Convert grains to grams

Content last reviewed:2026-09-30

Enter a mass in grains and read the result in grams. One grain is 0.0648 grams, so a 124 gr bullet weighs 8.04 grams. The result appears as you type, and the switch below the fields moves the calculation to the pearl grain used in the natural pearl trade.

Grains (gr)

Grams

Grain type

International: 64.79891 mg, the measure behind bullet, arrow and powder-charge weights. Pearl: 50 mg, a quarter of a carat, the one natural pearls are traded in.

How do you convert grains to grams?

Multiply the number of grains by 0.06479891 and you have the mass in grams. A 124 grain bullet comes out at 8.04 grams.

Formula: grams = grains × 0.06479891

An approximation is enough for mental arithmetic. A grain is a little under seven hundredths of a gram, and the multiplier 0.065 comes out three tenths of a percent above the exact figure.

Take three bullet masses from the pistol ammunition standard. A hundred grains is 6.48 grams. A hundred and fifty grains gives 9.72 grams. Two hundred and thirty grains, the .45 Automatic bullet, weighs 14.90 grams. The standard lists the first two for the 9 mm Luger. All three describe the bullet alone: the case, the powder and the primer carry masses of their own.

The multiplier is exact to the last digit, because the grain has a value fixed directly in metric terms: 64.79891 milligrams[1].

Going the other way you divide by the same multiplier. The grams to grains converter does the whole job for you.

What is a grain, and what is a gram?

A grain is a unit of mass equal to 64.79891 milligrams, or 0.06479891 grams[1]. Its symbol is gr.

The name comes straight from a cereal seed. The reference was the mass of a single barley grain, and average wheat and barley grain masses stood in legal definitions of mass from the Bronze Age through the Renaissance[2].

The grain is also the one unit that holds the same value across all three English systems of mass at once — avoirdupois, troy and apothecaries’[2]. The NIST measurement handbook repeats that sentence above each of its three mass tables[1]. What separates the systems is the number of grains in their pound: 7000 in the avoirdupois pound, 5760 in the troy and apothecaries’ pound. That is the whole of the difference between the avoirdupois pound and the troy pound.

A gram is a thousandth of a kilogram, the base unit of mass in the SI system. One gram holds 15.43 grains, and the grams to milligrams converter takes you a thousand times further down the scale.

The grain still turns up in drug dosages. A standard 325 mg aspirin tablet is sometimes given as 5 grains[2], and five grains work out at 323.99 milligrams, about one milligram under the tablet’s metric figure.

In North America the grain also appears in water hardness figures. Hardness is often stated in grains per US gallon of calcium carbonate equivalent, where one grain per gallon comes to roughly 17.1 parts per million[2].

A case head stamped WINCHESTER 45 AUTO, with a blurred row of cartridges behind it — The case head is stamped WINCHESTER 45 AUTO. For the .45 Automatic the SAAMI standard lists bullets from 120 to 230 grains[3]. In grams that is 7.78 to 14.90 grams. Photo: Cody Wingfield, Unsplash.

How many grams is a given number of grains?

The rows start at one grain and end at seven thousand. They take in single grains, bullet weights, arrow weights, which are also measured in grains[2], and the defining values of the English system of mass. The milligram column is useful for supplements and jewellery, where a result in grams would open with a decimal point and several zeros.

