What causes blisters when hiking?

Blisters are caused by friction between your foot and boot/sock. The main factors are: moisture (wet feet increase friction dramatically), poor-fitting boots, cotton socks, long distances, and new or unbroken-in boots. Prevention is far easier than treatment, so address these factors before your hike.

What are the best socks for preventing blisters?

Merino wool hiking socks are widely regarded as the best for blister prevention. They wick moisture, provide cushioning, and reduce friction. A liner sock underneath adds another friction-reducing layer. Never wear cotton socks for hiking — they hold moisture and guarantee blisters on long walks.

How should I treat a blister on trail?

If you feel a hotspot (red, warm area), stop immediately and apply blister tape or Compeed. If a blister has already formed, clean the area, apply a blister plaster, and tape over it. Do not pop small blisters. If a blister is large and causing pain, sterilise a needle, drain from the edge, apply antiseptic, and cover with a plaster.

How long does it take to break in hiking boots?

Most modern hiking boots need 50-100km of walking to break in properly. Start with short walks and gradually increase distance. Leather boots take longer (100-150km). Trail shoes typically need minimal break-in. If boots still cause hotspots after 100km of use, they may not be the right fit for your feet.

CampCalcs

Blister Prevention Calculator

Estimate blister risk and get prevention recommendations based on conditions.

Total Distance

Number of Days

Boot Break-in

Sock Type

Conditions

Blister History

How We Calculate This

Risk Score (0-100)

The risk score combines factors: daily distance (5-30 points), boot break-in (5-35), sock type (3-25), conditions (0-35), and blister history (0-20).

Tape Estimate

Based on the number of hotspot areas at risk (2-6 areas) multiplied by ~20cm per area per day of hiking.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.