Engine Displacement Calculator
Calculate engine capacity from bore, stroke and cylinder count.
What the Engine Displacement Calculator does
Engine displacement is the total volume the pistons sweep in one full cycle. Each cylinder contributes the area of its bore multiplied by the stroke, and the bore-to-stroke ratio reveals whether the engine was designed to rev or to pull.
Formula
Volume per cylinder = π ÷ 4 × Bore² × StrokeDisplacement = Volume per cylinder × Cylinders1 cubic inch = 16.387 cc
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Cylinder bore | number | Yes | Accepts more than 0. |
| Stroke | number | Yes | Accepts more than 0. |
| Bore and stroke in | one of 2 options | Yes | — |
| Number of cylinders | number | Yes | Accepts 1 or more. |
How to use it
- Choose Bore and stroke in.
- Enter Cylinder bore, Stroke and Number of cylinders.
- Select Calculate.
Worked example
A four cylinder engine with an 86 mm bore and 86 mm stroke.
- Bore
- 86 mm
- Stroke
- 86 mm
- Cylinders
- 4
π ÷ 4 × 8.6² × 8.6 = 499.6 cc per cylinder, so 1,998 cc — a 2.0 litre engine, or 121.9 cubic inches.
Frequently asked questions
What does oversquare mean?
The bore is wider than the stroke is long. Piston speed stays lower at a given rpm, so the engine can rev higher — typical of sports and racing engines.
Why is a 1,998 cc engine called 2.0 litres?
Marketing rounding. Bore and stroke are chosen for engineering reasons and rarely land on a round displacement.