---
title: "Carats to Stone — ct to st converter"
description: "1 carat = 0.00003149 stone. Convert carats to stone with a full conversion table, the exact formula, and a calculator for any value."
url: https://atoneplace.net/convert/carats-to-stone/
site: "At One Place"
---

# Carats to stone

**1 carat in stone: 1 ct = 0.00003149 st**

st = ct × 0.000031494609

To convert carats to stone, multiply by 0.000031494609. The table below gives the values people look up most often, and the converter works for any number.

## Carats to stone table

*Common carat values converted to stone.*

| Carats | Stone |
| --- | --- |
| 1 ct | 0.00003149 |
| 2 ct | 0.00006299 |
| 3 ct | 0.00009448 |
| 4 ct | 0.000126 |
| 5 ct | 0.0001575 |
| 10 ct | 0.0003149 |
| 15 ct | 0.0004724 |
| 20 ct | 0.0006299 |
| 25 ct | 0.0007874 |
| 30 ct | 0.0009448 |
| 40 ct | 0.0012598 |
| 50 ct | 0.0015747 |
| 75 ct | 0.0023621 |
| 100 ct | 0.0031495 |
| 250 ct | 0.0078737 |
| 500 ct | 0.015747 |
| 1,000 ct | 0.031495 |

## How the conversion works

The relationship is st = ct × 0.000031494609. Both units measure mass, so the conversion is a fixed factor that never changes. The figure is exact rather than approximate: since the international yard and pound agreement of 1959, an inch is defined as exactly 25.4 millimetres and a pound as exactly 0.45359237 kilograms, and every other imperial and US customary unit here is derived from those two.

## Common questions

### How many stone are in one carat?

One carat equals 0.00003149 stone. st = ct × 0.000031494609.

### How do you convert carats to stone?

Use st = ct × 0.000031494609. So 10 ct is 0.0003149 st.

### How many carats are in one stone?

One stone equals 31,751.466 carats, which is the reverse of the conversion above.

## Related pages

- [Stone to Carats](https://atoneplace.net/convert/stone-to-carats/)
- [Carats to Kilograms](https://atoneplace.net/convert/carats-to-kg/)
- [Carats to Grams](https://atoneplace.net/convert/carats-to-grams/)
- [Carats to Milligrams](https://atoneplace.net/convert/carats-to-mg/)
- [Carats to Tonnes](https://atoneplace.net/convert/carats-to-tonnes/)
- [Carats to Pounds](https://atoneplace.net/convert/carats-to-lbs/)
- [Carats to Ounces](https://atoneplace.net/convert/carats-to-oz/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)