Calculate anything.
Know the answer.
Fast, free calculators for work, money, home projects and everyday life. Get a clear answer in seconds — with the formula and assumptions shown.
Recently used
Popular starting points
Start with the tools people use for real work, projects, money decisions and everyday calculations.
Work Hours Calculator
Calculate hours worked from start time, finish time and unpaid breaks.
Calculate →Home & DIYConcrete Calculator
Estimate concrete volume and premix bag quantity for a rectangular pour.
Calculate →Home & DIYPaint Calculator
Estimate litres of wall paint based on room dimensions, openings, coats and coverage.
Calculate →Business & SellingProfit Margin Calculator
Calculate profit, gross margin and markup from cost and selling price.
Calculate →Math & EverydayPercentage Calculator
Calculate a percentage of a number, or what percent one number is of another.
Calculate →MoneyCompound Interest Calculator
Estimate future value with recurring compounding.
Calculate →ConvertersLength Converter
Convert metres, kilometres, feet, inches, yards and miles.
Calculate →Math & EverydayFuel Cost Calculator
Estimate trip fuel use and cost from distance and fuel economy.
Calculate →Home & DIYDeck Board Calculator
Estimate deck board quantity from deck size, board dimensions, spacing and waste.
Calculate →Built to be useful first
Answer immediately
The calculator appears before long explanatory text. Users can get the result first and read the method second.
Show the working
Each page includes the formula, assumptions, example and caveats instead of hiding how the number was produced.
Designed for expansion
Category architecture, internal links, sitemap and reusable calculation code make it practical to grow from launch tools into a much larger library.
Work & Time
Track shifts, hours, pay and dates.
Work Hours Calculator
Calculate hours worked from start time, finish time and unpaid breaks.
Calculate →Work & TimeOvertime Pay Calculator
Estimate regular pay, overtime pay and total gross pay.
Calculate →Work & TimeTimesheet Calculator
Add up a five-day timesheet with daily start, finish and break times.
Calculate →Work & TimeShift Length Calculator
Find the duration of a shift, including overnight shifts and breaks.
Calculate →Work & TimeTime Between Times Calculator
Find elapsed hours and minutes between two clock times.
Calculate →Work & TimeBusiness Days Calculator
Count Monday-to-Friday weekdays between two dates.
Calculate →Home & DIY
Estimate materials, areas and project quantities.
Concrete Calculator
Estimate concrete volume and premix bag quantity for a rectangular pour.
Calculate →Home & DIYConcrete Slab Calculator
Estimate cubic metres of concrete for a slab with waste allowance.
Calculate →Home & DIYSquare Footage Calculator
Calculate rectangular area in square feet and square metres.
Calculate →Home & DIYPaint Calculator
Estimate litres of wall paint based on room dimensions, openings, coats and coverage.
Calculate →Home & DIYGravel Calculator
Estimate gravel volume and approximate weight for paths and landscaping.
Calculate →Home & DIYMulch Calculator
Work out cubic metres and litres of mulch for beds and borders.
Calculate →Business & Selling
Price, margin, fees, advertising and break-even tools.
Profit Margin Calculator
Calculate profit, gross margin and markup from cost and selling price.
Calculate →Business & SellingMarkup Calculator
Calculate selling price from cost and target markup.
Calculate →Business & SellingBreak-Even Calculator
Calculate break-even units and approximate revenue.
Calculate →Business & SellingDiscount Calculator
Calculate sale price and savings from a percentage discount.
Calculate →Business & SellingVAT Calculator
Add or remove a user-entered VAT percentage.
Calculate →Business & SellingSales Tax Calculator
Calculate sales tax and total using your own tax rate.
Calculate →Money
Interest, loans, savings and payment estimates.
Compound Interest Calculator
Estimate future value with recurring compounding.
Calculate →MoneySimple Interest Calculator
Calculate simple interest and final balance.
Calculate →MoneyLoan Payment Calculator
Estimate fixed monthly repayments for an amortising loan.
Calculate →MoneyMortgage Payment Calculator
Estimate principal-and-interest mortgage payments from amount, rate and term.
Calculate →MoneySavings Goal Calculator
Estimate monthly saving needed to reach a target with optional annual growth.
Calculate →MoneyDebt Payoff Calculator
Estimate payoff time and interest for a fixed monthly payment.
Calculate →Math & Everyday
Percentages, dates, fuel, travel and everyday maths.
Percentage Calculator
Calculate a percentage of a number, or what percent one number is of another.
Calculate →Math & EverydayPercentage Change Calculator
Calculate percentage increase or decrease between two values.
Calculate →Math & EverydayPercentage Difference Calculator
Calculate symmetric percentage difference between two values.
Calculate →Math & EverydayAverage Calculator
Calculate the arithmetic mean of a list of numbers.
Calculate →Math & EverydayRatio Simplifier
Simplify a two-number ratio to lowest whole-number terms.
Calculate →Math & EverydayAge Calculator
Calculate age in years, months and days from a birth date.
Calculate →Converters
Fast unit conversions for common measurements.
Length Converter
Convert metres, kilometres, feet, inches, yards and miles.
Calculate →ConvertersWeight Converter
Convert kilograms, grams, pounds, ounces and stone.
Calculate →ConvertersTemperature Converter
Convert Celsius, Fahrenheit and Kelvin.
Calculate →ConvertersArea Converter
Convert square metres, square feet, acres and hectares.
Calculate →ConvertersVolume Converter
Convert litres, millilitres, cubic metres, US gallons and Imperial gallons.
Calculate →ConvertersSpeed Converter
Convert km/h, mph, metres/second and knots.
Calculate →Built to grow with what people need
NUMTX is designed as a focused utility library. New tools should solve genuine calculation problems and expand the categories visitors actually use.
Find answers faster
Search the library, jump between related tools and get straight to the calculation you need.
More useful tools
NUMTX can keep expanding around practical problems while keeping every calculator simple and transparent.
Free to use
The core calculators are designed to stay quick and accessible without signup walls getting between you and the answer.