GARAGE CALCS FOR THE HOME BUILDER

Engine displacement calculator

Cubic inches, liters and cc from bore, stroke and cylinder count, with what common overbores do to it. Your numbers are saved to My Build so the carburetor and compression calculators can use them.

Free, no sign-upUpdated September 2026
Your numbers
Engine

Displacement

Total cc
Per cylinder
Bore / stroke ratio
Rod / stroke ratio
OverboreBoreCubic inchesLiters

How displacement is calculated

Cubic inches = 0.7854 × bore² × stroke × cylinders
cc = cubic inches × 16.387

0.7854 is π ÷ 4, which turns the bore diameter into the area of the cylinder. Multiply by the stroke for one cylinder's swept volume, then by the number of cylinders.

Overbore

The overbore table assumes the block is bored to the listed oversize and the stroke stays the same. Overbores are listed in the usual machine-shop steps. Whether a block can take them depends on cylinder wall thickness, which only a sonic check can tell you.

Bore/stroke and rod ratio

Bore/stroke above 1 is "oversquare", which generally favors higher rpm. Rod ratio (rod length ÷ stroke) affects how quickly the piston moves near top dead center and how hard it pushes the rod against the cylinder wall. Most production V8s sit roughly between 1.5 and 1.9.