The Line Technique: How to Know You're Using Enough Sunscreen
TL;DR
- Draw a thick line of sunscreen down the center of each body part (like wrist to elbow for forearms) before rubbing it in
- When in doubt, always apply more—under-application is far more common than over-application
The Hack
Here's the problem: almost everyone under-applies sunscreen. Studies consistently show that people use 25-50% of the amount needed for the SPF rating on the bottle. That SPF 50 you're applying? You might only be getting SPF 15-25 protection.
The line technique solves this with a simple visual guide.
Instead of squeezing a blob of sunscreen into your palm and spreading it around, draw a thick line of product directly onto the body part you want to protect. For your forearm, that means a line from your wrist to your inner elbow. For your calf, a line from ankle to knee. For your face, lines across your forehead, down your nose, and across each cheek.
Once you've drawn your line, rub it in thoroughly. The pre-measured amount should spread evenly across the entire area with proper coverage.
Use this as your guide for each body part:
- Forearm: Wrist to inner elbow
- Upper arm: Elbow to shoulder
- Lower leg: Ankle to knee
- Upper leg: Knee to hip
- Torso: Multiple lines from shoulder to waist
- Face: Lines creating a cross pattern plus cheek stripes
If you finish rubbing and feel like you barely covered the area, your line wasn't thick enough. Add more and try again. With sunscreen, more is almost always better.
Why It Works
The line technique works because it takes the guesswork out of sunscreen application. When you squeeze product into your palm, you have no reliable way to gauge whether you have enough. The line gives you a physical measurement tied to the actual area you're covering.
Traditional guidance suggests using "a shot glass worth" for your whole body or "a nickel-sized amount" for your face. But these references are abstract. A line of sunscreen from your wrist to your elbow is concrete and repeatable.
This method also ensures even distribution. When you start with a line down the center of a body part, you naturally work the product outward to the edges. This prevents the common pattern of over-applying in the middle while leaving edges and sides with inadequate coverage.
The visual nature of the technique makes it easier to teach to kids and ensures consistency across multiple applications. Once you've calibrated what a proper line looks like for your arm, you'll apply the same amount every time.
Finally, this technique encourages generosity. When you see how much product it takes to draw a line the length of your forearm, you realize just how much sunscreen proper coverage requires. Most people are genuinely surprised.
Pro Tips
Practice with a new bottle. When you start a fresh sunscreen, pay attention to how quickly you go through it using the line technique. If a bottle lasts more than a month or two with daily use, you're probably still under-applying.
Adjust for body hair. Areas with more hair require additional product. The hair absorbs some sunscreen before it reaches your skin, so be more generous on arms, legs, and chest if applicable.
Use the two-finger rule for face. An alternative for facial application: squeeze two lines of sunscreen along your index and middle fingers. That amount should cover your face and neck adequately.
Don't skip the rub-in step. Drawing the line is just step one. Thorough rubbing ensures even coverage and helps the sunscreen absorb properly.
Reapply with the same technique. When it's time to reapply after two hours or swimming, use the line method again. Don't assume you need less just because you already have a base layer.
The "too much" feeling fades. When you first try this technique, you'll likely feel like you're using way too much sunscreen. Give it five minutes to absorb. That greasy feeling usually disappears as the product sets.
Key Takeaways
- Draw a thick line of sunscreen along each body part before rubbing in to ensure adequate coverage
- Most people apply 25-50% of the sunscreen needed for proper protection—the line technique corrects this
- When in doubt, add more sunscreen; under-application is the far more common problem
- Use this technique consistently for both initial application and reapplication throughout the day
