How Long Does Sunscreen Last? Shelf Life, After Opening, and Per Bottle
Unopened sunscreen lasts at least three years — the FDA requires it to stay effective that long, and most bottles carry an expiration date you should follow. Once opened, use it within the same three-year window and toss it sooner if the texture, colour or smell changes or it separates. The bigger real-world issue is under-use: a proper full-body application is about one ounce (a shot glass) reapplied every two hours, so if a single bottle is lasting you multiple summers, you are almost certainly not applying enough to get the SPF on the label.
What skincare costs per ml
Live price terciles across the 100 skincare products we track, by real cost per ml.
| Tier | Cost / ml | Example pick |
|---|---|---|
| Budget | $0.062–$0.19 | NUXE Very Rose Cleansing Foam Light Facial… ($0.16/ml) |
| Mid-range | $0.19–$0.22 | The Ordinary Niacinamide 10% + Zinc 1% ($0.20/ml) |
| Premium | $0.22–$0.25 | Drunk Elephant Pekee Bar - 113 g/4 oz… ($0.24/ml) |
The short answer
Unopened sunscreen lasts at least three years — the FDA requires it to stay effective that long, and most bottles print an expiration date to follow. Once opened, the same window generally applies if you store it well. But the answer people actually need is about use, not shelf life: if one bottle lasts you years, you are not applying enough.
Shelf life: the three-year rule
Sunscreen is a regulated over-the-counter drug, and by FDA rule it must remain stable and effective for three years from manufacture. So:
- Has an expiration date? Use it until then.
- No date printed? Write your purchase date on the bottle and discard three years
later.
- Throw it out early if the colour, smell or texture has changed, or it has separated
and won't remix — those are signs the filters have degraded.
Expired sunscreen loses SPF unevenly, so it can leave you burned even when applied properly. With sun protection, when in doubt, replace it.
Heat is what really kills it
The date on the bottle assumes reasonable storage. A cap left off, or a bottle baking in a hot car or a sunny beach bag, degrades the filters far faster than the calendar suggests. Keep sunscreen in the shade, and don't trust a bottle that spent a summer in a glovebox.
How long a bottle should last
This is where most people go wrong. Proper protection means:
- About one ounce — a shot glass — for a full-body application
- Reapplied every two hours, and after swimming or heavy sweating
That means a single beach day can use 3–4 ounces per person. A typical bottle is only a few ounces, so for a family it may be one or two outings, not a whole summer. For daily facial use (about a quarter teaspoon) a small bottle lasts a couple of months. If your sunscreen lasts for years, you're not using enough to get the SPF on the label.
The cost angle
Because you should use it generously, cost per ounce (or per ml) matters — a big body bottle is far cheaper per application than a small tube of the same SPF, and there's no reason to ration protection to save money. Buy a large, affordable body sunscreen by cost per unit and apply it properly; save the pricey small facial SPF for the face.
Sources
- U.S. Food & Drug Administration — Sunscreen: How to Help Protect Your Skin from the Sun
- American Academy of Dermatology — Sunscreen FAQs
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Frequently asked questions
Does sunscreen expire?
Yes. Sunscreen is a regulated over-the-counter drug, and the FDA requires it to remain stable and effective for at least three years from manufacture. Most bottles print an expiration date — use it until then. If there is no date, write the date you bought it on the bottle and discard it three years later. Expired sunscreen loses SPF strength unevenly, so it can leave you burned even when you apply it correctly.
How long does sunscreen last after opening?
Generally the same three-year shelf life applies, provided you store it well — sunscreen isn't like mascara with a short post-opening window. What shortens it is heat and air: a cap left off, or a bottle baking in a beach bag or car, degrades the filters faster. Toss any opened sunscreen that has changed colour, smell or texture, or that has separated and won't remix, regardless of the date.
How long does a bottle of sunscreen last?
Used correctly, not as long as people think. A full-body application is about one ounce — a shot glass — reapplied every two hours, so a single beach day can use three to four ounces per person. A standard bottle is often only a few ounces, so for a family it can be one or two outings. For daily facial use (about a quarter teaspoon) a small bottle lasts a couple of months. If a bottle lasts you all summer, you are under-applying.
Can I use last year's sunscreen?
If it is within its expiration date, was stored out of heat, and looks and smells normal, yes. If it spent last summer in a hot car or a beach bag in the sun, be cautious — heat is what breaks sunscreen down fastest, and a degraded bottle gives less protection than the SPF claims. When in doubt with sun protection, replace it; a burn costs far more than a new bottle.