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Unit Converter

Length, weight, and volume in one place.

Result
0.001000 km
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Quick summary

Convert between metric and imperial units of length, weight, and volume.

How to calculate unit converter manually

  1. Each unit has a conversion factor to a base unit (m, kg, L).
  2. result = value · factor(from) / factor(to).

Convert between metric and imperial units of length, weight, and volume.

How it works

Each unit has a conversion factor to a base unit (m, kg, L). result = value · factor(from) / factor(to).

Example

1 mile = 1609.34 meters.

Expert guide

Unit conversion done right: metric, imperial, and US customary

Converting between units of length, weight, and volume sounds trivial — until a missed factor of 1.609 or 28.35 turns a recipe, a workout plan, or a freight invoice into a costly mistake. A reliable converter clears the friction in seconds.

Metric vs. US customary vs. imperial

Most of the world uses the SI metric system: meters, kilograms, liters. The United States is the largest holdout, using a mix of the older US customary units (inches, pounds, fluid ounces) for everyday life and SI for science and medicine. The UK adds a third wrinkle: imperial units share names with US customary ones but differ — an imperial gallon is 4.546 liters while a US gallon is 3.785 liters. Always confirm which gallon, ounce, or ton you're working with before converting, especially for shipping, recipes, and fuel economy.

Common conversion landmarks worth memorizing

A short list of high-frequency conversions removes friction from daily work. 1 inch = 2.54 cm exactly. 1 foot = 30.48 cm. 1 mile = 1.609 km. 1 pound = 0.4536 kg (so a 165 lb adult is about 75 kg). 1 US fluid ounce = 29.57 mL — making a 16 oz US pint roughly 473 mL. For cooking, 1 US cup = 240 mL, 1 US tablespoon = 14.8 mL. For temperature, °F to °C is (F − 32) × 5/9. Once these landmarks live in your head, you can sanity-check any converter result.

Why precision matters for engineering and trade

In engineering, medicine, and international shipping, even a 0.1% conversion drift can compound into a real problem — the famous Mars Climate Orbiter loss in 1999 came from a pound-seconds vs. newton-seconds mismatch. This converter uses the official 1959 international yard-and-pound agreement (1 yard = 0.9144 m exactly), so every length conversion is internally consistent and reversible. For high-stakes work, always carry six significant digits and round only at the very end.

Frequently asked questions

Is a US gallon the same as a UK gallon?

No. A US gallon is 3.785 liters, while a UK (imperial) gallon is 4.546 liters — about 20% larger. The same gap exists for fluid ounces, pints, and quarts. When converting recipe volumes, fuel-economy figures, or shipping quotes between US and UK sources, always check which system the original number came from.

How do I convert kilograms to pounds in my head?

Multiply kg by 2.2 for a quick estimate (close enough for groceries and luggage), or by 2.2046 for a more precise figure. So 70 kg ≈ 154 lb, and 100 kg ≈ 220 lb. Going the other way, divide pounds by 2.2 — a 200 lb person is about 91 kg.

Why does my converter sometimes show 0.999999 instead of 1?

Floating-point arithmetic in JavaScript (and most programming languages) cannot represent every decimal exactly. For practical purposes, treat results as accurate to about 12 significant digits and round to the precision you need. This calculator displays six decimals by default, which exceeds the precision required for any everyday or engineering use.

What's the most accurate way to measure for cooking?

Weight (grams) beats volume (cups, tablespoons) for repeatability — flour packed loosely vs. tightly into a measuring cup can vary by 30%. Professional bakers and serious home cooks weigh ingredients on a 0.1 g kitchen scale and ignore volume entirely. For liquids, both work well; just be consistent.

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