Precise answers, with the maths you can check.
Fast, free, and genuinely useful online calculators. No sign-up, no clutter. Every result shows the formula behind it.
Finance
Loan, mortgage, interest, VAT, ROI
Browse →Health
BMI, calories, body fat, due date
Browse →Math
Percentage, fraction, quadratic, slope
Browse →Science
Ohm's law, density, molarity, force
Browse →Everyday
Fuel cost, age, hours, tip
Browse →Shopping
Discount, tip, unit price, markup
Browse →Popular calculators
Mortgage Calculator
Estimate your full monthly mortgage payment, including tax and insurance.
OpenLoan Repayment Calculator
Enter the loan amount, interest rate and term to see your monthly repayment, the total you will pay back, and the total interest.
OpenPercentage Calculator
Three common percentage questions in one place, pick a mode and type your numbers.
OpenCurrency Converter
Convert between 160+ currencies using live exchange rates. Pick your currencies and enter an amount.
OpenCompound Interest Calculator
See how much a deposit grows over time when interest is added back and earns interest of its own.
OpenBMI Calculator
Enter your height and weight, in metric or imperial units, to see your Body Mass Index and category.
OpenScientific Calculator
A full scientific calculator with trig, logs, powers, roots and more. Type or tap.
OpenGPA Calculator
Enter your course grades and credits to get your grade point average on a 4.0 scale.
OpenSalary Calculator
Convert a yearly salary into hourly, daily, weekly and monthly pay.
OpenNumbers are for everyone
From students and tradespeople to engineers, bankers and lab techs, Calculator Den is the quick, trustworthy tool people reach for when the answer has to be right.
Recently added
Debt-to-Income Ratio Calculator
Work out your debt-to-income ratio, the number lenders check first when you apply for a mortgage or loan.
OpenLoan-to-Value (LTV) Calculator
Find your loan-to-value ratio, the figure that decides your mortgage rate and whether you pay mortgage insurance.
OpenCAGR Calculator
Work out the compound annual growth rate, the smoothed yearly rate that turned your start value into your end value.
OpenFuture Value Calculator
See what a sum of money today will grow to in the future at a given interest rate.
OpenPresent Value Calculator
Find what a future sum of money is worth in today's terms at a given discount rate.
OpenSleep Calculator
Work out the best time to sleep or wake up so you finish on a full sleep cycle and wake up less groggy.
OpenDebt Consolidation Calculator
Compare keeping your current debts against one consolidation loan, for both the monthly payment and the total interest.
OpenPercentage Increase Calculator
Find the percentage increase or decrease from one number to another.
OpenFind by what you need
I'm buying a car
I'm starting a business
I'm managing money
Finance
Loan Repayment Calculator
Enter the loan amount, interest rate and term to see your monthly repayment, the total you will pay back, and the total interest.
OpenCompound Interest Calculator
See how much a deposit grows over time when interest is added back and earns interest of its own.
OpenVAT / Sales Tax Calculator
Add tax to a price, or strip tax out of a tax-inclusive price, at any rate.
OpenMortgage Calculator
Estimate your full monthly mortgage payment, including tax and insurance.
OpenSimple Interest Calculator
Work out simple interest and the total owed or earned over a set time.
OpenSavings Goal Calculator
Find the monthly deposit needed to hit a savings goal by your target date.
OpenSalary Calculator
Convert a yearly salary into hourly, daily, weekly and monthly pay.
OpenRetirement Calculator
Estimate the nest egg you will have at retirement, and the income it could provide.
OpenCar Loan Calculator
Work out your monthly car payment and the total interest you will pay.
OpenInvestment Calculator
See how an investment grows with an initial amount and monthly contributions.
OpenCredit Card Payoff Calculator
See how long it will take to clear a credit card and the interest it costs.
OpenInflation Calculator
See how inflation changes what money is worth over time.
OpenROI Calculator
Work out your return on investment, profit and annualised return.
OpenAPY Calculator
Turn a nominal rate and compounding frequency into the real annual yield (APY).
OpenDown Payment Calculator
See your down payment amount and the loan you would need from a price and percentage.
OpenRule of 72 Calculator
Estimate how long money takes to double, or the rate needed to double it.
OpenBreak-Even Calculator
Find how many units you must sell to cover your costs.
OpenNet Worth Calculator
Work out your net worth: what you own minus what you owe.
OpenDebt-to-Income Ratio Calculator
Work out your debt-to-income ratio, the number lenders check first when you apply for a mortgage or loan.
OpenLoan-to-Value (LTV) Calculator
Find your loan-to-value ratio, the figure that decides your mortgage rate and whether you pay mortgage insurance.
OpenCAGR Calculator
Work out the compound annual growth rate, the smoothed yearly rate that turned your start value into your end value.
OpenFuture Value Calculator
See what a sum of money today will grow to in the future at a given interest rate.
OpenPresent Value Calculator
Find what a future sum of money is worth in today's terms at a given discount rate.
OpenLoan Early Payoff Calculator
See how much sooner you clear a loan, and how much interest you save, by paying extra.
OpenDebt Consolidation Calculator
Compare keeping your current debts against one consolidation loan, for both the monthly payment and the total interest.
OpenCar Affordability Calculator
Work out the most expensive car you can afford from a comfortable monthly payment.
OpenCar Lease Calculator
Estimate your monthly car lease payment from the price, residual and money factor.
OpenCurrency Converter
Convert between 160+ currencies using live exchange rates. Pick your currencies and enter an amount.
OpenMath
Percentage Calculator
Three common percentage questions in one place, pick a mode and type your numbers.
