LBS to KG Converter
Turn a US customary weight — a clinic scale in pounds, a shipping quote, or a baby’s birth weight — into kilograms for a metric form or passport.
Updated
How to use
- Enter pounds. If you have stones and pounds, convert stones to pounds first (× 14) and add the leftover pounds.
- Read kilograms. 150 lb is 68.0389 kg.
- For a baby weight such as 7 lb 8 oz, convert ounces to a decimal pound (8/16 = 0.5) so you enter 7.5.
- Use the kilogram → pound page when the original number was metric.
How it works
US medical forms, shipping APIs and older home scales often store pounds. Metric clinics, EU customs forms and most lab results want kilograms. This page multiplies pounds by 0.45359237, the defined mass of one international avoirdupois pound. The reverse of “divide by 0.45359237” is this multiply, so 150 lb comes back as 68.0389 kg rather than a rounded 68.
Birth weight is a typical US customary leftover. 7 lb 8 oz is 7.5 lb, which is 3.4019 kg. 8 lb 4 oz is 8.25 lb, or 3.7421 kg. Pediatric charts that switched to kilograms still need that first conversion from the hospital bracelet.
Shipping is the other daily use. A 40 lb parcel is 18.1437 kg. A 70 lb freight piece is 31.7515 kg. Carriers that bill by kilogram will re-weigh; this tool only translates the number you already have, including any packing weight you typed in.
Barbell math in US gyms starts from 45 lb plates. Two plates a side on a 45 lb bar is 225 lb, which is 102.0583 kg. If the gym also has 20 kg plates, do not treat them as 45 lb twins — convert each stamp.
Troy pounds (12 troy ounces) are for precious metals and are not used here. A “pound of feathers vs pound of gold” joke mixes avoirdupois and troy; this converter is avoirdupois only.
Formula
kilograms = pounds × 0.45359237
Worked examples
One pound
1 lb → 0.4536 kg
A common US clinic reading
150 lb → 68.0389 kg
Two 45 lb plates plus a 45 lb bar
225 lb → 102.0583 kg
US scale pounds in kilograms
| lb | kg |
|---|---|
| 1 | 0.4536 |
| 150 | 68.0389 |
| 180 | 81.6466 |
| 200 | 90.7185 |
| 220 | 99.7903 |
Useful notes
- Avoirdupois pounds only. Troy pounds are a different unit.
- Stone: multiply stones by 14 to get pounds, then convert.
- Ounces on a baby scale are 1/16 of a pound. Add them as a decimal first.
FAQ
- How many kilograms is one pound?
Exactly 0.45359237 kilograms, by international definition.
- How many kilograms is 150 pounds?
150 × 0.45359237 = 68.0388555 kg, about 68.04 kg to two decimals.
- Why not just multiply by 0.45?
0.45 is a rough shortcut (off by about 0.8%). This tool uses the exact defined constant so repeated conversions invert cleanly.
- How do I convert 11 stone 6 pounds?
11 × 14 + 6 = 160 lb, then 160 × 0.45359237 ≈ 72.5748 kg.
- Is a pound of gold the same?
Not if someone meant troy weight. This page is the everyday avoirdupois pound used on scales and shipping labels.
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