Probability Calculator
Single and combined event probability, odds and repeated trials.
Calculators
Everyday maths, money and measurements, worked out for you.
217 free tools
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Speed Calculator
Solve speed, distance or time and convert between speed units.
Scientific Notation Calculator
Convert to and from scientific, E and engineering notation.
Lean Body Mass Calculator
Lean mass and fat mass from measurements or body fat.
Time Duration Calculator
The time between two moments, in every unit.
Big Number Calculator
Exact arithmetic on numbers of any size, using BigInt.
401k Calculator
Projected balance with employer match and contribution limits.
Social Security Calculator
How your benefit changes with the age you claim.
Hours Calculator
Count the hours between a start and end time, breaks deducted.
Mortgage Calculator
Monthly mortgage payment with tax, insurance and total interest.
Pace Calculator
Solve pace, time or distance for running, cycling, swimming or walking.
Basic Calculator
A full keypad calculator with memory keys and a running tape.
BAC Calculator
Blood alcohol estimate by the Widmark formula, over time.
Salary Calculator
Convert pay between hourly, daily, weekly, monthly and annual.
Square Footage Calculator
Area of a room in square feet, metres or yards.
Bond Calculator
Bond price, current yield and yield to maturity.
SIP Calculator
Project a systematic investment plan with monthly contributions.
Credit Card Calculator
What minimum payments really cost, and how to beat them.
One Rep Max Calculator
Estimate your 1RM from a set, plus a full percentage table.
Ohms Law Calculator
Solve for volts, amps, ohms or watts from any two.
Amortization Calculator
Every payment split into principal and interest, with totals.
GFR Calculator
Estimated GFR by CKD-EPI 2021, MDRD and Cockcroft-Gault.
Percentage Change Calculator
Increase, decrease and the difference between two numbers.
Molarity Calculator
Molarity, moles, mass or volume, plus dilutions.
Weight Watcher Points Calculator
Points from nutrition labels, plus a daily allowance estimate.
Logarithm Calculator
Log to any base, natural log and antilog, with the change of base shown.
Percentage Calculator
Work out percentages, percentage change and reverse percentages.
Statistics Calculator
Full descriptive statistics with quartiles, spread and outliers.
Income Tax Calculator
Estimate tax across progressive bands with your own rates.
Dice Roller
Roll any dice notation, with modifiers and statistics.
Exponent Calculator
Raise any number to any power, including negative and fractional exponents.
Square Root Calculator
Square roots, cube roots and any nth root, exact or decimal.
Ratio Calculator
Simplify ratios, scale them up and share a total by any ratio.
Depreciation Calculator
Straight line, declining balance and sum-of-years schedules.
Currency Calculator
Convert between currencies using a rate you set, with fees included.
Tax Calculator
Add sales tax to a price or work out the pre-tax amount from a total.
Factor Calculator
Every factor of a number, in pairs, with prime factors marked.
Concrete Calculator
Concrete volume for slabs, footings, columns and steps.
Day Counter
Days between dates, with or without weekends and holidays.
Roth IRA Calculator
Tax-free growth, and whether Roth beats traditional for you.
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About these calculators
A full set of calculators for the numbers that come up in real life. Work out loan and mortgage repayments with a full amortisation schedule, add or strip VAT and GST, price a job by margin or markup, and find the break-even point for a product. Convert between any units, solve triangles and circles, and run descriptive statistics over a data set.
There are calculators for the everyday too: percentages and percentage change, tips and discounts, dates and durations, pace and fuel cost, and health estimates including BMI, BMR, TDEE and daily calories. Every one shows the formula it used rather than just an answer, and every one runs entirely in your browser, so nothing you enter is ever uploaded.