Calculadora de Tamanho de Bike
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
speed = entreperna × 0,67 | MTB = entreperna × 0,57
About this calculator
This bike size calculator helps cyclists find the ideal frame size for road bikes (speed) and mountain bikes (MTB). The calculation is based on your inseam length, measured from the floor to your pubic bone. We multiply that value by 0.67 for road bikes and 0.57 for MTB, giving the recommended frame size in centimeters. The formula is widely used by shops and mechanics as a starting point for a basic fit.
Use this tool when buying a new bike or adjusting your current one. For example, when choosing between frame sizes 54 and 56, the calculator result indicates which one is closer to ideal. Remember that fine-tuning depends on other factors like saddle height, reach, and riding style. The calculator is an initial guide and does not replace a professional bike fit assessment.
Important precautions: measure your inseam accurately, preferably with someone's help. Use a tape measure and keep your feet shoulder-width apart. The result is approximate; manufacturers may have different geometries. For road bikes, size may vary by riding style (racing vs. leisure). For MTB, also consider suspension type and terrain. If between two sizes, choose the smaller for more agility or the larger for more comfort on long distances.
Frequently asked questions
How to measure inseam correctly?
Stand barefoot with feet shoulder-width apart. Measure from the floor to your pubic bone using a tape measure. Ask for help to ensure accuracy.
Why are the factors different for road and MTB?
Road bikes have a longer, more aggressive geometry, requiring a larger multiplier (0.67). MTB prioritizes maneuverability and impact absorption, with a smaller multiplier (0.57).
Is the calculator result definitive?
No. It is a starting point. Final adjustment depends on reach, saddle height, and personal preference. A professional bike fit is recommended.
What if I'm between two sizes?
For road bikes, choose the smaller for agility or the larger for comfort. For MTB, the smaller offers more technical control; the larger, stability on descents.
Does the calculator work for children's bikes?
Yes, but growing children may benefit from adjustable sizes. Also consider overall height and the manufacturer's recommended age.