How to Apply Sunscreen Properly – How Much, How Often, and SPF 30 vs SPF 50

In a country with some of the highest UV levels in the world, you’d think Australians would be experts at sunscreen. And yet studies have repeatedly found that most people apply far less than the amount used to test the SPF on the label. The result is that real-world protection is often well below what the bottle promises. The good news is that getting it right is simple. This guide covers how much to use, when to apply, when to reapply, and how to think about SPF 30 versus SPF 50.

Why the amount matters so much

SPF is tested in a laboratory using a specific amount of sunscreen on the skin, about 2 milligrams per square centimetre. That’s a lot more than most of us put on. When people apply half the tested amount, the protection they get can drop well below the labelled SPF, and it doesn’t scale in a simple, gentle way. In other words, under-applying a high-SPF product can leave you with the protection of a much lower one.

The practical takeaway is this: the amount you apply and how often you reapply matter at least as much as the SPF number itself.

How much sunscreen should you use?

The Cancer Council’s guidance for an average adult is about 35 millilitres, or seven teaspoons, for a full body application. A simple way to remember it is one teaspoon (about 5 ml) for each of these areas:

• Head, face and neck
• Front of the torso
• Back of the torso
• Each arm (one teaspoon per arm)
• Each leg (one teaspoon per leg)

That adds up to seven teaspoons for the whole body. If you’re wearing a swimsuit and shorts, you’ll use less, because you only need to cover exposed skin. For children, scale down according to size, but be generous.

Two easy checks: first, if a bottle you’ve been using daily lasts for months, you’re probably using too little. Second, a small dab that disappears into the skin after a single rub is rarely enough.

When to put it on

You would have heard the rule of applying sunscreen about 20 minutes before you go outside. Apply all sunscreens according to the label, generally 20 minutes before going outside. This gives you time to check for missed spots.

Apply it to clean, dry skin as the last step of your skincare routine, before makeup. If you use moisturiser, give it a few minutes to settle first.

Don’t forget the usual missed spots

When sunburn shows up in a surprising place, it’s usually one of these:

• Ears, especially the tops and the backs.
• Back of the neck and the hairline.
• Tops of the feet and the toes.
• Hands, which are exposed to UV every time you drive.
• Lips, where a lip balm with SPF helps.
• Part lines and thinning hair, where a hat is the best option.
• Under straps and swimwear edges, which shift as you move.

The back of your own body is hard to reach. If you’re at the beach, ask a friend or use a hat and rash vest, which are far more reliable than trying to contort yourself.

How often should you reapply?

The rule of thumb in Australia is to reapply at least every two hours, and straight away after swimming, towel drying or heavy sweating. This applies even to water-resistant products. “Water resistant” on a label means the SPF holds up for a stated time in water (as specified on the Australian product label), not that the sunscreen is permanent.

Reapplying doesn’t give you extra time in the sun. Sunscreen should never be used to stay out longer than you otherwise would. Think of the two-hour rule as maintaining your protection, not topping up your allowance.

If you wear sunscreen under makeup, make a plan to reapply a full, even application as directed. Hats and sunglasses provide additional protection, rather than replacing sunscreen.

SPF 30 vs SPF 50: is there a big difference?

A lot of people assume SPF 50 offers almost twice the protection of SPF 30. It doesn’t. The numbers describe how much UVB is filtered out:

So SPF 50 lets through roughly 2% of UVB, compared with roughly 3.3% for SPF 30. That’s a real but modest difference. It matters most for people at higher risk, such as those with very fair skin, a history of skin cancer, or spending long periods outdoors at the beach or on a farm.

The TGA advises SPF 30 or higher; Cancer Council recommends SPF 50 or SPF 50+, broad-spectrum and water-resistant. What counts in practice is that you use enough, apply it evenly and reapply on schedule. A well-applied SPF 30 will protect you better than a thinly applied SPF 50. Our formula is SPF 30 broad-spectrum, built around non-nano zinc oxide, and it’s designed to be nice enough to wear that you’ll actually use plenty.

When do you need sun protection?

Sunscreen isn’t only for summer or sunny days. UV is invisible, and it doesn’t correspond to temperature. Sun protection is recommended whenever the UV Index reaches 3 or above, which happens across most of Australia for much of the year, including many winter days in northern areas. Cloud can block heat and light, but a large share of UV can still get through.

The simplest approach is to check the UV forecast on the Bureau of Meteorology website or in a SunSmart app, and build sunscreen into your morning routine when the Index is 3 or higher.

Sunscreen is one part of the plan

No sunscreen blocks 100% of UV, so it works best alongside other protection:

• Seek shade, especially between 10 am and 3 pm in daylight saving months, when UV is usually strongest.
• Cover up with long, loose, tightly woven clothing.
• Wear a broad-brimmed hat that protects your face, ears and neck.
• Wear sunglasses that meet the Australian standard.
• Apply sunscreen to skin that can’t be covered.

This is the familiar Slip, Slop, Slap, Seek, Slide message. It has been a cornerstone of Australian sun safety for decades for good reason.

A simple daily routine

If you want an easy habit to build, try this:

• Check the UV Index with your morning weather.
• Apply one teaspoon to your face and neck, plus any exposed arms and legs.
• Pop a travel-size sunscreen in your hand bag, sports bag, school bag, or desk drawer, so it’s always within reach. We say keep one in every go-to spot.
• Set a two-hour reminder if you’re outdoors for an extended period.
• Wear a hat and sunglasses to share the load.

Common questions

How much sunscreen should I put on my face?

About one teaspoon covers the head, face and neck for most adults. Apply it in layers if that feels easier.

Do I need to reapply sunscreen if I’m sitting in the shade?

Shade reduces UV exposure, but it doesn’t eliminate it, because UV reflects off surfaces such as sand, water and concrete. If you’re outdoors for long periods, still reapply and wear protective clothing.

Does sunscreen expire?

Yes. Check the expiry date, and avoid using sunscreen that has been stored in extreme heat, such as a hot car, as it may become less effective.

Can I use my sunscreen as moisturiser?

Some people do, but you’ll usually still want to apply a full, even layer to meet the SPF on the label.

Is a higher SPF better for the Australian summer?

A higher SPF can add a small amount of protection, but correct application matters more. Choose SPF 30 or higher and use enough.

The bottom line

The best sunscreen routine is the one you can keep up: about a teaspoon per body area, applied before you head out, reapplied every two hours, and combined with shade, clothing and a hat. If you’d like a formula you’ll enjoy reaching for, take a look at The Kind Collection or our FAQ for more about how we make it.