All calculators
118 tools online. Each page shows inputs, formula, and a worked example.
No calculators matched.
Percentage Calculator
Find X% of a number, or what percent one number is of another.
Percent Change Calculator — % Increase Formula
Percent increase or decrease between two values.
Average Calculator
Arithmetic mean of a comma-separated list of numbers.
Ratio Calculator
Simplify a:b and scale a ratio to a target total.
Square Root Calculator (√x)
Principal square root of a non-negative number.
Circle Area Calculator
Area and circumference from radius.
Triangle Area Calculator
Area from base and height.
Pythagorean Theorem Calculator — Find Missing Side
Find the missing side of a right triangle.
BMI Calculator
Body Mass Index from height and weight (metric).
BMR Calculator
Basal metabolic rate (Mifflin–St Jeor).
Ideal Weight Calculator
Devine formula ideal body weight.
Tip Calculator
Split a bill with tip across any number of people.
Compound Interest Calculator
Future value with compound interest.
Loan Payment Calculator
Fixed monthly payment for an amortizing loan.
Mortgage Calculator
Monthly payment for a fixed-rate mortgage.
Simple Interest Calculator
Interest and total with I = Prt.
Discount Calculator
Sale price after a percent discount.
Sales Tax Calculator
Add sales tax to a net price.
ROI Calculator
Return on investment as a percent.
Length Converter
Convert between meters, centimeters, feet, and inches.
Weight Converter
Convert between kilograms and pounds.
Celsius to Fahrenheit Converter
Convert Celsius, Fahrenheit, and Kelvin.
Speed Converter
Convert km/h and mph.
Age Calculator
Exact age from a birth date.
Days Between Dates Calculator
Whole days between two calendar dates.
Simplify Fractions Calculator — Formula + Examples
Simplify a fraction and convert it to a decimal.
GCF & LCM Calculator
Greatest common factor and least common multiple of two integers.
Factorial Calculator
n! for non-negative integers up to 170.
Exponent Calculator
Raise a base to a power (aᵇ).
Log Calculator — Natural, Common & Any Base
log base b of x, plus natural and common logs.
Rectangle Area Calculator
Area and perimeter of a rectangle.
Cylinder Volume Formula (V = πr²h) — Free Calculator
Volume and lateral surface area of a right cylinder.
Sphere Volume Calculator
Volume and surface area of a sphere.
Median Calculator for a Number List
Median of a comma-separated list of numbers.
Proportion Calculator — Rule of Three (a/b = c/x)
Solve a/b = c/x (rule of three).
VAT Calculator
Add or remove value-added tax.
Retail Markup & Selling Price Calculator
Selling price from cost and markup percent.
Inflation Calculator
Future or past purchasing power with compound inflation.
Salary to Hourly Calculator
Convert annual salary to an hourly rate.
Present Value Calculator
Discount a future lump sum to today.
Break-Even Calculator
Units needed to cover fixed and variable costs.
TDEE Calculator
Total daily energy expenditure from BMR × activity.
Body Fat Calculator
US Navy body fat estimate from tape measurements.
Pregnancy Due Date Calculator
Estimated due date from last menstrual period (Naegele).
Macro Calculator
Split daily calories into protein, carbs, and fat grams.
Running Pace Calculator
Pace per km or mile from distance and time.
Volume Converter
Convert liters, milliliters, gallons (US), and cups.
Area Converter
Convert m², ft², acres, and hectares.
Data Storage Converter
Convert KB, MB, GB, and TB (decimal, 1000-based).
Add Days to a Date Calculator
Add or subtract days from a calendar date.
Quadratic Formula Calculator
Solve ax² + bx + c = 0 for real roots.
Standard Deviation Calculator (Sample & Population)
Sample or population standard deviation of a list.
Permutation & Combination Calculator (nPr, nCr)
nPr and nCr for choosing r items from n.
Decimal to Fraction Calculator
Convert a decimal to a simplified fraction.
Cone Volume Calculator
Volume and lateral area of a right circular cone.
Cube Volume Calculator
Volume and surface area of a cube.
Slope Calculator — m Between Two Points
Slope of a line through two points.
Percent Difference Calculator — Free Formula Tool
Percent difference relative to the average of two values.
Future Value of a Lump Sum Calculator
Grow a present lump sum with compound interest.
