Weight and shipping converters
Convert between kilograms, pounds, grams and ounces. Includes a luggage packing calculator for airline weight limits. Instant results for shopping, travel and shipping.
Last updated: May 2026
Core weight converters
Most weight conversions come up when buying imported goods, checking luggage limits or comparing fitness and nutrition figures across metric and imperial sources.
Shipping and travel
Before you travel or ship a package, knowing the exact weight against an allowance saves time and avoids surcharges.
When you need a weight converter
Weight is the most practical unit to get wrong. An airline states limits in kilograms, a fitness app in pounds, a US product listing in ounces. Converting before you act, whether packing a bag, ordering goods or reading a recipe, prevents the kind of small arithmetic error that causes a baggage fee or a failed batch.
The safe rule: check the unit on the limit or target before converting, not after.
Weight conversion factors
| Conversion | Multiply by | Example |
|---|---|---|
| kg to lb | 2.2046 | 20 kg = 44.1 lb |
| lb to kg | 0.4536 | 150 lb = 68 kg |
| g to oz | 0.03527 | 250 g = 8.82 oz |
| oz to g | 28.35 | 4 oz = 113.4 g |
| stone to kg | 6.350 | 12 st = 76.2 kg |
Weight in everyday contexts
Weight units matter differently depending on the task. Luggage limits use kilograms at most carriers or pounds at some US airlines. Food labelling uses grams and kilograms in the EU and ounces and pounds in the US. Body weight in the UK and Ireland is often expressed in stones (1 stone = 14 lb = 6.35 kg), which requires a two-step conversion when comparing to metric records.
| Context | Typical unit | Practical reference |
|---|---|---|
| Airline checked bag limit | 23 kg | 50.7 lb; upper limit before rejection is usually 32 kg = 70.5 lb |
| Letter or small parcel | 100 g to 2 kg | Royal Mail large letter maximum: 750 g |
| Body weight (adult average) | 60 to 100 kg | 132 to 220 lb; 9.5 to 15.7 stone in UK terms |
| Cooking portion (meat) | 150 to 300 g per serving | 5.3 to 10.6 oz; recipe weights are always in grams in EU editions |
| Parcel surcharge threshold | 30 kg | 66.1 lb; packages above this attract heavy-item fees at most carriers |
Troy weight is used for precious metals and differs from the avoirdupois system used for everyday goods. One troy ounce is 31.1 grams, about 10 percent heavier than an avoirdupois ounce (28.35 g). Gold and silver prices always quote troy ounces, so a price "per ounce" in a jewellery or investment context is not the same ounce as in a recipe.
Frequently Asked Questions
How many pounds are in a kilogram?
One kilogram is 2.205 pounds, and one pound is 0.454 kg. A quick mental estimate is to double the kilograms and add about 10 percent: 20 kg doubles to 40, plus 10 percent is 44 lb (the exact figure is 44.1).
What is the difference between weight and mass?
In everyday use "weight" usually means mass, and kilograms and pounds both measure mass here. True weight is a force measured in newtons, but for shopping, luggage and recipes the kg or lb figure is the one that matters.
What is a stone in kilograms and pounds?
One stone is 14 pounds, or about 6.35 kg. It is still used in the UK and Ireland for body weight, so 12 stone is roughly 76 kg or 168 lb.
How do airline baggage allowances work?
Most airlines state limits in kilograms, while some US carriers use pounds, so check your ticket. A common 23 kg checked limit is about 50 lb. The packing weight calculator lets you add items and compare against the limit.
Can I swap grams and ounces in a recipe?
Not one for one: one ounce is about 28.35 grams. For baking, weigh in grams for accuracy, because measuring by volume (cups) gives a different amount depending on the ingredient.
How do I convert stones to kilograms?
Multiply stones by 6.35 to get kilograms. 12 stone is 76.2 kg; 14 stone is 88.9 kg. To convert stones to pounds first, multiply by 14 then by 0.454 for kg. The kg to lbs converter handles any value in either direction.
What is a troy ounce and how does it differ from a regular ounce?
A troy ounce is 31.10 grams, used for gold, silver and precious metals. An avoirdupois ounce (used for food and everyday goods) is 28.35 grams, about 9 percent lighter. Gold and silver prices always quote troy ounces, so a price per ounce in a jewellery or investment context is not the same ounce as in a recipe.
How do postal weight limits work for international shipping?
Most postal services use stepped pricing based on weight bands. A typical large letter limit is 750 g; a standard parcel is up to 2 kg. Above 2 kg most services move to courier rates. Dimensional weight can also apply to large but light packages: multiply length by width by height in cm, divide by 5000, and the result in kg may be used instead of the actual weight if higher.