Convert between ounces, pounds, pints, gallons and more — US customary and UK imperial units, with metric equivalents.
Weight conversion
All units (click any value to copy)
Volume conversion
All units (click any value to copy)
Quick reference table
| Conversion | Value |
|---|---|
| 1 pound (lb) | 16 oz = 453.592 g |
| 1 ounce (oz) | 28.3495 g |
| 1 stone | 14 lb = 6.35029 kg |
| 1 US short ton | 2000 lb = 907.185 kg |
| 1 UK long ton | 2240 lb = 1016.047 kg |
| 1 US fl oz | 29.5735 ml |
| 1 UK fl oz | 28.4131 ml |
| 1 US cup | 8 US fl oz = 236.588 ml |
| 1 US pint | 16 US fl oz = 473.176 ml |
| 1 UK pint | 20 UK fl oz = 568.261 ml |
| 1 US quart | 2 US pt = 946.353 ml |
| 1 US gallon | 4 US qt = 3.78541 L |
| 1 UK gallon | 4 UK qt = 4.54609 L |
| 1 US tbsp | 14.7868 ml |
| 1 US tsp | 4.92892 ml |
| 1 US oil barrel | 42 US gal = 158.987 L |
Frequently asked questions
What is the difference between US and UK fluid ounces?
A US fluid ounce is 29.5735 ml, while a UK (imperial) fluid ounce is 28.4131 ml. The UK ounce is about 4% smaller. But both systems use "fl oz" as the label, which is why volumes like pints and gallons also differ between the two systems.
Why is a US gallon different from a UK gallon?
The US gallon (3.78541 L) is based on a historical wine gallon of 231 cubic inches. The UK imperial gallon (4.54609 L) was redefined in 1824 as the volume of 10 pounds of water. The UK gallon is about 20% larger than the US gallon, which means UK pints and quarts are also larger than their US equivalents.
Are dry ounces and fluid ounces the same?
No. A fluid ounce measures volume (about 29.57 ml in the US). A dry or avoirdupois ounce measures weight (28.3495 g). They are close but not equal, and the match is only coincidental for water. For other substances like flour, sugar, or oil, fluid ounces and weight ounces are different.
How much does 1 gallon of water weigh?
1 US gallon of water weighs about 8.345 lb (3.785 kg) at room temperature. 1 UK gallon of water weighs about 10.022 lb (4.546 kg). The UK gallon was historically defined so that 1 gallon equals 10 pounds of water, which is where the modern value comes from.
How do I convert cups to tablespoons or teaspoons?
1 US cup = 16 US tablespoons = 48 US teaspoons. 1 US tablespoon = 3 US teaspoons = 14.79 ml. 1 US teaspoon = 4.93 ml. These ratios are consistent across US recipes. Metric cups (250 ml) used in Australia and Canada are slightly larger.
What is avoirdupois weight, and why is it called that?
Avoirdupois is the standard English system for everyday weights: 1 lb = 16 oz = 7000 grains. The name comes from Old French "aveir de peis" (goods of weight), used for bulk commodities traded by weight. Troy weight (used for precious metals) is different: 1 troy oz = 31.1035 g, and 1 troy pound = 12 troy oz. This calculator uses avoirdupois throughout.
This converter handles both weight and volume in traditional US customary and UK imperial units, alongside metric equivalents for reference. The weight tab covers ounces, pounds, stones, US short tons, UK long tons, drams and grains, plus grams, kilograms and tonnes. The volume tab covers teaspoons, tablespoons, fluid ounces, cups, pints, quarts, gallons, oil barrels, millilitres and litres. A US/UK toggle switches volume units between the two systems, since a US fluid ounce is 29.5735 ml while a UK fluid ounce is 28.4131 ml. Enter a value, choose a unit, and all other units update at once. For example, 1 US gallon equals 3.78541 litres, and 1 UK gallon equals 4.54609 litres. Click any result to copy it. Presets cover common recipe amounts like 1 cup, 1 tbsp, 1 lb. Includes a quick reference table and answers to common questions about US vs UK units, fluid vs weight ounces, and avoirdupois weight.