Folate Needs Calculator: Daily Folate (DFE) and Folic Acid Target
Find your daily folate target in dietary folate equivalents (DFE) by age and life stage (general, trying to conceive, pregnant, breastfeeding), add up food folate, fortified foods and supplements in DFE, see the shortfall and the folic-acid upper limit, and the advised folic-acid supplement.
How it works
DFE = food folate + 1.7 × folic acid from fortified foods or supplements taken with food (2.0 × on an empty stomach) · RDA: 1–3 y 150, 4–8 y 200, 9–13 y 300, 14+ y 400, pregnancy 600, breastfeeding 500 mcg DFE · advised folic acid around conception: 400–800 mcg/day · upper limit (folic acid only): 300–1,000 mcg by age, 1,000 mcg for adults
Folate helps build DNA and forms the baby’s neural tube in the first weeks of pregnancy, often before the pregnancy is known. Targets are set in dietary folate equivalents (DFE) because synthetic folic acid is absorbed better than the folate that occurs naturally in food. One mcg of food folate counts as 1 mcg DFE. One mcg of folic acid from fortified foods or a supplement taken with food counts as 1.7 mcg DFE, and 2 mcg DFE if the supplement is taken on an empty stomach. Choose “Add up my sources” to let the calculator do the conversion. The recommended amount (RDA) from the US Food and Nutrition Board is 400 mcg DFE a day for everyone 14 and over, 600 mcg in pregnancy and 500 mcg while breastfeeding; children need less. Anyone who could become pregnant is advised to take 400 mcg of folic acid a day on top of a varied diet. The US Preventive Services Task Force recommends 400–800 mcg from at least a month before conception through the first 2–3 months of pregnancy. After a pregnancy affected by a neural tube defect, a much higher dose of about 4,000 mcg is used, but only under medical supervision. The upper limit (1,000 mcg for adults) applies only to folic acid from supplements and fortified foods, not to food folate. Regularly going above it can hide a vitamin B12 deficiency.
Worked example
A 30-year-old woman trying to conceive has a target of 400 mcg DFE/day and is advised to take a 400–800 mcg folic-acid supplement. If her diet already supplies 400 mcg DFE, she meets the target (+0 mcg) and the supplement adds a protective margin during the neural-tube window. Using “Add up my sources” with 250 mcg of food folate, 100 mcg of folic acid from fortified foods and a 400 mcg supplement taken with food gives 250 + 170 + 680 = 1,100 mcg DFE (275% of her target). Her folic acid is 500 mcg, half of the 1,000 mcg upper limit.
Sources: NIH Office of Dietary Supplements: Folate fact sheet for health professionals
Frequently asked questions
What is DFE and why use it?
Dietary folate equivalents adjust for absorption. Folic acid from fortified foods or a supplement taken with food counts 1.7 times as much as food folate (2 times on an empty stomach), because the body absorbs it more easily. Targets are set in DFE so you can compare sources fairly.
How much folic acid should I take when trying to get pregnant?
400–800 mcg a day, starting at least one month before conception and continuing through the first 2–3 months of pregnancy. After a previous pregnancy with a neural tube defect, doctors usually prescribe about 4,000 mcg a day.
How much folate do I need in pregnancy?
600 mcg DFE a day from all sources, and 500 mcg DFE while breastfeeding. A prenatal vitamin with 400–800 mcg of folic acid plus a varied diet usually covers it.
Is there a maximum amount of folic acid?
Yes. The upper limit for adults is 1,000 mcg a day of folic acid from supplements and fortified foods (lower for children and teens). It does not apply to natural food folate or to doses a doctor prescribes.
Can I get enough from food alone?
Leafy greens, beans, asparagus, avocado, citrus and fortified grains supply folate. Reaching the target reliably before pregnancy is hard, so a supplement is advised around conception rather than relying on diet alone.
Is methylfolate the same as folic acid?
Methylfolate (5-MTHF) is an active form of folate found in some supplements. It has no official DFE conversion factor, and folic acid is the form proven to prevent neural tube defects in studies.
Related calculators
Educational estimate only, not medical advice. Nutrient needs and pregnancy risks vary between people. Discuss supplements, especially high-dose folic acid, with your doctor, midwife or pharmacist.