Gross Profit & Margin Percent Calculator
Gross profit and margin from cost and selling price.
Commission Calculator
Sales commission from rate and sales amount.
Hourly to Salary Calculator
Convert hourly wage to annual salary.
Debt Payoff Calculator
Months to pay off a balance with fixed monthly payments.
Depreciation Calculator
Straight-line depreciation per year.
Ovulation Calculator & Fertile Window
Estimate ovulation day and fertile window from LMP.
Daily Water Intake Calculator by Weight
Rough daily water goal from body weight.
Heart Rate Zone Calculator
Training zones from age using max HR ≈ 220 − age.
One-Rep Max Calculator
Estimate 1RM from weight and reps (Epley).
Waist-Hip Ratio Calculator
Waist ÷ hip circumference ratio.
Pressure Converter
Convert Pa, kPa, bar, psi, and atm.
Energy Converter
Convert J, kJ, cal, kcal, and kWh.
Watts to Horsepower & kW Converter
Convert W, kW, HP, and BTU/h.
Hours to Days & Minutes Converter
Convert seconds, minutes, hours, and days.
Business Days Between Two Dates Calculator
Count weekdays between two dates (Mon–Fri).
What Day of the Week Calculator
Find which weekday a calendar date falls on.
Midpoint Calculator
Midpoint of a line segment between two points.
Distance Formula Calculator
Euclidean distance between two 2D points.
Trapezoid Area Calculator
Area of a trapezoid from two bases and height.
Circle Circumference Calculator
Circumference and diameter from radius.
Variance Calculator
Sample or population variance of a list.
Z-Score Calculator
Standard score (x − μ) / σ.
Scientific Notation Calculator
Convert a number to a × 10ⁿ form.
Percentage Error Calculator
Percent error vs an accepted (true) value.
Savings Goal Calculator
Monthly deposit needed to reach a savings target.
Down Payment Calculator
Down payment dollars and loan amount from price and %.
Rental Yield Calculator
Gross and net rental yield from rent and property price.
APY Calculator
Convert nominal APR to APY with compounding.
Cashback Calculator
Cashback earned from spend and cashback rate.
Net Worth Calculator
Assets minus liabilities.
Auto Loan Calculator
Monthly payment for a car loan after down payment.
Mortgage Refinance Calculator
Compare current vs new payment and break-even months.
Amortization Calculator
Payment, total interest, and first-month split.
House Affordability Calculator
Max home price from income, debts, rate, and down %.
Debt-to-Income Calculator
DTI ratio from monthly debts and income.
Retirement Calculator
Future nest egg from savings and monthly contributions.
CAGR Calculator
Compound annual growth rate between two values.
Rule of 72 Calculator
Years to double (or rate needed) with Rule of 72.
Annuity Calculator
Future value of regular deposits (ordinary annuity).
Biweekly Mortgage Calculator
Half-payment every two weeks vs monthly schedule.
Student Loan Calculator
Fixed monthly payment for a student loan.
Paycheck Calculator
Estimate take-home pay from gross and tax %.
Capital Gains Calculator
Gain/loss and estimated tax from a sale.
SIP Calculator
Future value of a monthly SIP investment.
EMI Calculator
Equated monthly installment for a loan.
GST Calculator
Add or remove Goods and Services Tax.
CD Calculator
Certificate of deposit maturity value.
Loan APR Calculator
Effective APR when upfront fees reduce cash received.
Calories Burned Calculator
Estimate calories from MET, weight, and duration.
Body Surface Area Calculator
BSA with the Mosteller formula.
Lean Body Mass Calculator
Estimate LBM from weight and body-fat %.
Sleep Cycle Calculator
Suggested wake times from bedtime (90-min cycles).
Protein Intake Calculator
Daily protein target from weight and activity.
Angle Converter
Convert degrees, radians, and gradians.
Fuel Economy Converter
Convert mpg (US), mpg (UK), and L/100 km.
Newton to Pound-Force Converter
Convert N, kN, lbf, and kgf.
Frequency Converter
Convert Hz, kHz, MHz, and GHz.
Week Number Calculator
ISO week number for a calendar date.
Unix Timestamp Converter
Convert Unix epoch seconds ↔ calendar datetime (UTC).