Partially. Standard soda-lime window glass blocks most UVB and essentially all UVC—the wavelengths that sunburn you fast. It only knocks down about a quarter of UVA, so roughly three-quarters can still come through. You rarely pink up at a desk. You can still tan and age on the window side of your face.

The Skin Cancer Foundation walks through the same split: burn protection is not the same as UVA protection.

Glass type changes the answer

• Home windows (soda-lime): ~97% of UVB, ~25% of UVA.
• Tempered car side glass: similar UVB story; often only 60–71% of UVA.
• Laminated windshields: the plastic PVB interlayer does the heavy lifting—up to ~99% of UVA and UVB.
• Low-E coatings: commonly 85–95% of UV overall. Brown/amber tints block more than clear.

Those percentages are typical published ranges, not a reading for your particular pane. Age, film, and coatings move them.

Cars are uneven on purpose

You are well covered through the windshield and much less so through the driver’s window. That is why long commuters often show more damage on one side. Full write-up: do car windows block UV?

If you sit by glass for hours, treat a High UV day like outdoor time on the exposed side: clothing, and sunscreen if the skin sees sky. Window film is the usual retrofit when the glass itself will not change.