# Ounces to Kilograms (oz to kg)

> Convert ounces to kilograms: 1 oz = 0.0283495 kg. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `oz-to-kg` · Quantity: Mass (`mass`, base unit kg) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/oz-to-kg · This document: https://tttkmbb.com/conversion/oz-to-kg.md · JSON: https://tttkmbb.com/conversion/oz-to-kg.json (add `?value=` for a result)

## Formula

- `1 oz = 0.0283495 kg`
- `kilograms = ounces × 0.02834952313`
- Reverse: `ounces = kilograms × 35.27396195`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 oz = 0.141748 kg
- 12.5 oz = 0.354369 kg
- 100 oz = 2.83495 kg

## Conversion table

| Ounces (oz) | Kilograms (kg) |
| --- | --- |
| 1 | 0.0283495 |
| 2 | 0.056699 |
| 3 | 0.0850486 |
| 4 | 0.113398 |
| 5 | 0.141748 |
| 6 | 0.170097 |
| 7 | 0.198447 |
| 8 | 0.226796 |
| 9 | 0.255146 |
| 10 | 0.283495 |
| 15 | 0.425243 |
| 20 | 0.56699 |
| 25 | 0.708738 |
| 30 | 0.850486 |
| 40 | 1.13398 |
| 50 | 1.41748 |
| 75 | 2.12621 |
| 100 | 2.83495 |
| 200 | 5.6699 |
| 250 | 7.08738 |
| 500 | 14.1748 |
| 1000 | 28.3495 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=oz&to_unit=kg` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"oz","to_unit":"kg"}`
- All mass units: https://tttkmbb.com/api/v1/units?quantity=mass · full converter: [Mass / Weight Converter](https://tttkmbb.com/conversion/mass.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many kilograms are in one ounce?**

1 oz = 0.0283495 kg. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert ounces to kilograms?**

Multiply the value in ounces by 0.02834952313: kilograms = ounces × 0.02834952313. For example, 5 oz = 0.141748 kg.

**How do I convert kilograms back to ounces?**

Multiply by the inverse factor 35.27396195 (ounces = kilograms × 35.27396195), or use the kilograms-to-ounces page.

## Related conversions

- [Kilograms to ounces](https://tttkmbb.com/conversion/kg-to-oz.md) (reverse)
- [Kilograms to Pounds](https://tttkmbb.com/conversion/kg-to-lbs.md)
- [Pounds to Kilograms](https://tttkmbb.com/conversion/lbs-to-kg.md)
- [Grams to Ounces](https://tttkmbb.com/conversion/grams-to-oz.md)
- [Ounces to Grams](https://tttkmbb.com/conversion/oz-to-grams.md)
- [Kilograms to Stone](https://tttkmbb.com/conversion/kg-to-stone.md)
- [Stone to Kilograms](https://tttkmbb.com/conversion/stone-to-kg.md)
- [Pounds to Ounces](https://tttkmbb.com/conversion/lbs-to-oz.md)
- [Ounces to Pounds](https://tttkmbb.com/conversion/oz-to-lbs.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)