Enter four body measurements for a starting saddle height, stem length and bar reach — then add your current setup or a validation video below to see whether your fit is already dialed in.
Starting point, not a professional fit. These numbers come from published formulas using only 4 measurements — flexibility, riding style, injury history and your specific bike all matter too. Expect to fine-tune by a few mm up to ~2cm. If you have knee, back or hip pain, get a professional fit before making large changes.
Toggle on to enter the saddle height, setback, stem and crank length of the bike you actually have, for a fit assessment below.
Upload a short pedaling clip to check your knee angle, torso angle and saddle fore-aft at your current setup.
Toggle on to enter your frame's reach & stack from a geometry chart, to see your effective cockpit position with your current stem/spacers/bar.
Does it fit?
Fill in your measurements, then optionally add your current setup or a video, to see your fit assessment here.
How these were calculated
Saddle height uses the LeMond method (inseam × 0.883). Stem length scales with torso and arm length. Suggested bar reach scales with height and arm length — it describes a handlebar's own shape (the reach spec printed on a bar's box, typically 70-90mm), not your frame's reach measurement, so it isn't comparable to a geometry chart. All three are published starting-point formulas, not a measured fit. The "Does it fit?" panel above compares these formulas (and, if provided, a video reading of your current riding position) against your own current setup — it never invents a magnitude of adjustment, only a direction and a confidence level.
Bike Fit turns your inseam, torso length, arm length, and height into a saddle height, stem length, and suggested bar reach to start from — the LeMond method and the proportional formulas fitters have used for decades as a baseline before fine-tuning on the bike.
From there you can add your current setup (saddle height, setback, stem and crank length) and, optionally, a short video of yourself pedaling. The "Does it fit?" panel compares your current setup against the starting-point formulas and your video-measured riding position, and tells you — in plain language, with a stated confidence level — what might be worth adjusting. It never invents a distance to move something by, only a direction.
Everything runs in your browser and nothing is uploaded. Treat every number as a starting point: flexibility, riding style, injury history, and your specific frame all matter too.
No. These are published starting-point formulas and rule-based checks, not a measured, dynamic fit. A professional fitter accounts for flexibility, riding style, injury history, and pedalling mechanics that this tool cannot see. If you have knee, back, or hip pain, get a professional fit before making large changes.
For inseam, stand against a wall barefoot with a book pushed up snugly between your legs and measure floor to the top of the book. For torso, sit upright and measure from the sternum notch straight down to the seat. For arm length, measure from the point of your shoulder to the tip of your middle finger with the arm relaxed.
Saddle fore-aft position (the KOPS method) is not derived from body measurements in any of the standard formulas, so showing a personalized number would be misleading. It is shown as a general 0-20mm starting range instead, which many fitters now treat as a rough guideline rather than a rule.
No — both are optional. Enter as much or as little of your current setup as you know; the video is only used to validate your current riding position (knee angle, torso angle, and a rough saddle fore-aft read), never to estimate the setup numbers themselves, since a single video has no real-world scale to measure them with.
Saddle height (the LeMond method) is bike-agnostic — it only depends on leg length, so it applies the same way on any bike. Saddle setback (KOPS) applies to any seated pedalling position too. Stem length and suggested bar reach are scaled from a drop-bar (road-style) riding position, so on a flat-bar hybrid or mountain bike, treat them as a rougher proxy, not a target — select "Hybrid" or "Mountain bike" in the selector above the form to see this flagged inline. Crank length has no sourced target for any bike type; on a mountain bike it also affects pedal-strike clearance on technical terrain, which is a separate, real concern this tool still can't assess for you.
It is shown as a conflict at low confidence, not resolved by guessing which one is right. Two signals agreeing is what raises confidence — disagreement is shown honestly so you can judge it yourself, for example by re-checking a measurement or re-filming with a clearer side view.
No. Everything — the calculator, your current setup, and the video analysis — runs entirely in your browser. Nothing is sent to a server.