Free Online Calculators & Converters

10 essential tools for finance, health, and everyday life. No sign-up, no data stored, instant results.

✓ 100% Free ✓ No registration ✓ No data stored ✓ Mobile friendly

Finance Calculators

Calculate salaries, taxes, loans, and investment returns.

Salary Calculator

Convert net to gross salary. Full breakdown of income tax and social contributions.

VAT / Tax Calculator

Add or remove VAT from any price. Supports all countries and all VAT rates.

Percentage Calculator

5 modes: find X% of Y, percentage change, discounts, markups and more.

Loan Calculator

Monthly payments, total interest, and full cost breakdown for any loan.

Compound Interest Calculator

See how investments grow with compound interest and monthly contributions.

Mortgage Calculator

Monthly payment, total interest, and full cost breakdown for any home loan.

Currency Converter

Live exchange rates for 30+ world currencies. Updated daily.

Unit Converters

Convert between units used around the world.

KG to LBS Converter

Convert kilograms to pounds and back. Also shows stones, grams, and ounces.

Celsius to Fahrenheit

Instant temperature conversion between °C, °F, Kelvin, and Rankine.

Date & Time Tools

Calculate ages, durations, and time between dates.

Exact age in years, months, days, and hours. Shows next birthday countdown.

Time Duration Calculator

Calculate the duration between any two dates and times in all units.

Security Tools

Stay safe online with strong, random passwords.

Password Generator

Generate cryptographically secure passwords up to 64 characters. Browser-based, nothing stored.

About CalcTools

CalcTools is a collection of free, fast, and accurate online calculators and converters. Every tool works directly in your browser — no account required, no data collected, no cookies tracking you.

Our tools are designed to be genuinely useful: clear inputs, instant results, and plain-English explanations so you understand not just the answer but how it was calculated. Whether you are checking a salary offer, working out tax on an invoice, planning a loan, or converting units for a recipe, CalcTools gives you accurate results in seconds.

All calculators use standard mathematical formulas verified against official sources. For legal, financial, or medical decisions, always verify results with a qualified professional.