🧮 Free Online Calculators & Converters

45+ powerful tools for unit conversion, calculations, and measurements. Accurate, fast, and completely free.

45+

Free Tools

10

Categories

∞

Conversions

⚡

Physics & Engineering

10 tools

Pressure Conversion

Convert PSI, bar, atm, Pa, mmHg, and more

Power Conversion

Watts, horsepower, BTU/hr, and more

Speed Conversion

mph, km/h, m/s, knots, Mach

Torque Conversion

N·m, lb·ft, kg·cm, and more

Force Conversion

Newtons, pounds-force, dynes, kgf

Acceleration Conversion

m/s², ft/s², g-force, Gal

Energy Conversion

Joules, calories, BTU, kWh, eV

Density Conversion

kg/m³, g/cm³, lb/ft³, and more

Volume Conversion

Liters, gallons, cubic meters, cups

Weight & Mass

kg, pounds, ounces, tons, stones

📏

Length & Distance

4 tools

Length Conversion

Meters, feet, inches, miles, yards

Metric Length

mm, cm, m, km - metric system

Astronomical Units

Light years, parsecs, AU, km

Area Conversion

m², ft², acres, hectares, sq miles

💧

Viscosity

3 tools

Dynamic Viscosity

Pa·s, poise, cP, and more

Kinematic Viscosity

m²/s, Stokes, cSt, and more

Oil & Water Viscosity

SAE grades, API, water reference

🔌

Electrical & Frequency

5 tools

Electric Current

Amps, milliamps, microamps

Capacitance Conversion

Farads, µF, nF, pF

Ohm's Law Calculator

Voltage, current, resistance, power

Frequency Conversion

Hz, kHz, MHz, GHz, rpm

Flow Rate

L/min, GPM, m³/h, CFM

☀️

Light & Radiation

3 tools

Luminance Conversion

cd/m², nits, lamberts, foot-lamberts

Illuminance Conversion

Lux, foot-candles, phot, nox

Radioactivity

Becquerel, Curie, disintegrations

💻

Data & Computing

5 tools

Binary Data Storage

Bits, bytes, KB, MB, GB, TB, PB

Large Numbers Names

Million, billion, trillion to words

SI Prefix Converter

Kilo, mega, giga, nano, micro

HTML Color Picker

HEX, RGB, HSL color codes

ASCII Engine

Character codes, text encoding

💰

Financial Calculators

6 tools

Sales Tax Calculator

Calculate tax, total, pre-tax price

Income Calculator

Hourly, weekly, monthly, annual

Savings Calculator

Compound interest, growth

Tip Calculator

Tips, bill splitting, percentages

Employer Tax Calculator

Payroll taxes, employer costs

Paycheck Calculator

Net pay, deductions, taxes

⏰

Time Calculators

5 tools

Working Days Calculator

Business days between dates

Work Time Calculator

Hours worked, overtime

Time Card Calculator

Clock in/out, weekly hours

Time Zone Converter

Convert between time zones

Percentage Calculator

Percent of, increase, decrease

🔧

Other Useful Tools

4 tools

Cooking Conversions

Cups, tablespoons, grams, oz

Ring Size Conversion

US, UK, EU ring sizes, mm

Angle Conversion

Degrees, radians, gradians

Degrees ↔ Decimal

DMS to decimal degrees

Frequently Asked Questions

What types of calculators are available?

45+ free tools covering physics, engineering, finance, time, data, and everyday conversions. All tools are accurate and easy to use.

Are these calculators free to use?

Yes, completely free. No registration, no limitations. Use as many times as you need.

How accurate are the conversions?

Highly accurate. We use standard conversion factors from NIST and international standards. Results are precise to multiple decimal places.

Can I use these on mobile devices?

Yes. All calculators are fully responsive and work on phones, tablets, and desktops.

How do unit converters work?

Converters use mathematical conversion factors. Enter a value, select units, and the tool applies the correct formula instantly.

What is the most popular calculator?

Length, volume, and temperature converters are most popular, followed by financial calculators like tip and tax calculators.

Do you save my calculations?

No. All calculations happen in your browser. We don't store, track, or save any of your data.

Can I convert between metric and imperial?

Yes. Most converters support both metric (SI) and imperial/US customary units with instant bidirectional conversion.

What physics units can I convert?

Pressure, force, energy, power, torque, speed, acceleration, density, and more. Full SI and common engineering units.

How do I convert viscosity?

Use our dynamic or kinematic viscosity converters. Supports Pa·s, poise, Stokes, cSt, and industry-specific grades.

Do financial calculators handle taxes?

Yes. Sales tax, employer tax, and paycheck calculators include tax calculations for common scenarios.

Can I calculate time zones?

Yes. Time zone converter handles all major zones including DST. Also have working days and time card calculators.

What data/computing tools are available?

Binary storage, SI prefixes, ASCII, color picker, large numbers. Useful for developers, students, and IT professionals.

Are there cooking measurement tools?

Yes. Cooking conversions handle cups, tablespoons, teaspoons, grams, ounces, and ml for recipe adjustments.

How do I report a bug or suggest a tool?

Contact us through the website. We actively maintain tools and welcome suggestions for new calculators.

What electrical units can I convert?

Current, capacitance, frequency, flow rate. Plus Ohm's Law calculator for voltage, current, resistance, and power.

Are results suitable for professional use?

Yes. Our tools use standard conversion factors suitable for education, engineering, and professional applications. Always verify critical calculations.