Answer: false. They are two measurements of one stroke, not two names for one thing. The casting arc is the angle change of the rod butt during the casting stroke. Stroke length is the distance the rod butt moves during that stroke.

One is angular and one is linear, so they do not have to rise and fall together. A stroke can sweep a wide angle while the butt barely travels, or carry the butt a long way through a narrow angle. The definitions give no rule tying the two numbers together.

Keeping them apart makes feedback precise. Ask for more arc and you are asking the caster to change the angle the butt sweeps through. Ask for a longer stroke and you are asking for more travel. Name the one you mean and the caster can change a single thing.

Both are measured only across the casting stroke, which the definitions describe as rotation and/or translation of the rod butt sufficient to cause loop formation. What happens either side of that stroke — pause, drift, drag, follow-through — is not part of either measurement.

Source

From the FFI Fly Casting Definitions (August 2025); terms follow the FFI Fly Casting Definitions; exam details are in the CI Study Guide (2025).