Unit Converter

Enter a number. Scientific notation is supported (e.g., 1e-3).
Note: 1 KiB = 1024 bytes; 1 KB = 1000 bytes. For energy, 1 cal = 4.184 J and 1 kWh = 3.6 MJ.

From a quick miles to km check to advanced engineering values, this Unit Converter removes the friction from everyday maths. It’s simple, accurate, and built around the high-value conversions people search for most—Miles to Kilometres, Pounds to Kilograms, Inches to Centimetres, Litres to Gallons, Fahrenheit to Celsius, PSI to Bar, Watts to Horsepower, BTU to kWh, and more.

Bookmark it once and you’ll reach for it every time you need a fast, trustworthy answer.

The Ultimate Unit Converter: Fast, Accurate, and Built for Real-World Use

Looking for a reliable Unit Converter you can trust every day? Whether you need a quick Miles to Kilometers converter for a road trip, an inches to centimetres check while shopping online, or engineering-grade PSI to bar and BTU to kWh calculations, this tool makes conversions instant, precise, and frustration-free. It’s designed for both casual users and professionals, with clean controls, a “swap units” button, copy-to-clipboard, and a precision selector so results look exactly the way you want.

Conversions You Can Do in Seconds

Our converter covers the most searched conversions plus specialist units used worldwide. Here’s a tour of what’s included.

Miles to Kilometres (and Kilometres to Miles)

The headline act: a streamlined Miles to Kilometres converter (mi to km) and km to miles in one click. Perfect for comparing US and UK/European distances, planning runs, or reading international maps. One mile is 1.609344 km, and we use that exact constant so you get dependable results every time.

Length & Distance

Convert everyday and technical distances with confidence:

  • metres ↔ feet, centimetres ↔ inches, millimetres ↔ inches (thou/mils)
  • yards ↔ metres, nautical miles ↔ kilometres
  • Scientific units too: ångström (Å), micrometre (µm)

Ideal for DIY, textiles, 3D printing, surveying, and navigation.

Weight / Mass

From the gym to gemstones, it’s got you covered:

  • pounds (lb) ↔ kilograms (kg), ounces (oz) ↔ grams (g)
  • stones (st) for UK users
  • tonnes (t), US short tons, Imperial long tons
  • troy ounces (ozt) for precious metals, carats (ct) for gems

Temperature

Cook, calibrate, or check the forecast with instant Celsius (°C) ↔ Fahrenheit (°F) and Kelvin conversions. The tool uses the exact formulas (no rounding shortcuts), so scientific and culinary results are spot-on.

Volume & Cooking

Switch between metric and US/Imperial kitchen measures without guessing:

  • litres (L) ↔ gallons (US & UK/Imperial)
  • millilitres (mL) ↔ fluid ounces (US/Imperial)
  • cups, tablespoons, teaspoons (metric and US)
  • cubic metres/feet/inches for storage, shipping, and aquariums

Area

Estate agents, gardeners, and designers love these:

  • square metres ↔ square feet, square yards ↔ square metres
  • acres ↔ hectares, square kilometres

Speed

Ideal for motorists and aviators:

  • miles per hour (mph) ↔ kilometres per hour (km/h)
  • knots ↔ km/h or mph
  • metres per second ↔ ft/s

Time

Quickly translate durations:

  • seconds, minutes, hours, days, weeks

Great for timelapses, workouts, or scheduling automations.

Pressure

Built for cycling, HVAC, labs, and weather:

  • PSI ↔ bar, kPa ↔ MPa, atmosphere (atm)
  • Torr (mmHg), inch of mercury (inHg), millimetre/inch of water (mmH₂O/inH₂O)

No more guesswork inflating tyres or reading technical datasheets.

Energy & Power

From appliances to heating systems:

  • joules (J) ↔ watt-hours (Wh) ↔ kilowatt-hours (kWh)
  • calories/kilocalories, BTU ↔ kWh, foot-pounds (ft⋅lb)
  • Power: watts (W) ↔ kilowatts (kW) ↔ horsepower (hp/PS), BTU/h, ton of refrigeration

Great for comparing tariffs, sizing heat pumps, or benchmarking devices.

