Free online calculators
Our free online calculators cover everyday maths, finance, health, and science. Every calculator works instantly in your browser — no download, no account, no limits.
30 curated tools in this hub — open any card below, always free in your browser.
Tip Calculator
Calculate how much to tip and split the bill between any number of people. Free and instant.
Age Calculator
Calculate your exact age in years, months, days, hours, and minutes. Find out what day you were born on.
BMI Calculator
Calculate your Body Mass Index in imperial or metric units. See your BMI category, healthy weight range, and body fat estimate.
Calorie Calculator
Calculate your daily calorie needs (TDEE), BMR, and calorie targets for weight loss or gain. Includes macros calculator and food calorie lookup.
GPA Calculator
Calculate your semester GPA or cumulative GPA instantly using the standard 4.0 grade point scale.
Average Calculator
Calculate the mean, median, and mode of any set of numbers. Also shows sum, count, min, max, and range.
Median Calculator
Sort values and compute the median—even for even-length sets—for statistics and reporting.
Square Root Calculator
Evaluate √x, including perfect squares and irrationals, for geometry, signal processing, and homework.
Percentage Calculator
Calculate percentages, percentage change, and percentage difference instantly. Four calculation modes in one free tool.
Discount Calculator
Calculate the sale price after a discount, find the discount percentage, or reverse-calculate the original price. Free and instant.
Loan Calculator
Calculate monthly loan payments, total interest, and amortization schedules. Compare loans, model extra payments, and download CSV schedules.
Mortgage Calculator
Calculate monthly mortgage payments with taxes and insurance, check home affordability, compare refinance options, and view amortization schedules.
Compound Interest Calculator
Calculate compound interest growth with contributions, compare compounding frequencies, inflation adjustment, and year-by-year breakdowns.
Sales Tax Calculator
Add or remove sales tax from any price. Includes all 50 US state tax rates. Free and instant.
Markup Calculator
Compute selling price, cost, or markup percentage for retail pricing and margin planning.
Overtime Calculator
Estimate gross pay with regular and overtime hourly rates based on hours worked in a week.
Fuel Cost Calculator
Calculate gas costs for any trip, monthly commute costs, and compare fuel costs between two vehicles including EVs.
Sleep Calculator
Find ideal bedtimes or wake-up times using 90-minute sleep cycles so you wake between cycles, not during deep sleep.
Pace Calculator
Calculate running pace, finish time, or distance from any two values. Supports km and miles with 5K, 10K, half marathon, and marathon presets.
Electricity Cost Calculator
Estimate daily, monthly, and annual electricity cost from device watts, hours of use, and your kWh rate. Free appliance cost estimator.
Retirement Calculator
Project retirement savings with monthly contributions, inflation-adjusted value, and estimated monthly income using the 4% withdrawal rule.
Invoice Generator
Create professional invoices with logo, line items, taxes, and payment details. Download as PDF. Save up to 20 invoices. Free, no signup.
Proportion Calculator
Solve for unknowns in ratios (a/b = c/d) for recipes, scaling blueprints, and similar triangles.
Velocity Calculator
Relate displacement, time, and constant velocity—or derive average speed—from trip segments.
Percent Error Calculator
Compare experimental vs theoretical values to quantify accuracy in labs and calibration tasks.
Significant Figures Calculator
Round results to the correct count of sig figs after multiply/divide or add/subtract operations.
Scientific Notation Calculator
Normalize very large or small numbers to a × 10ⁿ form for chemistry, physics, and engineering.
Scientific Calculator
Full-featured scientific calculator with trig functions, logarithms, powers, memory, expression history, and programmer mode. Keyboard support included.
Weighted Grade Calculator
Calculate your weighted average grade from percentage scores and category weights (homework, exams, final, etc.). Add rows, see letter grade and rough 4.0 mapping — free, instant.
Syllable Counter
Estimate syllables per word or line for poetry, readability scoring, and speech pacing.
Calculators — frequently asked questions
Yes. Every calculator in this hub is free with no signup, no trial limits, and no paywall. Open any tool card, enter your numbers, and get instant results in your browser.
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