All calculators.

Estimate monthly payments, total interest, and full amortization for a home loan.

Monthly payment, interest, and payoff schedule for any fixed-term loan.

Project growth of savings with regular contributions and compounding.

Interest without compounding — useful for short-term loans and bonds.

Compute annualized return (CAGR) and total gain for an investment.

Project your retirement nest egg and monthly income in retirement.

Split a bill, add a tip, and get each person's share.

Compute sales tax on a purchase or reverse-calculate pre-tax price.

Estimate US federal income tax for 2024 brackets (single or married filing jointly).

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

Convert between major currencies using indicative reference rates.

See how purchasing power changes over time at a given inflation rate.

Body Mass Index for adults, with WHO category interpretation.

Basal Metabolic Rate via Mifflin-St Jeor — calories your body burns at rest.

Total Daily Energy Expenditure — daily calories needed to maintain, lose, or gain weight.

US Navy method — body fat percentage from tape measurements.

Ideal body weight ranges via Devine, Robinson, and Miller formulas.

Daily protein, carb, and fat targets from a calorie goal.

Estimate due date from last menstrual period (Naegele's rule).

Estimate fertile window from cycle start date.

Daily water target based on body weight and activity.

Target heart rate zones for training (Karvonen method).

What is X% of Y, X is what % of Y, and percentage change — all in one place.

Percentage increase or decrease between two numbers.

Add, subtract, multiply, or divide two fractions and simplify the result.

Simplify a ratio or solve A:B = C:? for a missing term.

Solve A/B = C/D for the missing value.

Evaluate a math expression with +, −, ×, ÷, ^, sqrt, sin, cos, tan, log, ln, and π.

Solve ax² + bx + c = 0 for real or complex roots.

Mean, variance, and standard deviation (sample or population) of a dataset.

Central tendency measures for any list of numbers.

Greatest common divisor and least common multiple of two integers.

Exact age in years, months, and days between two dates.

Days, weeks, months, and years between two dates.

Find the date N days, weeks, months, or years from any date.

Duration between two times of day, in hours and minutes.

Days remaining until a target date.

Volume of concrete needed for a slab, plus 10% waste allowance.

Liters of paint required, allowing for coats and coverage.

How many tiles you need for an area, with waste allowance.

Convert roof pitch (rise/run) to angle in degrees and slope percent.

Compute board feet of lumber for pricing and take-offs.

Cost of fuel for a trip based on distance, efficiency, and price.

Convert between miles-per-gallon and liters-per-100km.

How long a trip will take at a steady speed.

Sale price after a percentage or fixed discount.

Grade point average from letter grades and credit hours (US 4.0 scale).

What score do I need on the final to hit a target grade?

Estimate password entropy and time to crack under a plausible attack.

Cryptographically-random integer in a range.