Unit Converter: Instantly Convert Length, Weight, and Volume
Unit conversion is a daily task for engineers, students, cooks, travellers, and anyone working across metric and imperial systems. Our Unit Converter handles all three major physical quantity categories — length, weight, and volume — with a clean, single-page interface that calculates results as you type.
Choose a category (Length, Weight, or Volume), enter your value, select your source and target units, and the result appears instantly. A swap button reverses the direction with one click. The Conversion Details panel shows the full equation so you can verify the calculation at a glance.
Pre-loaded quick examples for each category let you see common conversions immediately — metric cm to m, imperial lb to kg, or volume gal to L.
Each unit is defined by its factor relative to a common base unit (metres for length, kilograms for weight, litres for volume). To convert, multiply the input by the source factor to reach the base, then divide by the target factor.
Metric vs Imperial: Quick Reference
Length: The metric system uses millimetres, centimetres, metres, and kilometres. The imperial system uses inches, feet, yards, and miles. 1 metre = 3.28084 feet. 1 kilometre = 0.621371 miles.
Weight: Metric uses milligrams, grams, kilograms, and metric tonnes. Imperial uses ounces and pounds. 1 kilogram = 2.20462 pounds. 1 pound = 16 ounces.
Volume: Metric uses millilitres, litres, and cubic metres. US customary uses teaspoons, tablespoons, fluid ounces, cups, pints, quarts, and gallons. 1 litre = 0.264172 US gallons. 1 US cup = 236.588 ml.
Common Conversion Factors
Length: 1 inch = 2.54 cm · 1 foot = 30.48 cm · 1 mile = 1.60934 km · 1 yard = 0.9144 m
Weight: 1 pound = 453.592 g · 1 ounce = 28.3495 g · 1 metric tonne = 1,000 kg
Volume: 1 US gallon = 3.78541 L · 1 US cup = 236.588 ml · 1 fl oz = 29.5735 ml · 1 pint = 473.176 ml
Practical Examples
Converting a Recipe from US Cups to Millilitres
US recipes use cups while metric recipes use millilitres. This is a common conversion in cooking.
- 1.Category: Volume
- 2.From: Cups · To: Milliliters
- 3.Input: 2 cups
- 4.Result: 473.176 ml
- 5.Use case: Scaling baking recipes between US and metric measurements
Converting Body Weight from Pounds to Kilograms
Medical and fitness contexts often require switching between lb and kg.
- 1.Category: Weight
- 2.From: Pounds · To: Kilograms
- 3.Input: 154 lb
- 4.Result: 69.8534 kg
- 5.Use case: BMI calculations, medical records, gym equipment calibrated in kg
Frequently Asked Questions
What unit categories does this converter support?
The converter supports three categories: Length (mm, cm, m, km, in, ft, yd, mi), Weight (mg, g, kg, metric tonnes, oz, lb), and Volume (ml, L, cubic meters, tsp, tbsp, fl oz, cups, pints, quarts, gallons).
How accurate are the conversions?
All conversions use internationally recognised exact or high-precision factors. For example, 1 inch = 0.0254 m exactly (SI definition), 1 pound = 0.45359237 kg exactly. Results are displayed to up to 8 significant figures.
Can I swap the From and To units?
Yes. The swap button (⇄) between the two dropdowns instantly reverses the conversion direction, recalculating the result with the same input value.
What is the difference between metric tonnes and kilograms?
One metric tonne equals 1,000 kilograms. Metric tonnes are used for large mass measurements such as shipping cargo or vehicle weights. Kilograms are the SI base unit for everyday mass.
How do I convert US cups to millilitres?
Select Volume, set From to Cups and To to Milliliters, then enter your value. One US cup equals 236.588 ml. The converter uses the US customary cup definition.
What is the difference between fluid ounces and ounces (weight)?
Fluid ounces measure volume (roughly 29.57 ml for US fluid ounces) while ounces in the Weight category measure mass (28.35 g). They are different physical quantities — choose the correct category for your use case.
Does the converter work offline?
Yes. All calculations run entirely in your browser with no server requests, so the tool works without an internet connection once the page has loaded.
How do I convert miles to kilometres?
Select Length, set From to Miles and To to Kilometers, then enter your distance. One mile equals 1.609344 km exactly.