Gold Karat Conversion: 750, 900 and 995 with Table and Examples

By P-Soft Expert Team October 9, 2026 10 min read

To convert gold to its 18K (750) equivalent, multiply the weight by its fineness in parts per thousand and divide by 750: 750-equivalent weight = weight × fineness ÷ 750. For per-mithqal pricing you also need to know that one mithqal is 4.608 grams and exactly which karat a quoted rate refers to.

In a jewelry store, gold gallery or wholesale business, items of different purity change hands every day: 18K jewelry, 900 coins, bars and melted gold close to 995, and old gold whose karat still has to be assayed. Until all of these are brought back to a common basis, you cannot add up stock correctly, settle a partner’s account or quote a fair price. This guide explains gold karat conversion, converting mithqal rates to gram rates, and why precision to a thousandth of a gram matters, with worked examples and a ready-made table.

What is gold karat, and why does everything come back to 750?

Karat tells you what share of a piece’s weight is pure gold. There are two common ways of expressing it:

Fineness (parts per thousand): the share of pure gold in every 1,000 units of weight; 750 means 750 thousandths, or 75% pure gold. This is the number usually hallmarked on jewelry.
Karat (K): the share of pure gold out of 24 parts; 18K means 18 parts out of 24, which is exactly 750 fineness.

The relationship is simple: karat = fineness × 24 ÷ 1000. So 585 is 14K, 750 is 18K, 875 is 21K, 916 is 22K and 999 is effectively 24K; 900 works out to 21.6K and 995 to about 23.9K.

Because most jewelry in the Iranian market is 18K, many stores and trade partners there keep stock and gold account balances in “750 equivalent”. Markets where 21K or 22K dominates, as in much of the Gulf and South Asia, may use a different reference karat, but the method is the same. Once everything is expressed in one equivalent, a gram of 995 and a gram of 750 are no longer unrelated figures and can be added up in a single column.

Gold karat conversion table to 18K equivalent

The factor for converting any fineness to 750 is fineness ÷ 750. The table shows the factor for common finenesses and the 750 equivalent of 10 g of each (rounded to three decimals, i.e. to the milligram):

Fineness	Karat (approx.)	Factor to 750	10 g equals how many g of 750?
585	14K	0.78	7.800
705	17K	0.94	9.400
750	18K	1	10.000
875	21K	1.1667	11.667
900	21.6K	1.2	12.000
916	22K	1.2213	12.213
995	23.9K	1.3267	13.267
999.9	24K	1.3332	13.332

If a piece’s fineness is not in the table, apply the same formula; the table is for speed and does not replace the calculation.

The gold karat conversion formula with worked examples

The core formula works in both directions:

From any fineness to 750: 750-equivalent weight = weight × fineness ÷ 750
From 750 to another fineness: weight needed at target fineness = 750 weight × 750 ÷ target fineness

Example 1: converting 900 gold to 750

Say you have 12.5 g of 900 gold. The 750 equivalent is 12.5 × 900 ÷ 750 = 15.000 g. In other words, its pure gold content equals 15 g of 18K gold.

Example 2: converting 995 gold to 18K

Take 3.2 g of 995 gold: 3.2 × 995 ÷ 750 = 4.24533… g, which to the milligram is 4.245 g of 750 equivalent.

Example 3: how much 995 gold settles 15 g of 750?

If you owe a partner 15 g of 750 equivalent and want to settle in 995 gold: 15 × 750 ÷ 995 = 11.3065… g, i.e. about 11.307 g of 995 gold. Which way to round in a case like this is usually a matter of agreement between the two sides, and it is best settled in advance.

Per-gram and per-mithqal gold rates: converting a mithqal rate to grams

One mithqal of gold is 4.608 grams. The mithqal is the traditional weight unit of the Iranian gold market, so 2 mithqals weigh 9.216 g and 5 mithqals 23.04 g. When converting a rate, though, weight is not the only thing that matters: you need to know which karat the mithqal rate is quoted for. In the Iranian market the rate heard as the “mithqal” or mazaneh rate usually refers to melted gold at 705 fineness (about 17K); still, always confirm the basis of any rate with its source before calculating.

To convert a rate per mithqal of 705 into a rate per gram of 750:

Rate per gram of 750 = rate per mithqal of 705 × 750 ÷ (705 × 4.608)

The figure (705 × 4.608 ÷ 750) is about 4.3315, which is why the market rule of thumb is to divide the mithqal rate by roughly 4.33 to get the per-gram 18K rate. For example, at a hypothetical 10,000,000 toman per mithqal of 705, the rate per gram of 750 is about 2,308,658 toman. This number is purely hypothetical and only illustrates the method.

