Grams To Milligrams Converter

1. Keep the direction on Grams to milligrams, or pick milligrams to grams to reverse it.
2. Type the mass in grams. It can come from a scale display, a recipe or the fine print on a label.
3. Read the milligrams at once. The cards also show the same mass in micrograms, kilograms and ounces.

A milligram (mg) is one thousandth of a gram. It is a metric unit of mass, built by adding the SI prefix milli to the gram. So 1,000 mg make 1 g, and 1,000,000 mg make 1 kg.

NIST lists the full ladder of metric mass units. Ten milligrams make a centigram, ten centigrams make a decigram, and ten decigrams make a gram. Most people skip the middle steps and jump from milligrams straight to grams.

A milligram is very small. A 1 g sugar packet split into 1,000 equal parts gives you pieces of 1 mg each. That is why milligrams show up where tiny amounts matter: nutrients on a food label, active ingredients in a tablet, and samples weighed in a school or research lab.

The symbol is lowercase mg. Capital M means mega, a million, so Mg is a megagram, which is one metric tonne. Mixing the two turns a trace amount into a truckload.

You multiply grams by 1,000, because milli stands for 10^-3 and a gram therefore holds 10^3 milligrams.

1. Write the grams as a number, for example 0.75.
2. Move the decimal point 3 places to the right. Add zeros at the end when you run out of digits: 0.75 becomes 750, and 4 becomes 4,000.
3. Write the unit as mg. Keep the same number of meaningful digits you started with.

Kitchen. A bread recipe lists 0.5 g of saffron threads. 0.5 x 1,000 = 500 mg. A kitchen scale that reads in 1 g steps cannot weigh that, so a 0.01 g pocket scale is the better tool. The baking conversion calculator handles cups and spoons for the rest of the recipe.

Lab. A chemistry student must weigh out 0.0250 g of a salt. That is 25.0 mg. On an analytical balance that reads to 0.0001 g, the last digit is 0.1 mg, so the reading can honestly carry that trailing zero.

Nutrition label. The FDA sample label shows 850 mg of sodium in one serving. 850 / 1,000 = 0.85 g. The FDA Daily Value for sodium is 2,300 mg, which is 2.3 g, so that one serving holds about 37 percent of it.

Reverse. A spice jar says 45 g. That is 45,000 mg, or about 1.587 oz. Grams to ounces is covered in more depth by the ounces to grams converter.

The factor is fixed, so only the reading you start from and the way you write the answer can change the number.

Scale Resolution

A scale can only report what it can resolve. A kitchen scale that reads to 1 g gives milligrams in steps of 1,000. A 0.1 g scale gives steps of 100 mg, a 0.01 g scale gives 10 mg, and a 0.0001 g analytical balance gives 0.1 mg.

Significant Figures

0.5 g and 0.500 g are the same mass but not the same claim. Written as milligrams, they become 500 mg and 500. mg. In lab work, keep the precision of the original reading and do not invent extra digits.

Decimal Comma

Many countries write 0,5 g for half a gram. A reader used to the decimal point could misread 1,500 mg as 1.5 mg. This page uses a point for decimals and commas for thousands.

Label Rounding

Food labels round the numbers they print. The value on a pack is a rounded declaration, not a lab result for your exact serving, so a conversion from it is only as precise as the label.

Grams suit kitchen amounts, milligrams suit small nutrients and lab samples, and micrograms suit trace nutrients such as vitamin B12.

FDA Daily Values in Mg and in G

These are the FDA reference amounts printed on US labels for adults and children 4 and older. They are shown here only as unit examples, not as personal targets.

Reading Nutrition Labels

US labels list fat, carbohydrate and protein in grams, but sodium, potassium, calcium and iron in milligrams. Converting puts both on one scale. It shows, for example, that 2.3 g of sodium and 2,300 mg are the same amount.

Small-batch Cooking and Baking

Yeast, salt, spices and additives in small recipes come out as fractions of a gram. Writing them in milligrams avoids long strings of zeros. It also shows at once whether your scale can weigh them.

School and Lab Work

Balances often display grams, while methods and worksheets ask for milligrams. A quick, exact conversion keeps the lab notebook consistent. From there, the molarity calculator turns a weighed mass into a solution strength.

Every value below is computed from 1 g = 1,000 mg and 1 mg = 1,000 mcg. All values are exact.

1. Dividing Instead of Multiplying

Grams to milligrams makes the number bigger. If 2 g turns into 0.002, you went the wrong way. The right answer is 2,000 mg.

2. Moving the Point Only 2 Places

Multiplying by 100 gives 50 mg for 0.5 g, ten times too little. Milli is a thousandth, so move 3 places.

3. Confusing Mg with Mcg

One milligram is 1,000 micrograms. Reading 500 mcg as 500 mg is a thousandfold error. Always check which prefix a label uses.

4. Writing Mg or MG

Capital M is mega, a million. The milligram symbol is lowercase mg, with no plural s: write 5 mg, not 5 mgs.

5. Mixing Up Gram and Grain

A grain (gr) is 64.79891 mg exactly, not 1 g. The two abbreviations look alike, which is why g and gr must never be swapped.

6. Trusting a Scale Below Its Resolution

A scale that reads to 1 g cannot tell 200 mg from 700 mg. Converting its reading to milligrams does not add precision it never had.

The conversion itself is exact, so any error comes from the mass you measured or the rounding you chose.

There are exactly 1,000 milligrams in 1 gram. The prefix milli means one thousandth, so the factor is fixed by definition.

One tenth of a gram is 100 mg. Move the decimal point 3 places right: 0.100 becomes 100.

Yes. 500 mg divided by 1,000 is 0.5 g, exactly half a gram.

One thousand milligrams is exactly 1 g. Labels sometimes print 1,000 mg where 1 g would be shorter.

US labels list larger nutrients such as fat and protein in grams and smaller ones such as sodium and iron in milligrams. The unit is chosen so the number stays easy to read.

Most kitchen scales read to 1 g, so they cannot. A pocket scale that reads to 0.01 g resolves 10 mg, and only a lab balance reads to 0.1 mg.

Move the decimal point 3 places to the left. 2,500 mg becomes 2.5 g, and 40 mg becomes 0.04 g.

A microgram (mcg) is one thousandth of a milligram. So 1 mg = 1,000 mcg, and 1 g = 1,000,000 mcg.

There is no single answer. A teaspoon is a volume, so its mass in milligrams depends on the density of what you measure. Weigh it instead.

No. The converter runs in your browser and nothing is sent to our servers. Anything you choose to Save stays in this browser only.

• SI units of mass, including the milligram to gram ladder (NIST Office of Weights and Measures).
• Metric SI prefixes, including milli = 10^-3 and micro = 10^-6 (NIST Office of Weights and Measures).
• Daily Values on the Nutrition and Supplement Facts labels, in g, mg and mcg (US Food and Drug Administration).
• How to understand and use the Nutrition Facts label, with the sample label (US Food and Drug Administration).
• Exact factors for the grain and the avoirdupois ounce (NIST SP 811, Appendix B.8).