# How do I convert lbs and oz to kg?

Converts pounds and ounces to kilograms: kg = (lb × 16 + oz) × 0.028349523125.

- Page: https://www.acalculator.org/convert/lbs-and-oz-to-kg
- JSON spec: https://www.acalculator.org/convert/lbs-and-oz-to-kg.json
- Version: 3a5a94ec4907

## Default answer

Example with the default inputs (Pounds (lb) 7, Ounces (oz) 8): 7 lb 8 oz = 3.401943 kg.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Pounds (lb) | The whole pounds. |
| oz | Ounces (oz) | The ounces on top of the pounds. |
| result | Kilograms (kg) | The weight in kilograms. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Pounds (lb) | The whole pounds. |
| oz | Ounces (oz) | The ounces on top of the pounds. |
| result | Kilograms (kg) | The weight in kilograms. |

## Method

kg = (lb × 16 + oz) × 0.028349523125

## Assumptions

- 1 lb = 16 oz = 0.45359237 kg exactly, so 1 oz = 0.028349523125 kg (NIST SP 811). Ounces may be 16 or more.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up.

## Worked examples

1. value = 7, oz = 8 gives result = 3.401943. Source: NIST SP 811 (2008), Appendix B.8: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb.
2. value = 1, oz = 0 gives result = 0.453592. Source: NIST SP 811 (2008), Appendix B.8: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb.
3. value = 0, oz = 16 gives result = 0.453592. Source: NIST SP 811 (2008), Appendix B.8: 1 lb = 0.45359237 kg, 1 oz = 1/16 lb.

## FAQ

### How do I convert lbs and oz to kg?

Turn the weight into ounces, then multiply by 0.028349523125: kg = (lb × 16 + oz) × 0.028349523125. A pound is exactly 0.45359237 kg and an ounce is 1/16 of it.

### What is 7 lb 8 oz in kg?

(7 × 16 + 8) × 0.028349523125 = 120 × 0.028349523125 = 3.401943 kg.

### What is 8 lb 3 oz in kg?

131 oz × 0.028349523125 = 3.713788 kg.

### Can I type ounces only?

Yes. Set the pounds to 0. 16 oz is 0.453592 kg, the same as 1 lb 0 oz. Ounces of 16 or more are fine.

### How do I convert kg back to pounds and ounces?

Use the kg to lbs and oz converter, which gives whole pounds and the ounces left over. On this page, type the kilograms and the pounds, and the ounces show.

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Table 5 (SI prefixes) and Appendix B.8 (factors for units listed alphabetically), retrieved 2026-10-05. https://www.nist.gov/pml/special-publication-811