Grains	Grams	Milligrams
1 gr	0.0648 g	64.8 mg
2 gr	0.1296 g	129.6 mg
3 gr	0.1944 g	194.4 mg
4 gr	0.2592 g	259.2 mg
5 gr	0.324 g	323.99 mg
6 gr	0.3888 g	388.79 mg
7 gr	0.4536 g	453.59 mg
7.5 gr	0.486 g	485.99 mg
8 gr	0.5184 g	518.39 mg
10 gr	0.648 g	647.99 mg
12 gr	0.7776 g	777.59 mg
15 gr	0.972 g	971.98 mg
17 gr	1.1016 g	1,101.58 mg
20 gr	1.296 g	1,295.98 mg
21 gr	1.3608 g	1,360.78 mg
22 gr	1.4256 g	1,425.58 mg
23 gr	1.4904 g	1,490.37 mg
24 gr	1.5552 g	1,555.17 mg
25 gr	1.62 g	1,619.97 mg
26 gr	1.6848 g	1,684.77 mg
28 gr	1.8144 g	1,814.37 mg
30 gr	1.944 g	1,943.97 mg
32 gr	2.0736 g	2,073.57 mg
33 gr	2.1384 g	2,138.36 mg
34 gr	2.2032 g	2,203.16 mg
35 gr	2.268 g	2,267.96 mg
40 gr	2.592 g	2,591.96 mg
42 gr	2.7216 g	2,721.55 mg
45 gr	2.916 g	2,915.95 mg
46 gr	2.9807 g	2,980.75 mg
50 gr	3.2399 g	3,239.95 mg
55 gr	3.5639 g	3,563.94 mg
60 gr	3.8879 g	3,887.93 mg
62 gr	4.0175 g	4,017.53 mg
70 gr	4.5359 g	4,535.92 mg
75 gr	4.8599 g	4,859.92 mg
80 gr	5.1839 g	5,183.91 mg
90 gr	5.8319 g	5,831.9 mg
100 gr	6.4799 g	6,479.89 mg
110 gr	7.1279 g	7,127.88 mg
115 gr	7.4519 g	7,451.87 mg
124 gr	8.0351 g	8,035.06 mg
125 gr	8.0999 g	8,099.86 mg
130 gr	8.4239 g	8,423.86 mg
140 gr	9.0718 g	9,071.85 mg
147 gr	9.5254 g	9,525.44 mg
150 gr	9.7198 g	9,719.84 mg
158 gr	10.2382 g	10,238.23 mg
165 gr	10.6918 g	10,691.82 mg
168 gr	10.8862 g	10,886.22 mg
180 gr	11.6638 g	11,663.8 mg
200 gr	12.9598 g	12,959.78 mg
230 gr	14.9037 g	14,903.75 mg
250 gr	16.1997 g	16,199.73 mg
300 gr	19.4397 g	19,439.67 mg
350 gr	22.6796 g	22,679.62 mg
400 gr	25.9196 g	25,919.56 mg
420 gr	27.2155 g	27,215.54 mg
437.5 gr	28.3495 g	28,349.52 mg
480 gr	31.1035 g	31,103.48 mg
500 gr	32.3995 g	32,399.46 mg
650 gr	42.1193 g	42,119.29 mg
750 gr	48.5992 g	48,599.18 mg
1,000 gr	64.7989 g	64,798.91 mg
1,400 gr	90.7185 g	90,718.47 mg
1,500 gr	97.1984 g	97,198.37 mg
2,000 gr	129.5978 g	129,597.82 mg
2,500 gr	161.9973 g	161,997.28 mg
5,760 gr	373.2417 g	373,241.72 mg
7,000 gr	453.5924 g	453,592.37 mg

Four numbers in this table are defining values and follow straight from the way the English system is built. Four hundred and thirty-seven and a half grains make exactly one avoirdupois ounce, four hundred and eighty grains one troy ounce, five thousand seven hundred and sixty grains the troy pound, and seven thousand grains the avoirdupois pound, which is exactly 453.59237 grams.

How many grams does a bullet of a given grain weight come to?

The masses come from the American standard ANSI/SAAMI Z299.3-2022, where the bullet mass column is headed “Nominal Bullet Weight (gr.)”[3]. The standard covers pistol and revolver cartridges, so the table holds the weights for which velocity and pressure are established. Each one is listed with the cartridge the standard names it for.

