Tanning calculator

Very high UV

Find your row and your column. The number estimates how many minutes of unprotected sun it takes before the first redness appears — 0.667 × MED ÷ UV, the standard erythemal formula. At UV 8, that is 17 min for type I and 50 min for type VI.

These are weather-based estimates, not personal safety limits. There is no risk-free tan: skin damage builds up before any redness shows, and these times assume unprotected skin under a clear sky. Read them as when to come in, never as time you are entitled to use up — and do not rely on them at all for children, or if you have a history of skin cancer, a skin condition, or take photosensitising medication.

Tomorrow in Columbus

peak UV 6.6 at 13:00 · type II has about 25 min of unprotected sun before the first redness at the peak · protection recommended (WHO) 10:35–16:08

High UV

13:00 Peak UV hour tomorrow
25 min Est. first redness at peak, type II
10:35–16:08 Protection recommended (UV 3+, WHO)

Protection recommended (UV 3+, WHO) UV index

Estimated minutes of unprotected sun before the first redness in Columbus, by skin type. An estimate, not a safety limit — skin damage builds up before any redness shows. The sun has already set where you are, so these are tomorrow’s figures.
Skin type	At peak UV 6.6
I	20 min
II	25 min
III	30 min
IV	40 min
V	51 min
VI	61 min

Every UV level against every skin type

Estimated minutes of unprotected sun before the first redness. Red cells are under 20 minutes. No cell is an all-clear — damage starts before the redness does.
UV	Type I	Type II	Type III	Type IV	Type V	Type VI
UV 1	2 h 13	2 h 47	3 h 20	4 h 27	5 h 33	6 h 40
UV 2	67 min	83 min	1 h 40	2 h 13	2 h 47	3 h 20
UV 3	44 min	56 min	67 min	89 min	1 h 51	2 h 13
UV 4	33 min	42 min	50 min	67 min	83 min	1 h 40
UV 5	27 min	33 min	40 min	53 min	67 min	80 min
UV 6	22 min	28 min	33 min	44 min	56 min	67 min
UV 7	19 min	24 min	29 min	38 min	48 min	57 min
UV 8	17 min	21 min	25 min	33 min	42 min	50 min
UV 9	15 min	19 min	22 min	30 min	37 min	44 min
UV 10	13 min	17 min	20 min	27 min	33 min	40 min
UV 11	12 min	15 min	18 min	24 min	30 min	36 min

With sunscreen

SPF slows the dose; it does not buy a proportional number of hours. Reapplication every two hours and the amount actually applied decide the real protection, and the pages below say so level by level.

Every UV level

Is it good for tanning? The straight answers

Every skin type

Where the sun is strongest right now

Darwin — UV 12.2Extreme · Australia · peak at 12:30 · type II: 14 min to first redness at the peak
Cairns — UV 11.2Extreme · Australia · peak at 13:00 · type II: 15 min to first redness at the peak
Brisbane — UV 8.4Very high · Australia · peak at 12:00 · type II: 20 min to first redness at the peak

How the calculator works

How does this calculator work?

It uses the standard erythemal formula: minutes before the first redness = 0.667 × MED ÷ UV index, where MED is the minimal erythemal dose of your skin type (200 J/m² for type I up to 600 J/m² for type VI). It is a simple deterministic model applied to a public weather forecast — a fixed dose per skin type, plus corrections for cloud, altitude and ground reflection.

What do I need to know to use it?

Two things: the UV index where you are, which the chart on this page reads from the forecast automatically, and your Fitzpatrick skin type, which you can identify from what happens after thirty minutes of strong unprotected sun. Everything else follows.

Does a low UV index mean it is safe to tan?

No. A tan is the skin's response to UV damage, so no level is risk-free — a lower index only slows the accumulation. Below UV 2 the skin produces no melanin at all, and from UV 3 the WHO recommends protection for every skin type. The numbers here estimate when visible redness starts, which is a point to stay under rather than a target to reach.

Does the calculator account for cloud, altitude and reflection?

Yes. Cloud cover comes from the forecast and is applied with the standard attenuation curve — a fully overcast sky removes about 75% of the UV, a half-covered one only about 7%. Altitude adds 12% per 1,000 m. Dry sand adds about 15%, water about 20%, fresh snow up to 80%.