☀️ Sunscreen Amount Calculator
Based on the SPF-testing standard of 2mg per cm² for one full-body application.
Estimate how much sunscreen (in grams) is needed to cover your whole body at the labeled SPF, based on body surface area (Mosteller formula) and the widely-cited 2mg/cm² application density used in SPF testing. Most people apply noticeably less than this in practice.
How to use
- Enter your height (cm).
- Enter your weight (kg).
- The amount of sunscreen needed for one full-body application is calculated automatically.
FAQ
What does "2mg per cm²" mean?
It's the standard application density used internationally when testing a sunscreen's SPF rating — applying this much achieves the labeled SPF protection. In practice people often apply less, which reduces the effective protection below the labeled SPF.
How is body surface area calculated?
Using the Mosteller formula (body surface area (m²) = √(height (cm) × weight (kg) ÷ 3600)), a formula widely used in medicine.
Can I find the amount needed for just my face?
This tool assumes full-body application. To estimate a specific area like the face, multiply by that area's rough share of total body surface area (the face is often estimated at around 3–3.5% of total).