Grain to Gram Converter (Grains, Carats, Troy Ounces, DWT)
Reviewed by MNM Scales technicians · Updated October 28, 2026
Short answer: 1 grain (gr) is exactly 64.79891 mg, or 0.06479891 g, so 1 gram is about 15.4324 grains. A troy ounce is exactly 480 grains (31.1034768 g), a pennyweight (dwt) is 24 grains (1.55517384 g) and a metric carat (ct) is exactly 200 mg (about 3.0865 gr). These are the exact definitions published by NIST.
Convert a weight Shop precision balances Mail-in calibration
This free converter switches any weight between grains, grams, milligrams, metric carats, pennyweights, troy ounces, avoirdupois ounces, pounds and the tola. Reloaders use it to turn powder charges and bullet weights in grains into grams for metric load data. Jewelers, gold buyers and pawn shops use it to move between carats, pennyweights, troy ounces and grams. Labs and pharmacies use it to move between milligrams, grams and grains. Every factor comes from the unit tables in NIST Handbook 44 (2026), Appendix C. MNM Scales has sold, calibrated and repaired scales and balances for over 30 years and is one of the largest scale distributors, so the scale advice below comes from the same technicians who set these balances up every day.
Weight Unit Converter: grains, grams, carats, dwt, troy ounces
Results show here as you type.
Factors from NIST Handbook 44 (2026), Appendix C: 1 gr = 64.79891 mg exactly, 1 ct = 200 mg exactly. Results are rounded to 11 significant figures. Tola uses the customary 180 gr. Free tool by MNM Scales.
Exact conversion factors (NIST)
Every unit below is defined from the grain or the gram, so each factor is exact. The grain is the shared unit of the avoirdupois, troy and apothecaries systems, which is why one troy ounce (480 gr) is heavier than one ordinary ounce (437.5 gr), while a troy pound (5,760 gr) is lighter than an ordinary pound (7,000 gr).
| Unit | In grains | In grams |
|---|---|---|
| 1 grain (gr) | 1 | 0.06479891 (64.79891 mg) |
| 1 metric carat (ct) | 3.0864717 (approx.) | 0.2 (200 mg) |
| 1 pennyweight (dwt) | 24 | 1.55517384 |
| 1 troy ounce (oz t) | 480 | 31.1034768 |
| 1 ounce, avoirdupois (oz) | 437.5 | 28.349523125 |
| 1 pound, avoirdupois (lb) | 7,000 | 453.59237 |
| 1 gram (g) | 15.4323584 (approx.) | 1 |
| 1 tola (customary, not in the NIST tables) | 180 | 11.6638038 |
Grain to gram conversion table
Common powder charges and bullet weights. Grams = grains × 0.06479891.
| Grains (gr) | Grams (g) | Milligrams (mg) |
|---|---|---|
| 0.1 | 0.0065 | 6.48 |
| 0.5 | 0.0324 | 32.40 |
| 1 | 0.0648 | 64.80 |
| 2 | 0.1296 | 129.60 |
| 5 | 0.3240 | 323.99 |
| 10 | 0.6480 | 647.99 |
| 25 | 1.6200 | 1,619.97 |
| 40 | 2.5920 | 2,591.96 |
| 55 | 3.5639 | 3,563.94 |
| 77 | 4.9895 | 4,989.52 |
| 115 | 7.4519 | 7,451.87 |
| 124 | 8.0351 | 8,035.06 |
| 147 | 9.5254 | 9,525.44 |
| 150 | 9.7198 | 9,719.84 |
| 168 | 10.8862 | 10,886.22 |
| 175 | 11.3398 | 11,339.81 |
| 180 | 11.6638 | 11,663.80 |
| 230 | 14.9037 | 14,903.75 |
| 437.5 | 28.3495 | 28,349.52 |
| 480 | 31.1035 | 31,103.48 |
| 1,000 | 64.7989 | 64,798.91 |
| 7,000 | 453.5924 | 453,592.37 |