Bullet weight	Grams	Cartridge
35 gr	2.27 g	25 Automatic
60 gr	3.89 g	32 Automatic
65 gr	4.21 g	380 Automatic
80 gr	5.18 g	380 Automatic
88 gr	5.7 g	9 mm Luger
90 gr	5.83 g	38 Special
93 gr	6.03 g	30 Luger (7,65 mm)
95 gr	6.16 g	9 mm Luger
100 gr	6.48 g	9 mm Luger
101 gr	6.54 g	357 Magnum
110 gr	7.13 g	357 Magnum
115 gr	7.45 g	9 mm Luger
120 gr	7.78 g	45 Automatic
124 gr	8.04 g	9 mm Luger
125 gr	8.1 g	40 Smith & Wesson
130 gr	8.42 g	38 Special
135 gr	8.75 g	10 mm Automatic
140 gr	9.07 g	357 Magnum
147 gr	9.53 g	9 mm Luger
148 gr	9.59 g	38 Special
155 gr	10.04 g	10 mm Automatic
158 gr	10.24 g	38 Special
165 gr	10.69 g	40 Smith & Wesson
170 gr	11.02 g	10 mm Automatic
175 gr	11.34 g	45 Automatic
180 gr	11.66 g	44 Remington Magnum
185 gr	11.99 g	45 Automatic
200 gr	12.96 g	45 Automatic
210 gr	13.61 g	44 Remington Magnum
220 gr	14.26 g	45 Automatic
230 gr	14.9 g	45 Automatic
240 gr	15.55 g	44 Remington Magnum
250 gr	16.2 g	44 Remington Magnum
275 gr	17.82 g	44 Remington Magnum
300 gr	19.44 g	44 Remington Magnum

The number on the box is a nominal mass and the standard allows a tolerance around it[3]. For lead and lead-core bullets under 100 grains it is ±2.0% of nominal weight, from 100 grains upwards ±1.5%, and for bullets of principally non-lead construction ±3.0%. A lead-core bullet described as 124 gr therefore sits between 122.14 and 125.86 grains, which is 7.91 to 8.16 grams.

How much did a grain weigh in different systems of measurement?

Two of these values are current. The international grain gives the mass of bullets, powder and arrows, while the pearl grain serves the natural pearl trade: the jewellery confederation CIBJO defines it as a quarter of a carat[4], and a carat is 200 milligrams. The remaining six rows describe systems from before metrication, in which the same name covered masses from 12.7 to 835 milligrams.

Kind of grain	Mass	Where it applied
International grain	64.79891 mg	today: bullets, powder, arrows
Pearl grain	50 mg	today: the natural pearl trade
Nuremberg apothecaries’ grain	about 62 mg	German pharmacies before metrication
Grain of the poids de marc	about 53.114 mg	France before metrication
Venetian grano	about 52 mg	the Republic of Venice
Grano castellano	49.914 mg	old Castile
Assay grain of the Cologne mark	12.7 mg	metal assaying
Polish gran	835 mg	Poland, 16th to 18th century

The Nuremberg apothecaries’ grain was a twentieth of a scruple and a 5760th of the apothecaries’ pound, and under the Cologne mark the assay grain came to 12.7 milligrams[5]. The French grain sat inside the poids de marc as 1/72 of a gros[6], the Venetian grano applied across the territory of the Republic[7], and the grano castellano belonged to the old Castilian system[8]. The switch below the converter fields covers the two values in use today: the international one and the pearl one.

Which number formats does this converter handle?

Paste the number the way you have it: with a comma, with a point, with a space between thousands, as a fraction or next to a unit symbol. The field reads every one of these formats and converts it for you, and the table shows exactly what it does with each. The converter computed the results itself.

What you type	What the converter shows	How we read it
124.5	8.0675 g	The decimal point from the numeric keypad, written the way English writes it
124,5	8.0675 g	A comma pasted from a market that writes decimals that way is read as a decimal point, so the result is the same
1,500	97.1984 g	Three digits follow the comma, so we read it as a thousands separator: the field holds one thousand five hundred. A note under the field shows the other possible reading, 1.5.
1 000	64.7989 g	A space between thousands, the way a spreadsheet pastes it, does not split the number in two
3/4	0.0486 g	We work the fraction out ourselves, so there is no need to turn it into a decimal first
115½	7.4843 g	The ½ character copied from a recipe or a label is added to the number in front of it
124.5 gr	8.0675 g	A unit symbol pasted along with the number is no trouble: we take the number and leave the symbol out

How do you convert grains to grams in a spreadsheet?

