Gear table and gear range calculator
Build the full table of gear inches for every chainring and cog combination on your bike, with the total gear range and the combinations that duplicate each other.
—gear range
- Highest gear
- — in, on—
- Lowest gear
- — in, on—
—
Source for 700 × 28c (28-622): ETRTO 28-622 — the designation on the tyre sidewall. Every figure in the table is gear inches for that tyre, and an asterisk marks a combination another one duplicates.
What the table shows
Every box is one chainring against one cog, in gear inches: the diameter of the wheel a penny-farthing would need to go as far per pedal stroke. The highest gear sits top-left, the lowest bottom-right, because the chainrings are ordered largest first and the cogs smallest first.
Gear inches are used here rather than ratios because they are comparable between bicycles. A ratio of 4.5 means something different on a 650b gravel wheel than on a 700c road wheel; 121 gear inches means the same thing on both.
What gear range means
Gear range is the highest gear divided by the lowest, as a percentage. It is the single number that answers “how much spread does this drivetrain have” — and it is the number manufacturers print, so it is the one you can compare against a cassette on a shop page.
The convention is the multiple, not the increase over it. An 11–34 cassette is sold as a 309% range, and a 10–52 as 520%. A singlespeed is therefore 100%, not 0%: its highest gear is exactly its lowest. That is why this page asks for at least two cogs — one cog has a range by definition and nothing to show.
Range says nothing about the steps between gears. Two drivetrains with the same range can be spaced completely differently, and the table is where you see that.
Why some combinations are marked
A combination marked with an asterisk gives the same gear as another one in the table. On a double or a triple this is normal and unavoidable — the chainrings overlap, so some of the gears on the big ring repeat gears on the small one.
Two gears count as the same here when they differ by less than about 1.1%. That threshold is not arbitrary: at a given road speed, cadence is inversely proportional to gear size, so a 1.1% difference in gear asks for a cadence about one revolution per minute apart at a cadence of around 90 rpm, which is where most riders sit on the flat. Nobody can hold a cadence to within one rpm deliberately, so gears closer together than that are the same gear as far as your legs are concerned.
The marks are a floor, not a count. Gears are grouped against the first gear in each group, so a combination that sits just outside that one’s tolerance starts a group of its own — even when it is much closer to its neighbour than the threshold. On a triple you can see two gears marked as the same while a third, closer still to one of them, carries no mark at all. So a table with one mark may have more overlap than one mark’s worth; it will not have less.
What this does tell you is that you have fewer distinct gears than boxes, and roughly where the repeats are. A 2×11 drivetrain has 22 combinations and typically one or two fewer real gears than that — the example above has 21.
What the table does not tell you
It does not say which combinations you should ride. Cross-chaining — big ring to big cog, or small to small — is legal arithmetic and hard on the chain, and the table happily computes gears you would be better off reaching the other way. It also does not know what your derailleur can wrap, or what your frame will clear.
Those are compatibility questions and this site does not answer them. The manufacturers publish that information and it is authoritative; this page computes numbers.