Force, Frequency, Angle

Engineers and students get accurate conversions for:

  • newtons (N) ↔ pounds-force (lbf), kilonewtons (kN), dyne
  • hertz (Hz, kHz, MHz, GHz) and rpm
  • degrees ↔ radians, grads, arcminutes/arcseconds

Data Storage

Tech-friendly and precise:

  • bytes (B), kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB)
  • kibibytes (KiB), mebibytes (MiB), gibibytes (GiB) for binary units

Know the difference between KB (1000) and KiB (1024) at a glance.

Fuel Economy

Perfect for car research and trip planning:

  • mpg (UK) ↔ L/100 km, mpg (US) ↔ L/100 km
  • km/L - Compare real-world fuel use between UK, US, and metric ratings quickly.

Why Unit Pronto Converter Beats the Rest

1) Lightning-fast and intuitive. Type a value, choose “From” and “To”, and you’re done. The swap units button flips directions instantly, making back-and-forth checks effortless.

2) Optimised for high-value searches. It’s crafted around user intent for popular tasks like Miles to Kilometres converter, Pounds to Kilograms converter, Inches to Centimetres, Fahrenheit to Celsius, Litres to Gallons, PSI to Bar, Watts to Horsepower, and BTU to kWh—the conversions people actually search for every day.

3) Precision you control. Choose Auto for smart formatting or fix decimal places to 0, 2, 4, or 6. That’s invaluable when you’re pasting results into reports, CAD notes, or quotes.

4) World-ready units. It supports metric, US customary, and UK/Imperial measures side-by-side. You can compare US gallons with Imperial gallons correctly, and the tool includes niche units like Torr, inHg, ozt, and nautical miles for specialist jobs.

5) Copy and share cleanly. One click copies the result so you can drop it into emails, spreadsheets, or chats. No fluff—just the number you need.

6) Accuracy you can trust. The converter uses industry-standard constants (e.g., 1 mile = 1.609344 km, 1 in = 25.4 mm, 1 atm = 101,325 Pa, 1 kWh = 3.6 MJ). That means consistent outcomes across science, engineering, and everyday tasks.

7) Mobile-first design. Large controls, clear labels, and accessible colour contrast make it easy to use on phones and tablets when you’re on site or on the move.

How to Use the Unit Converter (Step-by-Step)

  1. Pick a category (e.g., Energy, Pressure, Length).
  2. Enter the value you want to convert. Scientific notation (like 1e-3) is supported.
  3. Select the From unit and To unit from the dropdowns.
  4. The result appears instantly. Tap the Swap button to reverse the direction.
  5. Use Precision to format the output exactly how you need it.
  6. Hit Copy result to paste into your document or message.

Real-World Examples

Travel & fitness: Plan UK–EU trips with a quick miles to kilometres check; convert mph to km/h on imported dashboards.

DIY & interiors: Order the right parts by converting inches to centimetres or square feet to square metres.

Cooking & hospitality: Translate American recipes with cups to millilitres and Fahrenheit to Celsius.

Engineering & trades: Set pressures with PSI to bar; size systems with BTU to kWh and Watts to Horsepower; interpret datasheets in kPa, MPa, atm, or Torr.

Education & research: Switch cleanly between joules, calories, eV, or newtons and pounds-force for reports and lab notes.

Motoring: Compare car reviews worldwide with mpg (UK/US) to L/100 km.

FAQs

Is a mile 1.6 km?
A mile equals 1.609344 kilometres. Our Miles to Kilometres converter uses the exact constant for precise results.

How many centimetres are in an inch?
Exactly 2.54 cm. Use the Inches to Centimetres converter for fast conversions in clothing, furniture, and screens.

What is 1 PSI in bar?
1 PSI ≈ 0.0689476 bar. The PSI to Bar converter gives accurate tyre and system pressures instantly.

How do I convert BTU to kWh?
1 kWh = 3412.1416 BTU (IT), and 1 BTU ≈ 0.000293071 kWh. Use the BTU to kWh converter to compare heating and cooling loads or tariffs.

What’s the difference between US and UK gallons?
A US gallon is 3.785 L, while an Imperial (UK) gallon is 4.546 L. Our Litres to Gallons converter handles both.