SPF calculator
How much sun protection are you actually getting? Most people apply about a quarter of the recommended amount – and that cuts the effectiveness of their sunscreen dramatically. Work out your real protection.
1. What is your skin phototype?
Fair skin, blond or light brown hair. Burns easily, tans minimally.
3. How much do you apply?
Very littleNot muchA good amountThe recommended amount
~1 mg/cm² – half the recommended amount
Your real protection
5
Effective SPF
50 min
Recommended time before reapplying
You think you have SPF 30 (blocking 96.7 % of UV), but you are actually getting only SPF 5 (blocking 80.0 % of UV). Apply more product for full protection.
- SPF on the label
- SPF 30
- Effective SPF
- SPF 5
- Total protection
- 50 min
- Reapply after
- 50 min
Tip: how much is “the right amount”?
Your face and neck need roughly ½ a teaspoon (about 1.25 ml). Your whole body needs about 6 teaspoons (about 35 ml). Most people apply only 25–50 % of the recommended amount.
Frequently asked questions
- How much SPF do I actually need?
- For an ordinary day SPF 30 is enough – it blocks 97 % of UVB. SPF 50 blocks 98 %. Applying enough and reapplying regularly matters far more than the number on the bottle.
- Why is my real protection lower than the SPF on the label?
- The SPF on the label is tested with 2 mg/cm² of product. Most people apply only 0.5–1 mg/cm², a quarter to a half of that. At half the amount, SPF 50 drops to roughly SPF 7.
- How often should I reapply sunscreen?
- At least every two hours while you are outdoors. Reapply immediately after swimming, sweating or towelling off, even with a water-resistant product.
- Is the SPF in my day cream or foundation enough?
- SPF in a day cream or foundation is better than nothing, but you usually apply far too little for full protection. For a whole day outdoors use a dedicated sunscreen.