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The tolerable upper intake level (UL), or upper limit, for folic acid is 1,000 mcg a day for adults 19 and older. That is the most a day that is unlikely to cause harm for almost everyone; above it, the chance of side effects goes up. It is a ceiling, not a target. The limit counts only synthetic folic acid from supplements and fortified foods, not the folate naturally in food.
Check your amount
Servings a day
This limit is the same for adults 19 and older, including pregnancy and breastfeeding.
Type the amount from your label to compare it with the upper limit.
Take more than one supplement? Add them all up in the Supplement Checker.
Folic Acid upper limits by age
| Age | Males | Females | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| Birth to 6 months | Not set | Not set | – | – |
| 7-12 months | Not set | Not set | – | – |
| 1-3 years | 300 mcg | 300 mcg | – | – |
| 4-8 years | 400 mcg | 400 mcg | – | – |
| 9-13 years | 600 mcg | 600 mcg | – | – |
| 14-18 years | 800 mcg | 800 mcg | 800 mcg | 800 mcg |
| 19-30 years | 1,000 mcg | 1,000 mcg | 1,000 mcg | 1,000 mcg |
| 31-50 years | 1,000 mcg | 1,000 mcg | 1,000 mcg | 1,000 mcg |
| 51-70 years | 1,000 mcg | 1,000 mcg | – | – |
| 71+ years | 1,000 mcg | 1,000 mcg | – | – |
No upper limit could be set for babies; the National Academies say their intake should come from food and formula only.
How much Folic Acid you need
| Age | Males | Females | Pregnancy | Breastfeeding |
|---|---|---|---|---|
| Birth to 6 months | 65 mcg* | 65 mcg* | – | – |
| 7-12 months | 80 mcg* | 80 mcg* | – | – |
| 1-3 years | 150 mcg | 150 mcg | – | – |
| 4-8 years | 200 mcg | 200 mcg | – | – |
| 9-13 years | 300 mcg | 300 mcg | – | – |
| 14-18 years | 400 mcg | 400 mcg | 600 mcg | 500 mcg |
| 19-30 years | 400 mcg | 400 mcg | 600 mcg | 500 mcg |
| 31-50 years | 400 mcg | 400 mcg | 600 mcg | 500 mcg |
| 51-70 years | 400 mcg | 400 mcg | – | – |
| 71+ years | 400 mcg | 400 mcg | – | – |
* Adequate Intake (AI): the amount set when there isn’t enough evidence for an RDA.
What counts toward the Folic Acid limit
The limit counts only synthetic folic acid from supplements and fortified foods, not the folate naturally in food.
Labels list folate in mcg DFE and, when it is folic acid, the folic acid amount in parentheses. The limit is in mcg of folic acid: from a supplement taken with food, 1 mcg of folic acid is about 1.7 mcg DFE.
What happens with too much Folic Acid
The National Academies' 1998 DRI report says excess folate intake "may precipitate or exacerbate neuropathy in vitamin B12-deficient individuals" and that too much from folate supplements "may obscure or mask and potentially delay the diagnosis of vitamin B12 deficiency". The report based the UL on case studies of worsening neurological effects in B12-deficient patients taking folate supplements.
Sources: Health Canada, Dietary Reference Intakes tables (the joint U.S.-Canada values); National Academies, Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998); National Academies, Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998). Limits checked November 8, 2026. More from the NIH: Office of Dietary Supplements Folic Acid fact sheet.
If you think you or a child took too much of a supplement, call Poison Control at 1-800-222-1222 (U.S., free, 24 hours) or use poison.org. In an emergency, call 911.
General information, not medical advice. Your doctor may recommend a different amount, for example to treat a deficiency. Talk to your doctor or pharmacist before you start, stop or change a supplement, especially if you are pregnant, nursing, take medication or have a medical condition.