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Handlebar width calculator

Measure across your shoulders and you have the starting point for bar width. Fitting practice now sits just inside that number rather than on it.

Enter your shoulder width to see a starting range. Measure across your back from the bony tip of one shoulder (the acromion, the hard corner you can feel on top) to the other, with your arms relaxed.

Open Bike Fit

The full tool checks bar width against the bike you ride.

Why just inside your shoulders

The old rule was to match bar width to shoulder width. Riders have moved narrower since: most settle 5–10% inside their shoulders, and stock road bars have gone from about 44 cm to 40–42 cm. Narrower cuts frontal area and lets the arms sit more naturally on the hoods; too narrow and the chest closes up and the steering gets nervous, which is why the range stops at 90%.

Two ways of measuring a bar

Road bars are usually sold centre to centre at the hoods, but some brands quote outside to outside, which is about 25 mm more on the same bar. Flared gravel bars are wider at the drops than at the hoods, and the hood figure is the one that matters for fit. Check which number a bar is quoting before comparing it with anything.

If you race, there is a floor

From January 2026 the UCI requires road and cyclocross bars to be at least 400 mm outside to outside — roughly 375 mm centre to centre — with a maximum flare of 65 mm and at least 280 mm between the hoods. The calculator flags it when your starting width lands under that.

Where control beats aerodynamics

Gravel, bikepacking and anything loaded steers better with a wider bar, and flat-bar width is chosen for control and terrain rather than shoulder width at all. Width also changes how your shoulders and neck feel over hours, so treat a change as a trial rather than a purchase.

Check a whole bike, not one numberBike Fit takes your measurements and a geometry chart and gives the full starting setup — plus what to adjust.

Choosing a handlebar width

Handlebar width decides how open your chest sits, how much air you push, and how quickly the bike responds to your hands. The starting point is your shoulder width, measured acromion to acromion — the bony tips you can feel on top of each shoulder.

This calculator uses the same 90–105% band as the Bike Fit tool, with the best guess just inside shoulder width, and names the UCI racing minimum when the answer falls below it.

Frequently asked questions

How do I measure shoulder width for a handlebar?+

Measure across your back from the bony tip of one shoulder (the acromion) to the other, arms relaxed. That figure in millimetres is the reference for bar width measured centre to centre at the hoods.

Should handlebars be the same width as my shoulders?+

That was the old rule. Practice has moved inside it: most riders settle 5–10% narrower than their shoulders, and stock road bars have gone from about 44 cm to 40–42 cm. Gravel and control-first riders go the other way.

Is bar width measured centre to centre or outside to outside?+

Both are used. Centre to centre at the hoods is the common road convention; outside to outside is about 25 mm more on the same bar. The UCI measures outside to outside, which is why its 400 mm minimum is roughly 375 mm centre to centre.

What is the UCI handlebar width rule for 2026?+

From 1 January 2026, road and cyclocross bars must be at least 400 mm wide outside to outside, with a maximum flare of 65 mm and at least 280 mm between the hoods. It applies to racing under UCI rules, not to riding.

Do narrow bars make a bike harder to control?+

Narrower bars give less leverage, so the steering feels quicker and sprinting or loaded riding can feel less stable. The trade is a smaller frontal area and a more closed, aerodynamic position. Change one step at a time and ride it before deciding.

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