Calculators

Calculate rectangular area and estimate material quantity with waste allowance.

Add, subtract, multiply, and divide fractions with step-by-step solutions.

Simplify ratios to lowest terms, solve equivalent proportions, and scale quantities.

Calculate proportional dimensions, simplify aspect ratios, and inspect screen resolutions with live visual preview.

Calculate exact binomial probabilities for a chosen number of coin flips.

Calculate Financial Independence Retire Early timelines for Traditional, Lean, Fat, and Coast FIRE with safe withdrawal rates.

Estimate the hourly rate needed for an annual income target.

Estimate trip fuel use, cost, and per-person share.

Calculate a weighted grade point average from grades and credits.

Calculate PayPal, Stripe, and Square merchant processing fees, net payouts, and target invoice amounts.

Calculate prorated move-in and move-out rent using calendar days, 30-day banker rules, or annual daily rates.

Add sales tax to a price or work backward from a tax-inclusive total.

Count significant digits, round numbers, and perform arithmetic with sig fig precision rules.

Find the unit sales needed to cover fixed and variable costs.

Estimate monthly payments and total interest for a fixed-rate loan.

Project savings from a balance and recurring monthly contributions.

Calculate mean, median, mode, range, and quartiles with step-by-step explanations.

Calculate running pace, finish time, distance, and mile/km splits for any race.

Estimate daily resting and activity-adjusted calorie needs.

Estimate body fat using the U.S. Navy circumference method.

Calculate compound annual growth rate with inflation adjustments, interactive trajectory charts, reverse goal mode, and benchmarks.

Estimate monthly auto payments with trade-in equity, sales tax, fees, term comparison matrix, and extra principal payoff.

Estimate household emissions from driving and energy with disclosed EPA factors.

Transpose, add, or multiply small matrices with visible dimensions and validation.

Calculate time-and-a-half, double time, California daily overtime rules, FLSA weighted average rates, and take-home pay.

Estimate a due date from the first day of the last menstrual period.

Measure return on investment, annualized return, payback period, and digital marketing campaign ROAS with side-by-side comparison.

Convert an hourly rate into weekly, monthly, and annual pay.

Calculate interest without compounding.

Calculate sample and population standard deviation, variance, and mean with formulas.

Add or subtract hours and minutes without clock arithmetic.

Convert ordinary numbers to and from scientific notation.

Measure gain, loss, and percentage return on an investment.

Measure the time between two calendar dates.

Find sale price and savings after a percentage discount.

Convert numbers to Roman numerals and back, with each symbol explained.

Project investment growth with recurring compounding.

Estimate principal-and-interest payments for a fixed-rate mortgage.

Calculate concrete volume and bag count for slabs, footings, columns, and walls.

Convert grams to US cups and back for flour, sugar, butter and more.

Enter two names for a fun, honestly-labeled compatibility percentage (entertainment only, not a real test).

Scale a recipe up or down by servings or by a factor, with kitchen-friendly fractions and optional metric or US unit conversion.

Find exact age in years, months, and days from a birth date.

Answer the three most common percentage questions.

Convert length, weight, temperature, volume, and speed units.

Calculate a tip and split the total between people.

Calculate body mass index from height and weight.

Convert currencies with dated European Central Bank reference rates from the keyless Frankfurter API.