ovulation

Estimate the date of conception from a due date, last period, or birth date

Find your pregnancy week, trimester, and due date on any date

Find the best time to sleep or wake up based on 90-minute sleep cycles

Convert clinical laboratory values between conventional units (such as mg/dL) and SI units (such as mmol/L and µmol/L).

Calculate monthly payments, total interest, and amortization

Estimate your monthly home-loan payment and total interest

See a full payment-by-payment breakdown of principal and interest

Work out a car loan's monthly payment, total interest and total cost

Calculate compound interest growth with chart visualization

Calculate simple interest on a principal and see how it grows year by year

Calculate monthly savings needed to reach your goal

Calculate tip amount and split bill among friends

Project how much your retirement savings could grow

Calculate return on investment, gain and annualised CAGR

See how inflation changes the value of money over time

Convert pay between hourly, daily, weekly, monthly and annual

Add or remove sales tax / VAT from any price, or find the effective tax rate

Find selling price, profit, gross margin and markup from cost

Add up worked hours from clock-in/out times, subtract breaks, split overtime and total your pay

Plan how fast you can be debt-free with the snowball or avalanche method

Calculate your down payment, loan amount, cash to close and whether PMI applies

Add up your assets and liabilities to find your net worth and asset mix

Calculate exact age in years, months, days, and more

Calculate the number of days between two dates

Add or subtract days, weeks, months, and years, or count business days

Count working days excluding weekends and public holidays. Supports Japan and the US, with holidays computed automatically so they are always current.

Get the ISO week number for any date, and convert a week number back to dates.

Find what day of the week any date falls on, with the ISO week number, day of year, leap-year status, days from today, and zodiac sign.

Count how many days are left until an event, anniversary, birthday or holiday. Supports any date, yearly anniversaries and the next holiday.

Add and subtract time, find the duration between two times, and add or subtract a duration to a clock time.

Convert between Gregorian years and Japanese eras (Meiji, Taishō, Shōwa, Heisei, Reiwa) and find the zodiac sign (sexagenary cycle) for any year.

Calculate discounted price and savings amount

Split bill with tax and tip among multiple people

Estimate the fuel and money a trip needs from distance, fuel economy and price

Work out the energy and money an appliance uses per day, month and year from its wattage, run-time and your price per kWh

Solve for speed, distance, or time with any units

Calculate the area of rooms and spaces in ft², m², and more

Calculate theoretical speed, actual speed, slip and the required pitch from propeller pitch, engine RPM and gear (reduction) ratio.

Convert between volume and weight using a substance's density (water, concrete, sand, flour and more).

Estimate your basal metabolic rate with three formulas

Total daily energy expenditure from BMR and activity

Split your calories into protein, carbs, and fat

Estimate your body surface area with five formulas

Calculate 5 heart rate training zones by age

Calculate pace, speed, and race finish time predictions

Calculate recommended daily water intake

Estimate your one-rep max from any set with six proven formulas

Estimate your fat-free mass with three validated formulas

Find the recommended arrow spine (stiffness) from your draw weight, arrow length, point weight and bow type.

Calculate your grade point average on the 4.0 scale

Calculate your weighted grade or the score you need on the final

Find the score you need on your final exam to reach your target grade

Work out 'P% of X', 'A is what % of B', percent change, and increase/decrease by a percentage — all on one page.

Add, subtract, multiply and divide fractions with step-by-step work

Online scientific calculator with trigonometry, logarithms, powers and parentheses

Mean, median, mode, range, variance and standard deviation from a list of numbers, with a histogram

Solve any triangle from sides and angles (SSS, SAS, ASA, AAS, SSA, right) with a scaled diagram

Find the slope, line equation, distance and midpoint from two points, with a graph

Simplify ratios, solve proportions and compare ratios with step-by-step work

Find the greatest common factor and least common multiple with prime factorisation

Calculate nPr and nCr exactly with step-by-step working

Instantly compute bⁿ from a base and exponent. Supports negative and fractional exponents and 0⁰, with a repeated-multiplication visualization.

Instantly compute logₐ(x) from a value and base. Also shows natural log (ln), common log (log₁₀) and binary log (log₂), with a function graph.

Compute magnification, true field of view, exit pupil and resolution for any telescope + eyepiece, and visualize whether a target fits in the view

Estimate peak altitude, velocity and time to apogee (with air drag) from your airframe and motor, plus the parachute descent rate.

Estimate concrete volume and bags for slabs and columns

Estimate how much paint you need for a room or wall

Estimate how many tiles and boxes you need for a floor or wall

Work out how much mulch you need by volume, bags and weight

Estimate the flooring area to buy and how many boxes you need

Work out how much gravel you need by volume and weight

Estimate posts, rails and pickets for a fence run

Estimate roof area, squares and shingle bundles from the footprint and pitch

Scale conversion, grade and helix design in one place — with diagrams to plan your layout.

Work out the heater output your greenhouse needs and its heating cost. Enter dimensions or surface area, the cladding, and the indoor target and outdoor design-low temperatures to get the required output (W, kW, BTU/h) and the electricity cost from the heat loss.