How to convert milligrams to grams
One milligram equals 0.001 grams, so multiply the number of milligrams by 0.001:
g = mg × 0.001
mg = g ÷ 0.001 (1 g = 1,000 mg)
Example: 100 mg → 100 × 0.001 = 0.1 g.
Going the other way, divide by 0.001, or multiply by 1,000; the grams to milligrams converter does it for you.
Everyday values
| Milligrams | Grams | For example |
|---|---|---|
| 100 mg | 0.1 g | a common low-dose tablet |
| 250 mg | 0.25 g | 250 mg |
| 500 mg | 0.5 g | a common paracetamol tablet |
| 1,000 mg | 1 g | one gram |
When you need this conversion
One gram is 1,000 milligrams. Medicine and nutrient amounts are given in milligrams; always follow the dose on the label or from your doctor and pharmacist, and do not convert doses between products yourself.
Milligram to gram conversion table
| mg | g | mg | g |
|---|---|---|---|
| 50 mg | 0.05 g | 650 mg | 0.65 g |
| 100 mg | 0.1 g | 700 mg | 0.7 g |
| 150 mg | 0.15 g | 750 mg | 0.75 g |
| 200 mg | 0.2 g | 800 mg | 0.8 g |
| 250 mg | 0.25 g | 850 mg | 0.85 g |
| 300 mg | 0.3 g | 900 mg | 0.9 g |
| 350 mg | 0.35 g | 950 mg | 0.95 g |
| 400 mg | 0.4 g | 1,000 mg | 1 g |
| 450 mg | 0.45 g | 1,050 mg | 1.05 g |
| 500 mg | 0.5 g | 1,100 mg | 1.1 g |
| 550 mg | 0.55 g | 1,150 mg | 1.15 g |
| 600 mg | 0.6 g | 1,200 mg | 1.2 g |
About the units
- Milligram (mg): one thousandth of a gram.
- Gram (g): one thousandth of a kilogram.
Both are units of weight (mass). The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many grams are in one milligram?
One milligram is 0.001 grams. One gram is 1,000 milligrams.
How do I convert milligrams to grams?
Multiply the value in milligrams by 0.001. To go back, divide by 0.001.
What is 100 mg in grams?
100 mg = 0.1 g.
What is 250 mg in grams?
250 mg = 0.25 g.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.