Carat to Pennyweight Converter

Mass Converter

26 units available

Decimals:

From

To

0.128603

1 ct = 0.128603 dwt

Formula:

dwt = ct × 0.1286029863

With your value: 1 ct = 0.12860299 dwt

How big is that?

Everyday references on a logarithmic scale, all expressed in carat so you can sanity-check the result.

Your value1.00 ct

Paperclip (5.0× your value)5.00 ct

AA battery (1.2e+2× your value)120 ct

Can of soda (2.0e+3× your value)1.95e+3 ct

Bag of sugar (5.0e+3× your value)5.00e+3 ct

House cat (2.3e+4× your value)2.25e+4 ct

Other Carat to Pennyweight conversions

2 ct to dwt 3 ct to dwt 4 ct to dwt 5 ct to dwt 6 ct to dwt 7 ct to dwt 8 ct to dwt

Carat to Pennyweight Conversion Table

Carat (ct)	Pennyweight (dwt)
0.5	0.064301
1	0.128603
2	0.257206
5	0.643015
10	1.28603
15	1.929045
20	2.57206
25	3.215075
50	6.430149
100	12.860299
250	32.150747
500	64.301493
1000	128.602986

Pennyweight to Carat Conversion Table

Pennyweight (dwt)	Carat (ct)
0.5	3.887935
1	7.775869
2	15.551738
5	38.879346
10	77.758692
15	116.638038
20	155.517384
25	194.39673
50	388.79346
100	777.58692
250	1,943.9673
500	3,887.9346
1000	7,775.8692

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Carat (ct)

Mass

Conventional value

The metric carat is exactly 200 mg, agreed internationally in 1907.

Source: NIST Handbook 44, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

Pennyweight (dwt)

Mass

Exact conversion

Traceable to the kilogram, defined by fixing the Planck constant at 6.626 070 15 × 10⁻³⁴ J·s. Avoirdupois masses derive from the 1959 international pound (0.453 592 37 kg exactly).

Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)

Bureau International des Poids et Mesures · Reviewed 2026-07-01

How to Convert Carat to Pennyweight

To convert from Carat (ct) to Pennyweight (dwt), multiply the value by 0.1286029863.

Formula: dwt = ct × 0.1286029863

Reverse: ct = dwt × 7.7758692

Step-by-Step Example

Start with your value in Carat. For example: 5 ct
Multiply by the conversion factor: 5 x 0.1286029863
The result is: 0.643015 dwt

About Carat

The carat equals 200 milligrams and is the standard unit for measuring gemstone weight.

Fun Fact: The word "carat" comes from the carob seed, which was used as a balance weight in ancient gem trading.

Common uses: gemstones, diamonds, jewelry.

About Pennyweight

The pennyweight (dwt) equals 1/20 of a troy ounce, about 1.555 grams. Jewellers still price scrap gold by the pennyweight.

Common uses: jewellery trade, gold scrap, assaying.

Frequently Asked Questions

How many Pennyweight are in 1 Carat?

There are exactly 0.1286029863 Pennyweight in 1 Carat. This means the conversion factor from Carat to Pennyweight is 0.1286029863.

What is the formula to convert Carat to Pennyweight?

The formula to convert Carat to Pennyweight is: dwt = ct × 0.1286029863. For example, to convert 10 Carat to Pennyweight, you would multiply 10 by 0.1286029863.

What is a Carat?