Bike Size Calculator
Find the perfect bike frame size based on your height and inseam measurements
Calculate Your Bike Size
Your total height standing upright
Inside leg measurement from floor to crotch
Recommended Bike Size
Adult Bike Size Guide
Example Calculation
Road Bike Example
Height: 183 cm (6'0")
Estimated inseam: 86 cm
Formula: 86 × 0.67 = 57.6 cm
Frame size: 58 cm (23")
Size category: L (Large)
Mountain Bike Example
Height: 175 cm (5'9")
Estimated inseam: 82 cm
Formula: (82 × 0.67) - 11 = 44 cm
Frame size: 44 cm (17.5")
Size category: S (Small)
How to Measure Inseam
Stand Against Wall
Stand with feet 6-8" apart
Use a Book
Place hardcover book between legs
Mark & Measure
Mark spine position, measure to floor
Bike Type Guide
City/Trekking
Comfort, versatility, low maintenance. Perfect for commuting and recreational rides.
Road/Gravel
Speed and efficiency on paved roads. Lightweight with aerodynamic position.
Mountain
Off-road adventures and trails. Durable with wide tires and upright position.
Understanding Bike Sizing
Why Proper Bike Size Matters
A properly sized bike ensures comfort, efficiency, and safety. The right frame size allows for optimal power transfer, reduces fatigue, and prevents injury during rides.
Key Measurements
- •Frame Size: Distance from bottom bracket to seat tube top
- •Inseam: Inside leg measurement from floor to crotch
- •Reach: Distance from saddle to handlebars
- •Standover: Height clearance when straddling the bike
Sizing Formulas Explained
City/Trekking Bikes
Frame Size = Inseam × 0.64
Optimized for comfort and upright riding position
Road Bikes
Frame Size = Inseam × 0.67
Cyrille Guimard formula from the 1980s
Mountain Bikes
Frame Size = (Inseam × 0.67) - 11cm
Smaller for better maneuverability and control
Important Notes
- • Sizing can vary between manufacturers
- • Test riding is always recommended
- • Consider professional bike fitting for optimal comfort
- • Frame geometry affects handling and comfort