SPF Formulation Calculator

UV filter percentages for target SPF from in-vitro data.

Zinc Oxide (%)

Titanium Dioxide (%)

Avobenzone (%)

Octinoxate (%)

Octocrylene (%)

Batch size (g)

Tab to move between fields

Estimated SPF

28.5

UVB protection (%)

96.5

Broad spectrum? (1=yes)1

Photostable? (1=yes)1

Total UV filters (%)18

Total filter weight (g)18

UVA filters total (%)13

UVB filters total (%)10

How to Use This Calculator

Enter the types and concentrations of UV filters in your sunscreen formula.
Set the formulation vehicle (emulsion, gel, anhydrous).
Review the estimated in-vitro SPF and UVA protection ratio.
Adjust UV filter combinations to achieve the labeled SPF claim.
Note: this provides a formulation estimate -- in-vivo SPF testing per ISO 24444 is required for labeling.

How the result changes with Zinc Oxide (%)

Zinc Oxide (%): Zinc oxide percentage. Broad-spectrum UVA+UVB. FDA max 25%. Contributes ~1.5 SPF per 1%.
Titanium Dioxide (%): Titanium dioxide percentage. Mainly UVB. FDA max 25%. Contributes ~2.0 SPF per 1%.
Avobenzone (%): Avobenzone (Parsol 1789) percentage. UVA filter. FDA max 3%. Contributes ~2.5 SPF per 1%.
Octinoxate (%): Octinoxate (Octyl Methoxycinnamate) percentage. UVB filter. FDA max 7.5%. Contributes ~3.0 SPF per 1%.
Octocrylene (%): Octocrylene percentage. UVB + photostabilizer for avobenzone. FDA max 10%. Contributes ~1.0 SPF per 1%.
Batch size (g): Total batch weight for calculating filter weights.

Estimated SPF: Estimated SPF based on UV filter concentrations. Note: actual SPF requires in-vivo testing.
UVB protection (%): Percentage of UVB radiation blocked. SPF 15=93.3%, SPF 30=96.7%, SPF 50=98%.
Broad spectrum? (1=yes): 1 if the formulation provides meaningful UVA protection (broad spectrum claim).
Photostable? (1=yes): 1 if avobenzone is adequately stabilized by octocrylene or not present.
Total UV filters (%): Combined percentage of all UV filters in the formulation.
Total filter weight (g): Total grams of UV filters needed for the batch.
UVA filters total (%): Combined percentage of UVA-active filters (zinc oxide + avobenzone).
UVB filters total (%): Combined percentage of UVB-active filters.

Identify Input Parameters
4 parameters
Zinc Oxide (%) = 10, Titanium Dioxide (%) = 0, Avobenzone (%) = 3, Octinoxate (%) = 0 = 6 input(s) provided
Calculate Estimated SPF
28.5 = 28.5
Calculate UVB protection
UVB protection = (1 - 1 / max(1, estimatedSpf)) * 100
96.5 = 96.5
Calculate Broad spectrum?
1 = 1
Calculate Photostable?
1 = 1