Free Online Calculators

We calculate, you create — 30+ free tools for construction, finance, health, dates and math. Simple, accurate, and ready to use.

Explore Tools

CommunityCalculator is a free set of 34 calculators and 50 unit converters for construction, finance, health, maths and time. Every tool runs entirely in your browser, shows the formula it applies, and works without an account — nothing you type is sent to a server.

Built and reviewed by the AxeConstruct engineering team · Last updated · How these calculators are built

Free Tools

Our Calculators

Browse our collection of precision tools designed to help you solve problems faster.

🏗️ Construction & Measurement

Cubic yard calculator icon

Cubic Yard Calculator

Calculate volume for concrete, mulch, gravel, and more. Includes bag calculator.

Open Tool
Concrete calculator icon

Concrete Calculator

Estimate concrete slabs, footings, and walls with precision. Cost estimation included.

Open Tool
Asphalt calculator icon

Asphalt Calculator

Calculate hot mix asphalt tonnage for driveways and paving projects.

Open Tool
Square footage calculator icon

Square Footage

Calculate area in square feet for flooring, painting, and construction.

Open Tool
Unit converter icon

Unit Converter

Convert quickly: Length, Area, Volume, Mass, Pressure, and more.

Open Tool
Map area calculator icon

Map Tools

Measure areas, distances, and perimeters directly on a map.

Open Tool
Quadratic solver icon

Quadratic Solver

Solve quadratic equations and find roots instantly.

Open Tool
Factoring calculator icon

Factoring Calculator

Factor polynomials and expressions step by step.

Open Tool
Polynomial calculator icon

Polynomial Calculator

Simplify, add, and multiply polynomial expressions.

Open Tool
Parabola graph calculator icon

Parabola Graph Calculator

Plot parabolas and find vertex, axis, and roots.

Open Tool
Feet converter icon

Feet Converter

Convert feet to meters, inches, cm, and more.

Open Tool

📅 Time & Dates

Date calculator icon

Date Calculator

Calculate duration between dates or add/subtract days from a date.

Open Tool
Age calculator icon

Age Calculator

Calculate exact age, chronological age, and time until next birthday.

Open Tool
Time calculator icon

Time Calculator

Add hours, calculate work duration, and estimate costs with hourly rates.

Open Tool
Distance calculator icon

Distance Calculator

Calculate distance between two coordinates or cities on a map.

Open Tool
Half birthday calculator icon

Half Birthday

Find out exactly when your half-birthday occurs.

Open Tool
Countdown timer icon

Countdown Timer

Create a customized countdown for your upcoming events.

Open Tool

💰 Finance & Calculations

Loan calculator icon

Loan Calculator

Estimate monthly payments, total interest, and amortization schedules.

Open Tool
Percentage calculator icon

Percentage Calc

Easy calculations for percentage increase, decrease, and parts of a whole.

Open Tool
Four function calculator icon

4 Function Calculator

Add, subtract, multiply and divide, with percent and memory keys.

Open Tool
Scientific calculator icon

Scientific Calculator

Advanced mathematical functions including trig, log, and exponents.

Open Tool
Cute calculator icon

Cute Calculator

A kawaii pastel calculator with a cat mascot, dark mode and 6 modes.

Open Tool
Retirement savings calculator icon

How Long Will My Money Last

See exactly when your savings run out, with inflation, returns and pension income.

Open Tool
Invoice generator icon

Invoice Generator

Create professional PDF invoices for your business in seconds.

Open Tool
Crypto converter icon

Crypto Converter

Real-time cryptocurrency conversion for Bitcoin, Ethereum, and more.

Open Tool

❤️ Health & Lifestyle

BMI calculator icon

BMI Calculator

Calculate Body Mass Index based on height and weight.

Open Tool
Calorie calculator icon

Calorie Calculator

Estimate daily caloric needs for weight loss, gain, or maintenance.

Open Tool
Blood pressure MAP calculator icon

BP MAP Calculator

Calculate your Mean Arterial Pressure (BP) for cardiovascular health.

Open Tool

📚 Guides & Reviews

Smart calculator guide

What Makes a Calculator Smart

CAS, graphing, QR code and AI photo solvers compared — which one you need...

Read Article
Texas Instruments Calculator

Texas Instruments Complete Guide

Learn how to do fractions, charge, and use the TI-84 Plus CE effectively...

Read Article
Cute Calculator Aesthetics

Top Cute Calculators in 2026

Discover the best cute, pink, and aesthetic calculators for your desk...

Read Article
3D Printing Cost Calculator

3D Printing & Office Calculators

How to calculate the cost of 3D printing and the best office printing tools...

Read Article

Frequently asked questions

Are the calculators on CommunityCalculator free?

Yes. All 34 calculators and 50 unit converters are free and need no account. There is no trial, no paywall and no signup step before you get a result.

Is my data sent to a server?

No. Every calculation runs in your browser, so nothing you type leaves your device. The only exception is the cryptocurrency converter, which requests a live exchange rate; that request contains no personal data.

Do the calculators work offline?

Yes, once a page has loaded. Because the formula is written into the page itself, a calculator keeps working if your connection drops. Only the live crypto rates need a connection.

Where do the conversion factors come from?

They are the internationally agreed exact definitions: one inch is exactly 2.54 cm, one foot exactly 0.3048 m, one pound exactly 0.45359237 kg, one acre exactly 43 560 square feet. These are defined values, so the conversion is exact.

Who publishes CommunityCalculator?

CommunityCalculator is published by AxeConstruct, a developer of digital solutions for engineering and construction. The calculators are built and reviewed by its engineering team.

More about how these tools are built, and their limits, on the about page.

How these calculators are built

Every calculator on this site is a single page that carries its own formula. The maths runs in your browser, in JavaScript, and the result appears without a round trip to a server. That has three consequences worth stating plainly: the tools keep working when your connection drops, we hold no record of anything you type, and there is no account to create before you get a number. The one exception is the cryptocurrency converter, which has to request a live exchange rate — that request carries no personal data.

Why is the formula always shown?

A calculator that returns only a number is impossible to check. Each tool states the formula it applies and works through at least one example with real figures, so you can verify the result by hand or understand why it differs from another source. The mean arterial pressure calculator, for instance, explains why the diastolic reading is doubled rather than simply averaged with the systolic one — at rest the heart spends roughly twice as long in diastole as in systole.

Where do the conversion factors come from?

Unit conversions use the internationally agreed exact definitions rather than approximations copied from other sites: one inch is exactly 2.54 centimetres, one foot exactly 0.3048 metres, one pound exactly 0.45359237 kilograms, one acre exactly 43 560 square feet, one cubic yard exactly 27 cubic feet. These are defined values, not measured ones, so the conversion itself is exact and only the rounding introduces error. Where a factor shown on a page is rounded, the page says so and gives the exact definition behind it.

Which calculator should you use?

The tools fall into five groups. Construction and measurement covers cubic yards, concrete, asphalt, square footage and feet and inches — the estimating work that comes out of day-to-day engineering practice. Maths covers the scientific calculator, quadratic, polynomial, factoring and percentages. Time and dates covers date differences, age, durations and countdowns. Finance covers loan repayment, invoices and crypto rates. Health covers BMI, calories and mean arterial pressure.

Are the health calculators medical advice?

No. The BMI, calorie and mean arterial pressure tools apply published formulas and the classification ranges used by the World Health Organization, the NIH and the American Heart Association. They are there to let you reproduce a number and understand how it was reached, not to diagnose anything. Any reading that concerns you belongs with a clinician, not a web page.