Magnesium Daily Value: 420 mg
The FDA Daily Value for magnesium is 420 mg for adults and children 4+.
Key facts
- Adults & children 4+
- 420 mg
- Ages 1–3
- 80 mg
- Pregnant/lactating
- 400 mg
- Infants
- 75 mg
- On labels until 2020/2021
- 400 mg · increased Source (opens in a new tab)
- Label rounding
- Regulation: in mg, to the precision of the Daily Value; more decimals allowed for small amounts; under 2% DV may show 0% FDA guidance (nonbinding): nearest 5 mg
- 20% DV (high)
- 84 mg
Common amounts of magnesium
Per serving, adults and children 4+.
- 20 mg is 4%
- 50 mg is 10%
- 100 mg is 25%
- 200 mg is 50%
- 500 mg is 120%
Magnesium Daily Value: 80 mg
The FDA Daily Value for magnesium is 80 mg for children 1–3 years.
- Adults & children 4+
- 420 mg
- Ages 1–3
- 80 mg
- Pregnant/lactating
- 400 mg
- Infants
- 75 mg
- Label rounding
- Regulation: in mg, to the precision of the Daily Value; more decimals allowed for small amounts; under 2% DV may show 0%
- 20% DV (high)
- 16 mg
Per serving, children 1–3 years.
- 5 mg is 6%
- 10 mg is 15%
- 20 mg is 25%
- 50 mg is 60%
- 100 mg is 130%
Magnesium Daily Value: 400 mg
The FDA Daily Value for magnesium is 400 mg for pregnant and lactating women.
- Adults & children 4+
- 420 mg
- Ages 1–3
- 80 mg
- Pregnant/lactating
- 400 mg
- Infants
- 75 mg
- Label rounding
- Regulation: in mg, to the precision of the Daily Value; more decimals allowed for small amounts; under 2% DV may show 0%
- 20% DV (high)
- 80 mg
Per serving, pregnant and lactating women.
- 50 mg is 15%
- 100 mg is 25%
- 200 mg is 50%
- 500 mg is 130%
Magnesium Daily Value: 75 mg
The FDA Daily Value for magnesium is 75 mg for infants through 12 months.
- Adults & children 4+
- 420 mg
- Ages 1–3
- 80 mg
- Pregnant/lactating
- 400 mg
- Infants
- 75 mg
- Label rounding
- Regulation: in mg, to the precision of the Daily Value; more decimals allowed for small amounts; under 2% DV may show 0%
- 20% DV (high)
- 15 mg
Per serving, infants through 12 months.
- 5 mg is 6%
- 10 mg is 15%
- 20 mg is 25%
- 50 mg is 70%
- 100 mg is 130%
Questions about magnesium
What is the FDA Daily Value for magnesium?
The FDA Daily Value for magnesium is 420 mg for adults and children 4 years and older. On a Nutrition Facts label, a serving's %DV for magnesium is its amount divided by 420 mg, times 100.
How do I work out the %DV for magnesium?
Divide the amount in one serving by 420 mg and multiply by 100. Then round to the nearest 2% up to 10%, to the nearest 5% above 10% and up to 50%, and to the nearest 10% above 50%. For example, 84 mg ÷ 420 mg × 100 = 20%.
How are vitamin and mineral %DV values rounded?
The percentages for vitamins and minerals shall be expressed to the nearest 2-percent increment up to and including the 10-percent level, the nearest 5-percent increment above 10 percent and up to and including the 50-percent level, and the nearest 10-percent increment above the 50-percent level.
Magnesium rounding rules
Amount
Magnesium is declared to the nearest 5mg. Measuring finer than that changes nothing on the label, except below 2.5mg, where it is declared to the nearest 1mg so a real amount is not printed as 0.
| Amount range | Rounding rule |
|---|---|
| 0 to <2.5 | nearest 1 mg |
| ≥2.5 | nearest 5 mg |
These mg increments come from FDA guidance, banded by this group's Daily Value.
% Daily Value
| %DV range | Rounding rule |
|---|---|
| 0 to 10% DV | Nearest 2% |
| >10 to 50% DV | Nearest 5% |
| >50% DV | Nearest 10% |
Every %DV a label can show
What a serving has to contain for a label to print each figure. The %DV is worked out from the actual amount, before that amount is rounded.
| If the label shows | The serving must contain |
|---|---|
| Nearest 2%0 to 10% DV | |
| 0% DV | 0 mg≤ amount <4.2 mg |
| 2% DV | 4.2 mg≤ amount <12.6 mg |
| 4% DV | 12.6 mg≤ amount <21 mg |
| 6% DV | 21 mg≤ amount <29.4 mg |
| 8% DV | 29.4 mg≤ amount <37.8 mg |
| 10% DV | 37.8 mg≤ amount <52.5 mg |
| Nearest 5%>10 to 50% DV | |
| 15% DV | 52.5 mg≤ amount <73.5 mg |
| 20% DV | 73.5 mg≤ amount <94.5 mg |
| 25% DV | 94.5 mg≤ amount <115.5 mg |
| 30% DV | 115.5 mg≤ amount <136.5 mg |
| 35% DV | 136.5 mg≤ amount <157.5 mg |
| 40% DV | 157.5 mg≤ amount <178.5 mg |
| 45% DV | 178.5 mg≤ amount <199.5 mg |
| 50% DV | 199.5 mg≤ amount <231 mg |
| Nearest 10%>50% DV | |
| 60% DV | 231 mg≤ amount <273 mg |
| 70% DV | 273 mg≤ amount <315 mg |
| 80% DV | 315 mg≤ amount <357 mg |
| 90% DV | 357 mg≤ amount <399 mg |
| 100% DV | 399 mg≤ amount <441 mg |
The rules are FDA's; the inversion is ours. Ranges are inclusive at the low end and exclusive at the high end, because an exact half rounds up.
Does the magnesium Daily Value change for children or pregnancy?
Yes. It is 80 mg for children 1 to 3 years, is 400 mg during pregnancy and lactation and is 75 mg for infants through 12 months.
How do I find out how much magnesium is in a food?
A Daily Value is a reference target, not a measurement of any particular food. To find the magnesium content of a specific ingredient or product, look it up in USDA FoodData Central, then use that amount here to see what a label would declare and what %DV it carries.
Where do these numbers come from?
- Daily Values and label rounding: FDA, 21 CFR 101.9, as of 2026-02-12.
- Magnesium Daily Value: 21 CFR 101.9(c)(8)(iv).
- Magnesium label rounding: 21 CFR 101.9(c)(8)(iii).
- %DV rounding: 21 CFR 101.9(c)(8)(iii).
- Old Daily Values: 21 CFR 101.9, April 1, 2016 edition.
- 5% low and 20% high: FDA's consumer page on the lows and highs of %DV.
- Dataset: bm-regulatory US Nutrition Label Rules v17.0.0.
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