Ever wondered which gear you should actually be in on a climb? Pick your weight, your power, your drivetrain and the hill. This tool runs the physics and hands you one clear answer: the exact gear that keeps your legs spinning at their happy cadence (how fast you turn the pedals).
How this works (the physics)
First we solve how fast your watts push you up that gradient: power fights gravity (weight × slope), rolling resistance, and air drag. Then we convert that speed into pedaling: each gear moves the bike a fixed distance per pedal stroke (chainring ÷ cog × wheel rollout). The recommended gear is the one whose distance-per-stroke matches your speed at the cadence you chose. Assumptions: relaxed road position, decent tires, calm air, sea level. Real roads vary, so treat the answer as your home base and shift one cog either way as the road talks to you.
