OmniCalc
38 free calculators and converters that run instantly in your browser. No sign up. No ads following you around. No data ever leaves your device.
Finance
Compound Interest Calculator
Project how your savings or investments grow over time with compound interest.
Open toolLoan Payment Calculator
Calculate your monthly payment, total cost, and total interest for any loan.
Open toolSavings Goal Calculator
Find out how much you need to save each month to reach a financial goal.
Open toolTip Calculator
Calculate the tip and split the bill between any number of people.
Open toolMortgage Calculator
Estimate your full monthly mortgage payment including principal, interest, property tax, and insurance.
Open toolSalary to Hourly Calculator
Convert an annual salary to hourly, weekly, and monthly pay, or an hourly wage to annual salary.
Open toolSales Tax Calculator
Add sales tax to a price, or work backward from a total to find the pre-tax price and tax paid.
Open toolDiscount Calculator
Calculate the sale price and amount saved from any percentage discount, including stacked discounts.
Open toolRetirement Savings Calculator
Project your retirement balance and the annual income it could support under the 4 percent rule.
Open toolDebt Payoff Calculator
Find out how long it will take to pay off a credit card or loan and how much interest you will pay.
Open toolSimple Interest Calculator
Calculate simple interest and total repayment for loans that do not compound.
Open toolMath
Percentage Calculator
Solve any percentage problem: percent of a number, percent ratio, and percent change.
Open toolNumber Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
Open toolFraction Calculator
Add, subtract, multiply, and divide fractions with automatically simplified results.
Open toolAverage Calculator
Calculate mean, median, mode, range, and standard deviation from any list of numbers.
Open toolGPA Calculator
Calculate your grade point average on the standard 4.0 scale from letter grades and credit hours.
Open toolHealth
BMI Calculator
Calculate your Body Mass Index in metric or imperial units and see your category.
Open toolCalorie Calculator
Estimate your daily calorie needs (BMR and TDEE) using the Mifflin-St Jeor equation.
Open toolBody Fat Calculator
Estimate body fat percentage from tape measurements using the US Navy method.
Open toolPregnancy Due Date Calculator
Estimate your due date from the first day of your last period, with current week and trimester.
Open toolIdeal Weight Calculator
Estimate ideal body weight from height using four standard medical formulas plus the healthy BMI range.
Open toolWater Intake Calculator
Estimate how much water you should drink per day based on body weight and exercise.
Open toolRunning Pace Calculator
Calculate your running pace per kilometer and per mile, plus speed and race projections.
Open toolUtilities
Password Generator
Generate strong, random passwords securely in your browser. Nothing is sent anywhere.
Open toolRandom Number Generator
Generate one or many random numbers in any range, with or without duplicates, using a secure source.
Open toolBase64 Encoder and Decoder
Encode text to Base64 or decode Base64 back to text, entirely in your browser with full Unicode support.
Open toolRoman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers, from 1 to 3999.
Open toolWriting
Conversion
Length Unit Converter
Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles.
Open toolTemperature Converter
Convert between Celsius, Fahrenheit, and Kelvin instantly.
Open toolWeight Converter
Convert between kilograms, grams, pounds, ounces, stone, and tonnes.
Open toolSpeed Converter
Convert between kilometers per hour, miles per hour, meters per second, knots, and feet per second.
Open toolArea Converter
Convert between square meters, square feet, acres, hectares, and other area units.
Open toolVolume Converter
Convert between liters, milliliters, gallons, cups, fluid ounces, and other volume units.
Open toolData Storage Converter
Convert between bits, bytes, KB, MB, GB, TB and their binary counterparts KiB, MiB, GiB, TiB.
Open toolDate & Time
Why OmniCalc
Every tool on this site is built to do one job quickly and accurately. There are no accounts to create, no downloads, and no paywalls. All calculations run locally in your browser using standard, documented formulas, so your numbers, text, and dates are never transmitted to a server.
The collection covers the calculations people reach for most: loan payments and compound interest for financial decisions, BMI and daily calorie needs for health planning, unit and temperature conversion for work and travel, and everyday utilities like password generation and word counting. Each tool page explains the formula it uses and answers the most common questions about it.