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Bike Size Calculator

Find your frame size from height or inseam, for road, hybrid and mountain bikes. Inseam is the more accurate anchor — height just gives a quick starting band.

Reviewed by the 247Sizing teamLast updated: 27 August 2026
Frame sizes are derived from the standard fit formulas (road = inseam × 0.70, hybrid × 0.685, mountain × 0.225 in inches). There's no universal chart — geometry varies by brand, so confirm standover clearance and the brand's own chart, and test-ride if you can.

Find your frame size

⚠️ A frame size is a starting point. Standover clearance (2-5 cm over the top tube), reach and saddle height all affect real fit — check the brand's geometry chart and test-ride before buying.

How to measure & choose

  1. Measure your inseam

    Stand barefoot, feet 15-20 cm apart, and measure from crotch to floor. More reliable than height for fit.

  2. Pick your bike type

    Road frames run largest, mountain smallest for the same rider — the calculator shows all three.

  3. Check standover

    You should clear the top tube by a few cm when standing flat-footed over the bike.

  4. Between sizes?

    Recreational riders size up for comfort; sportier riders size down for a racier reach.

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Bike Tape Measure / Fit Kit

Measure inseam and standover accurately before you buy a frame.

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Cycling Helmet

Don't ride without one — sized by head circumference.

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How these sizes are calculated

Bike frame sizes are derived from inseam using the standard fit multipliers (road x0.70, hybrid x0.685, mountain x0.225 in inches), with a height band as a quick starting point. Helmet and glove sizes map a body circumference to size bands. These are starting points — geometry and fit vary by brand, so confirm before buying, and for safety gear like helmets, never ride in one that doesn't fit.

Sources: Bike fit formulas & height/inseam charts (Cyclists Hub, RoadBikeRider, Icebike, 2026); Helmet head-circumference bands cross-checked (evo, multiple manufacturers, 2026); Glove hand-circumference sizing (standard S/M/L/XL bands).