Vitamin D Dose Calculator
Daily IU needed based on weight and sun exposure.
Enter your values
Enter the weight in kg.
Choose one of: Plenty (outdoors daily), Moderate, Little or none.
Choose one of: Summer, Spring / autumn, Winter.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Suggested daily dose
- 1,600 IU
- Weekly equivalent
- 11,025 IU
- Upper safe limit (adults)
- 4,000 IU/day
- In micrograms
- 39.4 µg
Quick answer
Typical maintenance is 600-2,000 IU a day, with higher needs at greater body weight and low sun exposure.
dose ≈ weight kg x 25 IU, adjusted for sun exposure
At a glance
| What it does | Daily IU needed based on weight and sun exposure. |
|---|---|
| Category | Health |
| Inputs needed | Weight, Sun exposure, Season |
| Main output | Suggested daily dose |
| Formula | dose ≈ weight kg x 25 IU, adjusted for sun exposure |
| Cost | Free — no sign-up, no download |
How to use the Vitamin D Dose Calculator
- 1Enter your weight and honest sun exposure.
- 2Adjust for the season where you live.
- 3Ask for a blood test if you suspect deficiency rather than guessing long term.
Inputs explained
- Weight(kg)
- Enter the weight in kg.
- Sun exposure
- Choose one of: Plenty (outdoors daily), Moderate, Little or none.
- Season
- Choose one of: Summer, Spring / autumn, Winter.
Worked example
Using the values the calculator loads with:
Inputs
- Weight75 kg
- Sun exposureModerate
- SeasonSpring / autumn
Results
- Suggested daily dose1,600 IU
- Weekly equivalent11,025 IU
- Upper safe limit (adults)4,000 IU/day
- In micrograms39.4 µg
Frequently asked questions
Can I take too much?
Yes. Sustained doses above 4,000 IU without monitoring risk hypercalcaemia.
With or without food?
Vitamin D is fat soluble — take it with a meal containing fat for better absorption.
What do I need to enter into the Vitamin D Dose Calculator?
Just 3 values: weight, sun exposure, season. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Vitamin D Dose Calculator work out the answer?
Typical maintenance is 600-2,000 IU a day, with higher needs at greater body weight and low sun exposure. It applies the formula dose ≈ weight kg x 25 IU, adjusted for sun exposure and shows the working so you can check each step by hand.
Is the Vitamin D Dose Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.