Carats, pennyweights and troy ounces to grams
| Weight | Grams (g) | Grains (gr) | Pennyweights (dwt) |
|---|---|---|---|
| 1 point (0.01 ct) | 0.0020 | 0.031 | 0.0013 |
| 0.25 ct | 0.0500 | 0.772 | 0.0322 |
| 0.5 ct | 0.1000 | 1.543 | 0.0643 |
| 1 ct | 0.2000 | 3.086 | 0.1286 |
| 5 ct | 1.0000 | 15.432 | 0.6430 |
| 1 dwt | 1.5552 | 24.000 | 1.0000 |
| 5 dwt | 7.7759 | 120.000 | 5.0000 |
| 10 dwt | 15.5517 | 240.000 | 10.0000 |
| 20 dwt (1 oz t) | 31.1035 | 480.000 | 20.0000 |
| 1 tola | 11.6638 | 180.000 | 7.5000 |
| 1 oz t | 31.1035 | 480.000 | 20.0000 |
| 10 oz t | 311.0348 | 4,800.000 | 200.0000 |
| 100 oz t | 3,110.3477 | 48,000.000 | 2,000.0000 |
Milligrams and grams to grains
| Weight | Grains (gr) | Carats (ct) |
|---|---|---|
| 1 mg | 0.0154 | 0.005 |
| 5 mg | 0.0772 | 0.025 |
| 10 mg | 0.1543 | 0.050 |
| 50 mg | 0.7716 | 0.250 |
| 100 mg | 1.5432 | 0.500 |
| 250 mg | 3.8581 | 1.250 |
| 500 mg | 7.7162 | 2.500 |
| 1 g | 15.4324 | 5.000 |
| 5 g | 77.1618 | 25.000 |
| 10 g | 154.3236 | 50.000 |
| 100 g | 1,543.2358 | 500.000 |
Readability vs. the resolution you need
A balance can only show steps as small as its readability (d), so convert the smallest change you care about into the balance’s unit before you choose one. A practical rule is to pick a readability several times finer than that change.
- Reloading to 0.1 grain: 0.1 gr = 6.48 mg (0.00648 g). A 0.01 g balance moves in steps of about 0.154 gr, which is coarser than 0.1 gr, so it cannot show a 0.1 gr change. A 0.001 g (1 mg) balance moves in steps of about 0.0154 gr, comfortably finer than 0.1 gr. In grain mode the A&D FX-120i reads 0.02 gr.
- Diamonds and gems: 1 point = 0.01 ct = 2 mg. A 0.001 g balance reads 0.005 ct steps; a carat balance with 0.001 ct readability reads 0.2 mg steps.
- Gold and silver by the pennyweight: 0.01 dwt = 15.55 mg, so a 0.01 g balance (about 0.0064 dwt steps) already reads finer than 0.01 dwt. For troy ounces, 0.001 oz t = 31.1 mg.
- Labs and pharmacies: 1 mg = 0.0154 gr. Weighing to the milligram needs a 0.001 g balance, and weighing to 0.1 mg needs an analytical balance with 0.0001 g readability.
When you buy or sell by weight, the balance must also be legal for trade. NIST Handbook 44 Table 7a lists Class II for precious metals and gem weighing, and an NTEP Class II balance such as the A&D FX-120iN or A&D FX-200iN covers it. Their legal-for-trade mode uses g, oz, lb, oz t, ct and dwt; grains are available in A&D standard mode for non-trade work such as reloading. To check how far a reading may drift on a trade scale, use our scale tolerance calculator (NIST Handbook 44).
Pick the right scale for the unit you weigh in
Grains: reloading powder and bullets
- A&D FX-123 Reloading Scale, 122 g x 0.001 g, reads in grains and ships with a 100 g calibration weight. It works with the AutoTrickler V4 (AutoTrickler not included).
- A&D FX-120i Precision Balance, 122 g x 0.001 g, 0.02 gr in grain mode.
- A&D EJ-54D2 Dual-Range Balance, 22 g x 0.0002 g and 52 g x 0.001 g, switches to grains at the press of a key.
Compare all three in our guide to the best reloading scale: FX-123 vs FX-120i vs EJ-54D2.
