Free Unit Converter Tools Fast, Accurate, Privacy First

Top, Fast, Best, and Lifetime Free Unlimited. Convert metric ↔ imperial in seconds: cm↔in, kg↔lb, °C↔°F, mph↔km/h, L↔gal, and more. Works worldwide. No signup. Your information is 100% confidential and secure.

Length Unit Converter

Convert mm, cm, m, km ↔ in, ft, yd, mi instantly. Includes metre/meter and kilometre/kilometer for UK/US variants.

Area Unit Converter

Convert m², cm², km² ↔ ft², yd², acres, hectares. Great for real estate, farming, and construction.

Data Transfer Rate Unit Converter

Convert bps, Kbps, Mbps, Gbps ↔ B/s, KB/s, MB/s. Clarifies Mbps vs MB/s for internet speed testing.

Digital Storage Unit Converter

Convert bit/byte, KB, MB, GB, TB and binary units (KiB, MiB, GiB). Perfect for disk sizes and file storage.

Energy Unit Converter

Convert J, kJ, kWh, cal, kcal, BTU. Ideal for electricity, nutrition, and HVAC calculations.

Frequency Unit Converter

Convert Hz, kHz, MHz, GHz. Useful for audio, electronics, and RF work.

Fuel Economy Unit Converter

Convert L/100 km, km/L, MPG (US & UK). Great for car mileage comparisons worldwide.

Mass Unit Converter

Convert mg, g, kg ↔ oz, lb, stone, tonne. Popular: kg to lbs, stone to kg (UK).

Plane Angle Unit Converter

Convert degrees, radians, gradians, and mils. Ideal for math, surveying, and navigation.

Pressure Unit Converter

Convert Pa, kPa, MPa, bar, atm, psi, torr. Popular: psi to bar, bar to kPa.

Temperature Unit Converter

Convert Celsius, Fahrenheit, Kelvin. Popular: °C ↔ °F (US/Canada/India).

Speed Unit Converter

Convert m/s, km/h, mph, knots. Popular: km/h ↔ mph (UK/US) and knots for aviation/marine.

Time Unit Converter

Convert ns, ms, s, min, hr, day, week, month, year. Precise for computing and schedules.

Volume Unit Converter

Convert mL, L, cup, pint, quart, gallon (US/UK), and m³. Popular: liters ↔ gallons (US & Imperial).

Free Unit Converter Tools Fast, Accurate, Privacy First

Convert length (cm↔in, m↔ft, km↔mi), mass (kg↔lb, stone↔kg), temperature (°C↔°F↔K), speed (km/h↔mph, m/s, knots), volume (L↔gal US & UK, mL↔cup), area (m²↔ft², acre↔hectare), pressure (bar↔psi↔kPa↔atm), energy (J↔kWh↔cal↔BTU), frequency (Hz↔kHz↔MHz↔GHz), time, digital storage (KB↔MB↔GB↔TB, KiB↔MiB↔GiB), and data rates (Mb/s↔MB/s).

Top, Fast, Best & Lifetime Free Unlimited. No signup. Works worldwide on mobile and desktop. Your information is 100% confidential and secure.

How to use

  1. Select the unit converter you need (e.g., Length, Mass, Temperature).
  2. Enter a value and choose your input and output units.
  3. View the result instantly; adjust precision if needed.

Popular conversions

  • cm to inches / inches to cm
  • meters to feet / feet to meters (metre↔meter)
  • km to miles / miles to km
  • kilograms to pounds / pounds to kg
  • stone to kg (UK)
  • °C to °F / °F to °C / °C to K
  • km/h to mph / mph to km/h
  • liters to gallons (US) / liters to gallons (UK)
  • bar to psi / psi to kPa
  • J to kWh / kcal to kJ / BTU to kWh
  • MB to GB / GiB to GB
  • Mb/s to MB/s (internet speed)

Regional variants supported: litre/liter, metre/meter, US/UK (Imperial) gallon, kPa/psi (Canada/US), stone (UK/IE), mph↔km/h (US/UK/EU/Australia), A4/Letter sizes where applicable.

Frequently asked questions

Are the unit converters free and unlimited?

Yes. Top, Fast, Best & Lifetime Free Unlimited. No signup required.

Do you support metric and imperial/US/UK units?

Yes. Metre/meter, litre/liter, US & UK gallons, stone, miles, yards, feet, inches, and more.

Is my information private and secure?

Yes. Inputs are processed securely; we do not store your personal calculation data.

Do the tools work on mobile?

Yes. Optimized for mobile and desktop across major browsers. Works worldwide.

Which conversions are included?

Length, area, mass, temperature, speed, volume, pressure, energy, frequency, time, digital storage, and data rates.

How accurate are results?

We use standard conversion factors with clear rounding and optional precision controls.