Sunscreen calculator

How to use the sunscreen calculator

1. Select each adult's exposed areas. Choose every region that will be uncovered. For packing, count a partly covered region in full, and add a profile for each adult sharing the supply.
2. Pick your task. Use Amount to use for one application, Pack for a trip for a holiday supply, or Bottle life to estimate how long a bottle lasts.
3. Add your schedule and bottle. Enter trip days, hours outdoors, your reapplication plan and bottle size in mL or US fl oz, then copy or print your plan.

How much sunscreen do I need?

Face, neck and ears

Use about 5 mL, or one metric teaspoon, for the face, neck and ears together. This is an adult reference amount for the whole region. It is not a personalized dose for the face alone.

Full adult body

Use about 35 mL, or seven metric teaspoons, when all seven regions are exposed. These are broad reference amounts for adult lotions and creams. A larger body, or product lost while applying, can mean you need more. Cover exposed skin thoroughly and follow your sunscreen label.

The regional amounts follow guidance from Cancer Council Australia and Health Canada. Both use a 35 mL adult total, and Health Canada also reminds you not to miss your ears.

Worked examples for bottles and trips

How long does a 50 mL bottle of sunscreen last?

A 50 mL bottle (about 1.7 US fl oz) holds about 10 complete face, neck and ears applications at 5 mL each. That lasts 10 days at one application a day, or 5 days at two a day. On a full body at 35 mL, the same bottle covers one complete application with 15 mL left. A 100 mL bottle used on the face, neck and ears twice a day lasts about 10 days. These are example inputs, not a recommended schedule. Some product also usually stays in the packaging.

How much sunscreen to pack for 7 or 14 days

Example plan: one adult with all seven regions exposed and 4 hours outdoors each day. The first application goes on 15 minutes before going out, with reapplication every 2 hours in dry conditions. The plan has no extra top-ups and no reserve.

• 3 applications a day: one before you leave, then 1 hour 45 minutes and 3 hours 45 minutes into the outing
• 105 mL a day (3 applications of 35 mL)
• 7 days: 735 mL, or 8 bottles of 100 mL
• 14 days: 1,470 mL, or 15 bottles of 100 mL
• 4 adults on the same 7-day plan: 2,940 mL, or 30 bottles of 100 mL

Bottle counts are rounded up. Changing the areas, hours, interval or number of adults changes the total, so no single bottle count fits every week. The 4-adult figure does not apply to children.