To get the per-gram rate for other finenesses, start from the 750 rate: rate per gram at fineness A = rate per gram of 750 × A ÷ 750. At a hypothetical 5,000,000 toman per gram of 750, the rate per gram of 900 is 6,000,000 toman.

Milligram precision: why rounding too early is expensive

In Iran a thousandth of a gram is called a soot, and it is the smallest unit normally recorded in gold weights and accounts. A difference of a few milligrams on one invoice looks trivial, but over a month and hundreds of invoices and transfers it adds up and puts your gold balance out of line with partners and the cash drawer.

Back to Example 2, at a hypothetical rate of 5,000,000 toman per gram of 750:

Method	750-equivalent weight used	Amount (hypothetical)
Full precision, round only the final amount	4.24533…	21,226,667 toman
Round the weight to the milligram, then multiply	4.245	21,225,000 toman
Round the weight to one decimal	4.2	21,000,000 toman

The gap between the first and third rows on this single item is more than 226,000 toman. The practical rules:

Keep intermediate results at full precision and round only the final result.
Have one fixed rule for rounding weight (to the milligram) and amounts, and put it in writing.
Apply the same rule to buying, selling and partner settlement so neither side feels short-changed.
Record the weight exactly as the scale shows it, and never round it in your head or on paper.

Common mistakes in gold karat and rate conversion

Mixing up karat and fineness: typing “18” where the formula expects “750” makes the result meaningless.
Ignoring the basis of the mithqal rate: if the mithqal rate is quoted for 705 and you treat it as 750, every price is off by about 6%.
Using an approximate mithqal weight: a mithqal is 4.608 g; approximations such as 4.6 or 5 g create noticeable errors on large amounts.
Rounding mid-calculation: the problem shown in the table above.
Recording old or melted gold without assaying: the purity of used and melted gold must be established by assay; guessing the karat hits your gold balance directly.
Different rules for buying and selling: if you use one factor when buying and another when selling, sooner or later you will have a dispute with a customer or partner.

Karat conversion is only one component of the final price. To see how the making charge, seller’s profit and VAT build on top of it, read our gold jewelry price calculation guide with formula and example.

Karat conversion checklist when issuing an invoice

Record each item’s purity as fineness (parts per thousand), not as karat.
Pin down the basis of the day’s rate: per gram or per mithqal, and for which fineness.
Enter the exact scale weight to the milligram.
Calculate the 750-equivalent weight with the formula and show it on the invoice.
Calculate the amount at full precision and round only at the end.
When buying old gold, use the assayed fineness and write it in the invoice description.
At the end of the day, reconcile total 750-equivalent weight in and out against stock.

If you keep weight-based accounts with trade partners, these same conversions are the basis of gold-for-gold settlement and transfers; we cover the details in our article on gold wholesale accounting and weight-based settlement.

How does gold accounting software automate karat conversion?

Doing these calculations by hand on every invoice is slow and error-prone. Zaran gold shop accounting software, built around the promise of being accurate to the last milligram, takes the job over:

Automatic conversion of karats to a standard equivalent and per-gram and per-mithqal pricing, from the entry-level Zaran Start plan.
Sales and purchase invoices with exact weight, karat, making charge and price calculation; and on Zaran Pro, wholesale invoices, gold transfers and weight-based settlement (gold for gold, coin for coin).
Zaran’s wholesale calculations have been matched and tested against tens of thousands of real gold-market records.
On Zaran Elite, invoices with an inconsistent karat, rate or trade direction are flagged automatically, so a conversion or data-entry error is spotted before it turns into a loss.

For the full set of criteria and the features a gold and jewelry accounting system should have, see our complete guide to gold accounting software.

Frequently Asked Questions

What karat is 900 gold?

900 gold is 900 parts per thousand pure gold, equivalent to 21.6 karat. Each gram of it counts as 1.2 grams of 18K (750) gold.

How many grams are in a mithqal of gold?

One mithqal of gold is 4.608 grams. To convert a per-mithqal rate into a per-gram rate, you also need to take into account the fineness the rate is quoted for.

How do I convert 995 gold to 18K?

Multiply the weight by 995 and divide by 750. Each gram of 995 gold is therefore roughly equal to 1.327 grams of 750 gold.

What does “soot” mean in the gold trade?

A soot is the Iranian market term for a thousandth of a gram (a milligram). Gold weights and accounts are usually recorded to three decimal places so that small differences do not pile up over time.

How do I convert a mithqal gold rate into a per-gram 18K rate?

If the mithqal rate is quoted for 705 fineness, divide it by roughly 4.33; the exact formula is mithqal rate × 750 ÷ (705 × 4.608).

Want to see karat conversion, per-gram and per-mithqal rates and milligram-accurate invoices on your own store’s real work? Request a Zaran demo and the P-Soft team will get in touch.