Engine Displacement Calculator
Bore, stroke and cylinder count into cubic inches, cubic centimetres and litres. Also shows what an overbore or a stroker crank gains you.
Engine dimensions
- Displacement is swept volume only. It does not include combustion chamber volume.
- Manufacturers round badly. A 350 Chevrolet is 349.8 ci, and a 5.7 litre is the same engine.
- Bore contributes as the square, stroke only linearly, which is why overboring gains more than it looks.
The formula
Displacement is the area of one cylinder multiplied by the stroke, multiplied by the number of cylinders. Because area depends on the square of the bore, a small increase in bore is worth more than the same increase in stroke.
That is why a 0.030 inch overbore on a V8 finds several cubic inches while barely changing anything else, and why it is the standard first move on a rebuild.
Bore to stroke ratio tells you the character
An oversquare engine has a bore larger than its stroke. Piston speed is lower at a given rpm, valves can be bigger, and the engine revs freely. Most modern performance engines are oversquare.
An undersquare or long stroke engine trades revs for leverage on the crank, which shows up as low end torque. Diesels and truck engines lean this way. Neither is better, they are tuned for different jobs.
Strokers add more than overbores
A longer crank throw adds displacement across the whole bore area at once, so a stroker kit typically gains far more than any safe overbore. The limits are piston to counterweight clearance, rod ratio, and how much the block will physically accept.
Frequently asked questions
How do I calculate engine displacement?
Multiply pi by the square of half the bore, then by the stroke, then by the number of cylinders. Work in centimetres to get cubic centimetres directly. A 4.00 by 3.48 inch V8 comes out at 5,733cc, or 349.8 cubic inches.
How much does a 0.030 overbore add?
On a 4.00 inch bore V8 with a 3.48 inch stroke, about 5.3 cubic inches, taking 349.8 to roughly 355. That is where the 355 small block name comes from. It is a modest gain, but the machining was going to happen anyway on a rebuild.
Is 5.7 litres the same as 350 cubic inches?
Effectively yes. 350 cubic inches is 5,735cc, which rounds to 5.7 litres. Manufacturers round aggressively and inconsistently, so the badge on the car is a marketing figure rather than a measurement.
Does more displacement always mean more power?
It means more air per revolution, which is the foundation of power, but heads, camshaft, induction and exhaust decide whether you use it. A well developed small engine routinely beats a poorly developed large one.
Everything on this page is an estimate worked out from the numbers you entered and typical figures for the conditions you picked. Your vehicle, your parts and your conditions will differ. Check anything you intend to act on against the manufacturer's specification, the service manual, or a qualified technician. Verifying the result before relying on it is up to you.