Carats, pennyweights and troy ounces: jewelry, gold and pawn
- OHAUS SJX323N/E Scout SJX Gold and Carat Scale, 64 g x 0.001 g, NTEP Class II, for stones and small pieces.
- OHAUS SJX1502N/E Scout SJX Gold and Carat Scale, 1,500 g x 0.01 g, NTEP Class II, for scrap gold and silver lots.
- A&D FX-200iN NTEP Precision Balance, 220 g x 0.001 g, legal for trade in g, ozt, ct and dwt.
- Sartorius GCL603I-2S Carat Balance, 600 ct x 0.001 ct with internal calibration, for diamond and gemstone grading.
- A&D EK-1200i NTEP Precision Balance, 1,200 g x 0.1 g, with carat, pennyweight, troy ounce and grain units.
See every NTEP gold and carat balance, or read our guide to choosing a legal-for-trade jewelry scale.
Milligrams and grams: labs and pharmacies
- A&D FX-104 Fortis Analytical Balance, 102 g x 0.0001 g, external calibration.
- A&D GX-124AN Apollo Analytical Balance, 122 g x 0.1 mg, internal calibration, NTEP Class I.
- A&D FX-120i Precision Balance, 122 g x 0.001 g, for milligram work.
Browse all analytical balances and precision balances, or see analytical vs. precision balance to choose the readability you need. Check any balance between calibrations with calibration weights (sold separately).
Keep every reading true: calibration
A converter is only as good as the reading you type in. Our TDA-registered technicians calibrate balances and scales in our Cypress shop, on site across the Houston area, and by mail from anywhere in Texas and from states that accept TDA calibration. For balances up to 2.2 kg capacity, choose in-house calibration with NIST-tested weights ($95) or NIST calibration with a NIST-traceable certificate ($395). Mail-in calibration is usually done 1 to 3 business days after we receive the balance, and covers scales bought elsewhere. On-site service is $295 plus $2 per mile per visit, with calibration priced per scale. Shop visits are by appointment, and we also rent scales of every type.
Book scale calibration in Houston Mail-in scale calibration Call (832) 290-3120
Frequently asked questions
How many grams are in a grain?
One grain is exactly 0.06479891 gram (64.79891 milligrams), as defined in NIST Handbook 44 Appendix C. To convert grains to grams, multiply by 0.06479891. For example, a 168 gr bullet weighs about 10.886 g.
How many grains are in a gram?
One gram is about 15.4324 grains (15.4323584). To convert grams to grains, multiply by 15.4323584 or divide by 0.06479891. For example, 2.85 g of powder is about 44.0 gr.
How many grains are in a troy ounce, and is it the same as a regular ounce?
A troy ounce is exactly 480 grains (31.1034768 g). An ordinary avoirdupois ounce is 437.5 grains (28.349523125 g), so a troy ounce is about 9.7% heavier. Gold, silver and platinum are priced by the troy ounce.
How many grams is a carat?
A metric carat is exactly 200 milligrams (0.2 g), about 3.0865 grains. A carat is divided into 100 points, so one point is 2 mg.
How many grams are in a pennyweight?
One pennyweight (dwt) is exactly 24 grains, or 1.55517384 g, and 20 pennyweights make one troy ounce.
What balance do I need to weigh powder to 0.1 grain?
0.1 grain is 6.48 mg. A balance that reads 0.001 g moves in steps of about 0.015 gr, so it shows a 0.1 gr change clearly, while a 0.01 g balance moves in steps of about 0.15 gr, which is coarser than 0.1 gr. The A&D FX-123 reads directly in grains, and the A&D FX-120i reads 0.02 gr in grain mode.
What is a tola?
The tola is a customary South Asian unit for gold and silver equal to 180 grains, or 11.6638038 g (3/8 of a troy ounce). It is not part of the NIST tables, so this converter uses that common definition.
Source: NIST Handbook 44, 2026 edition, Appendix C, General Tables of Units of Measurement (doi.org/10.6028/NIST.HB.44-2026). The tola is a customary unit outside the NIST tables; this page uses the common definition of 180 grains. Results are rounded for display.