Calculator
What the Carat Converter does
Carat Converter: 1 ct = 0.2 g, so multiply a carat value by 0.2 to get gram, or divide to go back. Example: 1 ct = 0.2 g.
Point it at Value, From and To and it returns Result, How it was calculated and Reverse conversion. Each change is reflected immediately, which suits quick what-if comparisons.
Two industries often use the same word for slightly different quantities. The Carat Converter exists to take that particular chore off your hands.
No sign-up, no data collection, no processing queue, just code running locally.
The sections that follow cover the fields, the method, and one full example computed from the defaults.
What do the Carat Converter fields mean?
The Carat Converter uses 3 inputs. Starting values are already in place, which saves the usual blank-form hesitation about what a field wants.
| Field | What to enter | Default |
|---|---|---|
| Value | required | 1 |
| From | choose from Microgram (µg), Milligram (mg), Gram (g), Kilogram (kg), Tonne (metric ton) (t) or Grain (gr) | Carat (ct) |
| To | choose from Microgram (µg), Milligram (mg), Gram (g), Kilogram (kg), Tonne (metric ton) (t) or Grain (gr) | Gram (g) |
How does the Carat Converter work?
Both units are converted through mass's base unit (kg), so any of the 13 units in the dropdowns can be paired in either direction without loss of accuracy.
Definitions are taken from the SI system where one exists, and from CODATA or the IAU where a unit is established by measurement. No factor is rounded before the calculation.
Worked example
These are the values the Carat Converter loads by default, and the result it produces from them. The figures are the tool’s live defaults and its live output, so you can reproduce them exactly.
| Value | 1 |
|---|---|
| From | Carat (ct) |
| To | Gram (g) |
| Result | 0.2 g |
|---|---|
| How it was calculated | 1 ct = 0.2 g, so 1 × 0.2 = 0.2 g |
| Reverse conversion | 5 ct (if you meant 1 g) |
The carat
The metric carat equals exactly 200 milligrams (0.2 g), standardised internationally in 1907: before that, "carat" varied somewhat by country, since it was originally based on the fairly (but not perfectly) consistent weight of dried carob seeds.
Worth knowing
- It is used almost exclusively for gemstones, especially diamonds. A "1 carat" diamond weighs exactly 0.2 g regardless of its physical size, since diamond density varies only slightly and carat measures mass, not volume.
- Don’t confuse "carat" (a unit of mass, spelled with a c) with "karat" (a measure of gold purity, spelled with a k, where 24 karat means pure gold). The words sound identical and are frequently mixed up despite describing completely different things.
- Modern research suggests carob seeds actually vary in weight more than the old legend implies, so the historical basis for the unit is somewhat more myth than precise measurement: a reminder that many pre-metric units were "standardised" only loosely until an exact metric definition was assigned to them.
Definitions: BIPM SI Brochure · NIST reference on units
How to use it
- Enter Value.
- Pick a value for From: the options are Microgram (µg), Milligram (mg), Gram (g), Kilogram (kg), Tonne (metric ton) (t) or Grain (gr).
- Pick a value for To: the options are Microgram (µg), Milligram (mg), Gram (g), Kilogram (kg), Tonne (metric ton) (t) or Grain (gr).
- The result appears as you type. There is no button to press.
- You get Result, How it was calculated and Reverse conversion back.
- The link encodes your inputs, so saving it is enough to reproduce the result later.
What this tool does not do
- Repeated conversions compound rounding, so convert once from the original value where you can.
- Conversion factors use SI definitions; some industries use their own rounded factors.
- The output is a number, not a judgement. Deciding what it means is still your job.
- Results are only as good as the inputs. Check your units before reading anything into the output.
Frequently asked questions
Only Value, From and To. Defaults are loaded for all of them, which makes it easy to isolate the effect of a single variable.
With the values loaded when the page opens, result comes out as 0.2 g. That number tracks the inputs, so a small edit shows its sensitivity immediately.
Nothing leaves your machine. The only network traffic is loading the page itself.
Free, and there is no upsell. The whole tool is the free version.
It matches what you would get working it out by hand, with fewer opportunities to slip.