Carat to Gram Converter

Carat To Gram Conversion Explained

Carats are the standard weight unit for diamonds and most gemstones. Grams, milligrams and ounces are more general-purpose units used in science, jewelry manufacturing and precious metals. This Carat to Gram Converter connects all of these units using exact formulas so you can move between them confidently.

Modern carats are strictly defined in terms of grams, which makes conversion straightforward and fully reversible. Once you understand the base definition, every other formula follows from it.

The Core Definition: Carats And Grams

The modern metric carat is defined as exactly one fifth of a gram. That is the starting point for all carat conversions:

This can be rewritten as a pair of direct formulas for converting back and forth between carats and grams.

Carats To Grams Formula

If you know the weight in carats and want grams, multiply by 0.2. Let C be the weight in carats and G be the weight in grams. Then:

Example: a 1.25 carat stone weighs:

The converter applies this formula whenever you enter a carat value as the starting unit.

Grams To Carats Formula

The inverse relationship comes from solving the previous formula for C. Since 1 carat = 0.2 grams, 1 gram equals 1 ÷ 0.2 = 5 carats. The gram to carat formula is:

Example: a small gem that weighs 0.08 grams has a carat weight:

In the calculator, any time you start from grams, it uses this formula internally to determine carats and then builds other conversions on top of that.

Carats To Milligrams

Milligrams are another metric weight unit frequently used for small items and lab work. The steps are:

• 1 gram = 1000 milligrams
• 1 carat = 0.2 grams

Combining these facts gives:

So the general formula is:

For example, a 0.35 carat stone weighs:

Milligrams To Carats

To go the other way, divide by 200:

If a gem is listed as 150 mg, its carat weight is:

Grams, Ounces And Troy Ounces

Outside of gemology, ounces are common in everyday and precious metal markets. There are two main ounce definitions:

• Standard ounce (avoirdupois): 1 oz = 28.349523125 grams
• Troy ounce: 1 ozt = 31.1034768 grams

The converter uses these exact constants so that carat weights can be linked accurately to both types of ounces.

Carats To Ounces Formula

To convert carats to ounces, first find grams, then divide by grams per ounce. Using C for carats and G for grams:

For standard ounces (oz):

For troy ounces (ozt):

The calculator follows this two-step approach internally for any conversion involving ounces or troy ounces.

From Any Unit To Every Other Unit

The multi-unit Carat to Gram Converter uses a simple internal structure:

• Convert the input unit to grams using the relevant formula.
• Convert those grams to carats, milligrams, ounces and troy ounces.
• Format each value to the number of decimal places you requested.

For example, if you start from ounces, it converts ounces to grams, then grams to carats, and then uses carats to generate milligrams and back to grams for display. This guarantees consistent and reversible results.

How To Use The Carat To Gram Converter Step-By-Step

• Enter the gemstone weight in the value field.
• Select the unit you are starting from: carats, grams, milligrams, ounces or troy ounces.
• Choose the number of decimal places for rounding.
• Click the convert button to generate all equivalent weights.
• Read off carats for gem listings, grams or milligrams for manufacturing and ounces or troy ounces for metals and trading.

Why Precise Unit Conversion Matters In Gemstones

Small differences in weight can translate into meaningful price gaps, especially with diamonds and high-value colored stones. A tenth of a carat can make a noticeable difference in value around key thresholds such as 0.50 ct, 1.00 ct or 2.00 ct. Using exact conversion factors helps you verify weights and cross-check information from different sources.

This Carat to Gram Converter is designed to be simple for quick checks while still grounded in accurate definitions. You can trust that each result flows from clear formulas rather than rough approximations.