Weight Converter.

Convert weight between kg, g, mg, lb, oz, stone, and metric tonnes. Type any value and see all units at once.

Enter a weight in any unit and instantly see the equivalent in kilograms, grams, milligrams, pounds, ounces, stone, and metric tonnes. All conversions use exact internationally-defined ratios and results are shown to 6 significant figures.

How to use

Enter a value in the number box and select the source unit from the dropdown. All other units update instantly in the cards below.

Weight causes confusion because the context keeps changing

The same person might deal with kilograms on a luggage scale, stone and pounds in a family conversation, grams in a recipe, and tonnes in a supplier quote. None of those are exotic units; they just belong to different contexts. The friction comes from switching between them quickly and accurately.

This tool converts one entered value into kilograms, grams, milligrams, pounds, ounces, stone, and metric tonnes in one view. That is useful when the question is not just “what is this in another unit?” but “which of these numbers is the one I actually need right now?”

The situations that matter most

Body weight

The UK still mixes kilograms with stone and pounds. If your scale says 74 kg and someone asks for your weight in stone, the conversion is about 11 st 9 lb. That is much easier to trust when you read it directly than when you approximate via pounds in your head.

Recipes and baking

Weight conversions matter more in baking than most people think. Eight ounces of flour is about 227 g. If you round too aggressively or swap ounces and fluid ounces, the result is no longer the same recipe.

Luggage and shipping

Airline limits are one of the few places where a small conversion error turns straight into money. A 50 lb checked-bag limit is about 22.7 kg. If your scale reads 23 kg, you are not “close enough”; you are already over.

Supplier and freight pricing

Bulk goods may be quoted per pound, per kilogram, or per tonne. Until the units match, the prices do not.

The units people trip over

Stone is not a decimal unit

Stone is usually written as stone plus pounds, such as 11 st 9 lb. Do not enter “11.9 stone” unless you really mean eleven point nine stone. If you have a mixed value, convert it to pounds first and then use the tool.

Ounces are not always fluid ounces

Weight ounces and fluid ounces are different things. If you are looking at ingredients, check whether the recipe is talking about mass or liquid volume before converting.

Tonne is not the same as ton

A metric tonne is 1,000 kg. A US short ton is 2,000 lb. Those are not interchangeable labels.

Practical examples

Checking a suitcase before the airport

If your case weighs 21.8 kg and the airline allows 50 lb, you are under the limit. If it weighs 23.1 kg, you are not. This is exactly the sort of question where a precise conversion saves guesswork.

Comparing supermarket packs

One product may be sold in grams and another in ounces. Converting both to one unit before judging the price per unit is the only fair comparison.

Converting a specification

If a technical note says a component weighs 2.5 lb and your documentation uses grams, converting once and recording the metric value avoids repeated manual errors later.

What this tool does not do

This tool converts mass units only. It does not price shipping, estimate postage bands, convert between mass and volume, or handle specialist units like troy ounces for precious metals.

Good habits

Examples

1 kg 1,000 g · 2.20462 lb · 35.274 oz · 0.157473 st
1 lb 453.592 g · 0.453592 kg · 16 oz · 0.0714286 st
70 kg (avg adult) 70,000 g · 154.324 lb · 11.023 st

FAQ

What is a stone?

A stone is a unit of weight used in the UK and Ireland, equal to 14 pounds or approximately 6.35 kg. It is commonly used for body weight.

Is a tonne the same as a ton?

No. A metric tonne is 1,000 kg (2,204.6 lb). A US short ton is 2,000 lb (907.2 kg). A UK long ton is 2,240 lb (1,016 kg). This tool uses the metric tonne.

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Privacy and data handling

This tool runs entirely in your browser. Nothing you type or paste is sent to any server — all processing happens locally on your device.