Usual Adult Dose for Iron Deficiency Anemia and Anemia Associated with Chronic Renal Failure:

Initial: 300 to 325 mg of regular-release ferrous sulfate orally once a day.
Maintenance:
Regular-release ferrous sulfate: 325 mg orally 3 times a day. Alternatively, 300 mg orally 4 times a day may be given.
Extended-release ferrous sulfate: 160 mg orally 1 to 2 times a day.

Usual Adult Dose for Vitamin/Mineral Supplementation during Pregnancy/Lactation:

325 mg orally once a day.
The recommended daily allowance (RDA) of elemental iron is 30 mg orally during pregnancy and 15 mg orally during lactation.

Usual Adult Dose for Vitamin/Mineral Supplementation:

325 mg orally once a day.
The recommended daily allowance (RDA) of elemental iron is 10 mg for adult males, 15 mg for adult, premenopausal women, and 10 mg for postmenopausal women.

(Note Ferrous sulfate contains approximately 20% elemental iron)