OpenGPA Calculator
Enter your course grades and credits to get your grade point average on a 4.0 scale.
OpenFinal Grade Calculator
Find the score you need on your final exam to reach the grade you want.
OpenFraction Calculator
Add, subtract, multiply or divide two fractions, simplified automatically.
OpenSquare Footage Calculator
Calculate the area of a room or space, plus perimeter and material cost.
OpenAverage (Mean) Calculator
Enter a list of numbers to get the mean, median, sum and count.
OpenStandard Deviation Calculator
Get the standard deviation, variance and mean of a data set.
OpenRatio Calculator
Simplify a ratio and solve a proportion in one place.
OpenTest Grade Calculator
Turn questions answered correctly into a percentage and letter grade.
OpenGCF & LCM Calculator
Find the greatest common factor and least common multiple of two numbers.
OpenQuadratic Formula Calculator
Solve ax² + bx + c = 0 for its roots, real or complex.
OpenSlope Calculator
Find the slope and equation of the line through two points.
OpenTemperature Converter
Convert a temperature between Celsius, Fahrenheit and Kelvin.
OpenPythagorean Theorem Calculator
Find the hypotenuse of a right triangle from the two shorter sides.
OpenScientific Notation Calculator
Convert any number to scientific notation, showing the coefficient and the power of ten.
OpenRoman Numeral Converter
Turn any whole number from 1 to 3999 into Roman numerals.
OpenPercentage Increase Calculator
Find the percentage increase or decrease from one number to another.
OpenScientific Calculator
A full scientific calculator with trig, logs, powers, roots and more. Type or tap.
OpenScience
Ohm's Law Calculator
Enter any two of voltage, current and resistance and get the third, plus power.
OpenDensity Calculator
Find density from mass and volume with the formula density = mass divided by volume.
OpenForce Calculator
Calculate force from mass and acceleration using Newton's second law, F = ma.
OpenKinetic Energy Calculator
Find the kinetic energy of a moving object from its mass and velocity.
OpenMolarity Calculator
Find the molarity (concentration) of a solution from moles of solute and volume.
OpenMolar Mass Calculator
Type a chemical formula, like H2SO4 or Ca(OH)2, to get its molar mass in grams per mole.
OpenIdeal Gas Law Calculator
Find the moles of a gas from its pressure, volume and temperature using PV = nRT.
OpenShopping
Discount Calculator
Enter the original price and the discount to see the final price and how much you save.
OpenUnit Price Calculator
Compare two products by their price per unit to see which is truly the better deal.
OpenMarkup Calculator
Set your selling price by adding a markup percentage to what an item costs you.
OpenProfit Margin Calculator
Enter your cost and selling price to see profit, profit margin and markup.
OpenDouble Discount Calculator
See the real final price when two discounts or coupons stack on top of each other.
OpenEveryday
Wedding Budget Calculator
Enter your total budget to see a typical breakdown across every wedding category.
OpenCar Cost of Ownership Calculator
Estimate the true cost of owning a car, including depreciation and running costs.
OpenTip Calculator
Enter the bill, choose a tip percentage, and split it between your group.
OpenAge Calculator
Enter a date of birth to see the exact age in years, months and days, updated to today.
OpenDate Difference Calculator
Pick two dates to count the days and weeks between them.
OpenFuel Cost Calculator
Estimate how much fuel a trip will use and what it will cost, in any units.
OpenHours Calculator
Work out the hours between a start and end time, minus any break.
OpenHealth
BMI Calculator
Enter your height and weight, in metric or imperial units, to see your Body Mass Index and category.
OpenDaily Calorie Calculator
Estimate the calories your body burns at rest and across your day.
OpenPregnancy Due Date Calculator
Estimate your due date and how many weeks along you are, based on your last period.
OpenA1C to Average Blood Sugar Calculator
Convert an A1C percentage to an estimated average blood glucose level.
OpenBlood Sugar Converter (mg/dL ↔ mmol/L)
Convert a blood glucose reading between mg/dL and mmol/L.
OpenSleep Calculator
Work out the best time to sleep or wake up so you finish on a full sleep cycle and wake up less groggy.
OpenBody Fat Calculator
Estimate your body fat percentage using the US Navy tape method and a few measurements.
OpenIdeal Weight Calculator
Estimate a healthy target weight for your height using three well-known formulas.
OpenMacro Calculator
Split your daily calories into protein, carbs and fat for the diet style you choose.
OpenCalories Burned Calculator
Estimate how many calories an activity burns from your weight and how long you did it.
OpenBody Surface Area (BSA) Calculator
Work out your body surface area in square metres using the Mosteller formula.
OpenLean Body Mass Calculator
Estimate how much of your body weight is lean mass versus fat, using the Boer formula.
OpenWater Intake Calculator
Estimate how much water to drink each day from your weight and exercise.
OpenOvulation Calculator
Estimate your ovulation day and fertile window from your last period and cycle length.
OpenPeriod Calculator
Predict your upcoming period dates from your last period and average cycle length.
OpenPregnancy Weight Gain Calculator
See the healthy total weight gain range for your pregnancy based on your starting BMI.
OpenConception Calculator
Estimate when conception likely happened, based on your due date.
OpenOne Rep Max (1RM) Calculator
Estimate the most you could lift for a single rep from a set you have already done.
OpenRunning Pace Calculator
Turn a distance and a time into your pace per km and per mile, plus your speed.
OpenTarget Heart Rate Calculator
Find your max heart rate and the training zones for moderate and vigorous exercise.
Open