Vitamin D Needs Calculator Formula
Understand the math behind the vitamin d needs calculator. Each variable explained with a worked example.
Formulas Used
Recommended Vitamin D
vitamin_d_iu = round(base_iu * sun_exposure * (weight_lbs / 150))In Micrograms
vitamin_d_mcg = round(base_iu * sun_exposure * (weight_lbs / 150)) / 40Variables
| Variable | Description | Default |
|---|---|---|
age | Age(years) | 35 |
weight_lbs | Body Weight(lbs) | 170 |
sun_exposure | Weekly Sun Exposure | 1 |
base_iu | Derived value= age <= 70 ? 600 : 800 | calculated |
How It Works
Vitamin D Requirement Estimation
Vitamin D requirements vary by age, body weight, and sun exposure. The RDA is 600 IU for ages 1-70 and 800 IU for those over 70.
Adjusted Formula
Vitamin D (IU) = Base IU x Sun Factor x (Weight / 150)
This adjusts the base RDA for body size and sun exposure, since vitamin D is produced in the skin when exposed to sunlight.
Worked Example
A 35-year-old, 170 lbs, with moderate sun exposure.
age = 35weight_lbs = 170sun_exposure = 1
- 01Base IU (age <= 70) = 600
- 02Adjusted = 600 x 1.0 x (170 / 150)
- 03= 600 x 1.133 = 680 IU/day
- 04In mcg = 680 / 40 = 17.0 mcg
Ready to run the numbers?
Open Vitamin D Needs Calculator