One multiplication is all it takes. With the number of grains in cell A1, type =A1*0.06479891 in the next cell and you have grams.

Excel also has a ready function that knows unit names. It is called CONVERT and its syntax is CONVERT(number,from_unit,to_unit)[9].

The unit symbol is always written in English and is case-sensitive[9]. The grain is "grain" and the gram is "g", so the whole conversion reads =CONVERT(A1,"grain","g").

The same function takes the other units of mass. =CONVERT(A1,"grain","ozm") gives the same mass in avoirdupois ounces, and =CONVERT(A1,"g","grain") counts the other way.

The result runs long, because the multiplier carries eight decimal places. ROUND sets the number of digits: =ROUND(A1*0.06479891,4) leaves four decimals, matching the result field above.

Convert other units to Grams

lb to g kg to g mg to g mcg to g carats to g oz to g tons to grams

Sources

NIST Handbook 44 (2023), Appendix C. General Tables of Units of Measurement — National Institute of Standards and Technology
Grain (unit) — Wikipedia
ANSI/SAAMI Z299.3-2022. Voluntary Industry Performance Standards for Pressure and Velocity of Centerfire Pistol and Revolver Ammunition — Sporting Arms and Ammunition Manufacturers’ Institute
The Pearl Book, Pearl Commission 2024-1 — CIBJO — The World Jewellery Confederation
Gran (Einheit) — Wikipedia
Grain (unité) — Wikipedia
Grano (unità di misura) — Wikipedia
Grano (unidad de masa) — Wikipedia
CONVERT function — Microsoft

Every figure in the tables was computed from the unit definitions and checked arithmetically before publication. Historical values and the names of local units come from the sources listed above.

Content last reviewed: September 30, 2026 · written and checked by the Arteon team

Common questions about converting grains to grams

How many grams is one grain?

One grain is 0.06479891 grams, or 64.79891 milligrams. The value is fixed directly in metric terms, so the conversion is exact to the last digit. The other way round, one gram holds 15.43 grains.

What does gr mean on an ammunition box?

The grain. The SAAMI standard heads its bullet mass column with that very abbreviation: “Nominal Bullet Weight (gr.)”. The symbol for the gram is a single g, so one letter and a factor of fifteen separate the two.

Why is bullet weight given in grains?

Because the grain is conveniently small. A pistol bullet weighs somewhere between a few and almost twenty grams, so in grains it becomes a three-digit number in which a one percent difference shows without a decimal point. The SAAMI standard lists bullet mass in grains.

Does a troy grain weigh the same as an avoirdupois grain?

Yes. NIST repeats that sentence above each of its three mass tables: the grain is an equivalent quantity in avoirdupois, troy and apothecaries units of mass. What separates the systems is the number of grains in the pound — 7000 for avoirdupois, 5760 for troy and apothecaries.

What is the pearl grain and when should you pick it?

The pearl grain is a unit of the natural pearl trade, equal to a quarter of a carat, which is 50 milligrams. Move the switch below the fields to it when the mass comes from a pearl valuation or a strand description. Bullets, powder and arrows stay with the international grain.

How many grains are in an aspirin tablet?

A standard 325 mg tablet is sometimes given as 5 grains. Five grains work out at 323.99 milligrams, so the two figures describe the same tablet to within about one milligram.

What is the difference between a grain and a gram?

Scale and origin. The gram is a thousandth of a kilogram, the base unit of the SI system, while the grain comes from the English system of measurement. One gram holds 15.43 grains, and one grain is 0.0648 grams.

Arteon free tool screenshot: Convert grains to grams

Help us improve these tools

Have an idea for a feature, found a bug or want to suggest another tool? Write to us.