Beginner roller skating
How to Size Roller Skates (Don't Guess Your Shoe Size)

Most beginner pain comes from a bad fit, not from falling. Measure in millimetres, check the brand's own chart, size snug - never loose.
Most beginner pain comes from a bad fit, not from falling. Blisters, numb toes and heel lift are all sizing problems wearing a disguise.
Measure your foot in millimetres, heel to longest toe, standing, at the end of the day when your feet are at their largest. Then read the brand's own chart — skate sizing is not shoe sizing and it varies wildly between makers.
Aim for snug: toes brushing the end, zero heel lift when you rise onto the ball of your foot. A skate you can wiggle in is a skate you cannot steer.
Where to start looking: Impala is the quad most beginners in this corner of skating end up on, which makes it one of the easier brands to find a size chart for. Check your measured size against what is actually in stock before you fall for a colourway — the common sizes sell out first, and the wrong size in the right print is still the wrong size. See the Impala quad skates. That is an affiliate link: if you buy through it this site earns a commission, at no extra cost to you.
Keep going: this is one section of the full Roller Skating for Beginners guide — sizing, gear, stopping, and where to skate, in one page.