Bike fit is the process of adjusting your bicycle's contact points — saddle, handlebars, and pedals — to match your body's dimensions and riding posture. A correct fit prevents knee, back, and neck pain, improves power transfer, and makes long rides dramatically more comfortable. This bike fit calculator converts your inseam, torso, and arm measurements into saddle height (three methods), reach, stack, handlebar width, and stem length recommendations for your riding style.
Your Measurements
Stand barefoot, measure from floor to crotch with book pressed up
Shoulder to waist (hip crease)
Shoulder to wrist (arm straight, palm down)
Bony tip to bony tip of shoulder (acromion to acromion)
Enter your measurements and click Calculate to see your bike fit recommendations
Saddle Height
Bottom bracket centre to saddle top
These are formula-based starting points. A professional bike fitter can refine further.
How to Use the Bike Fit Calculator
Getting your bike fit right is one of the highest-value things you can do as a cyclist. Even small errors — a saddle that is 10mm too low or bars that are 20mm too far — create discomfort on long rides and can cause overuse injuries over time. This bike fit calculator gives you evidence-based starting positions from your four key body measurements in minutes.
Step 1: Measure Your Inseam
Inseam is the most critical measurement for saddle height. Stand barefoot against a wall. Place a hardcover book between your legs, spine pressed firmly upward, simulating saddle contact. Have someone measure from the floor to the top of the book spine. Take two or three measurements and average them. Inseam in this calculator refers to your crotch-to-floor measurement without shoes. Toggle between cm and inches using the unit switch at the top of the page.
Step 2: Measure Torso and Arm Length
Torso length is the vertical distance from the centre of your hip crease (the fold where your leg meets your pelvis when you sit down) to the top of your shoulder. Arm length is the distance from the centre of your shoulder socket to your wrist bone, measured with your arm straight and palm facing down. These two measurements together determine your reach — how far forward you should lean — and appropriate stem length.
Step 3: Measure Shoulder Width
Shoulder width is measured from the bony tip of one shoulder (the acromion process — the point you can feel on top of your shoulder) to the other. This measurement drives handlebar width recommendations. Road cyclists typically use bars 0-4cm wider than this measurement; mountain bikers use much wider bars (720-800mm) for leverage and control.
Step 4: Set Flexibility and Style
Hip flexibility determines how aggressively you can rotate your pelvis forward without straining your lower back. Low flexibility (cannot touch toes) means you need a higher, more upright bar position. High flexibility allows a lower, more aero position. Your riding style further adjusts recommendations: a race position maximises aerodynamics but demands flexibility; a comfort position prioritises back and neck comfort for long days in the saddle.
Understanding the Results
The calculator shows saddle height from three methods: the LeMond formula (inseam × 0.883), the 109% method (inseam × 1.09), and the Holmes method range based on knee angle at bottom dead centre. It also shows recommended reach, stack, handlebar width, and stem length. These are starting points — fine-tune by riding for a few weeks and making small adjustments based on comfort and power feel. A professional bike fitter using video analysis is recommended for racers or anyone experiencing recurring pain.
Frequently Asked Questions
Is this bike fit calculator free?
Yes, completely free with no signup required. All calculations run locally in your browser and no personal data is ever sent to a server.
Is my data safe and private?
Yes, all calculations happen entirely in your browser. Your body measurements are never transmitted to any server or stored after you close the page.
What is the Lemond saddle height method?
Developed by three-time Tour de France winner Greg LeMond, this method multiplies your inseam length by 0.883 to get the saddle height measured from the centre of the bottom bracket to the top of the saddle. It is the most widely cited formula and works well for road cycling. The LeMond method assumes cleats add about 8-10mm to your effective leg length.
What saddle height method should I use?
The LeMond method (88.3% of inseam) is the most popular starting point for road riders. The 109% method (109% of inseam) is a common alternative that tends to give a slightly higher saddle position, preferred by some coaches. The Holmes method (25-35° knee angle at bottom dead centre) is the most biomechanically rigorous but requires a goniometer or video analysis. Use all three as a range and fine-tune from there by listening to your body.
How do I measure my inseam accurately?
Stand barefoot with your back against a wall, feet hip-width apart. Place a hardcover book between your legs with the spine pressed firmly upward against your crotch, simulating saddle pressure. Measure from the floor to the top of the book spine. Take two or three measurements and use the average. Inseam is the most important single measurement for saddle height.
What is reach and stack in bike fitting?
Stack is the vertical distance from the bottom bracket to the top of the head tube — it represents how high your handlebars can be positioned. Reach is the horizontal distance from the bottom bracket to the top of the head tube — it represents how far forward the bars are. Together they describe a frame's fit geometry. The calculator estimates the target reach and stack for your body, which you can then match to a bike's published geometry chart.
How wide should my handlebars be?
Handlebar width is primarily matched to shoulder width. For road cycling, bars are typically 2-4cm wider than your shoulder width to allow comfortable breathing and steering control. For aggressive race positions, some riders go shoulder-width or even narrower for aerodynamics. Mountain bike bars are much wider (720-800mm) for steering leverage on technical terrain.
Does riding style affect bike fit?
Yes significantly. A race position uses a longer reach, lower stack, and lower saddle-to-bar drop for aerodynamics — it requires good hip flexibility. An endurance position is slightly more upright with a shorter reach. A comfort or sportive position raises the bars further and shortens the reach more, reducing back and neck strain for long days in the saddle. This calculator adjusts all recommendations based on your selected riding style.
Should I see a professional bike fitter?
For most recreational cyclists, formula-based estimates provide a good starting point. For racers, cyclists with injuries, or anyone experiencing pain on the bike, a professional bike fit is strongly recommended. A fitter uses video analysis, pressure mapping, and dynamic observation to fine-tune saddle height, cleat position, handlebar reach, and saddle fore-aft position beyond what any formula can capture.