Engine Size Calculator
Enter the bore and stroke in millimetres and the number of cylinders. The calculator gives the engine size in cc, litres and cubic inches, the bore to stroke ratio and the mean piston speed at your chosen rpm.
- cc, litres and cubic inches
- Bore to stroke ratio
- Piston speed check
Bore and stroke are listed in workshop manuals and on most engine spec sheets.
Engine size is the volume all the pistons sweep. Each piston moves a cylinder of air equal to the bore area times the stroke. Multiply that by the number of cylinders and you have the displacement. A 2.0 litre engine sweeps 2,000 cubic centimetres every two crankshaft turns.
Well-known engines and their sizes
Real bore and stroke figures. Search by engine, size or layout.
| Engine | Layout | Bore × stroke (mm) | Displacement (cc) |
|---|---|---|---|
| Ford 1.0 EcoBoost | 3 cyl | 71.9 × 82.0 | 999 |
| VW 1.4 TSI | 4 cyl | 74.5 × 80.0 | 1395 |
| Honda K20 | 4 cyl | 86.0 × 86.0 | 1998 |
| Toyota 2GR | V6 | 94.0 × 83.0 | 3456 |
| Chevrolet LS3 | V8 | 103.25 × 92.0 | 6162 |
| Ford Coyote 5.0 | V8 | 92.2 × 92.7 | 4951 |
| BMW S58 | 6 cyl | 84.0 × 90.0 | 2993 |
| Honda CBR600RR | 4 cyl | 67.0 × 42.5 | 599 |
| Harley Milwaukee-Eight 107 | V-twin | 100.0 × 111.1 | 1746 |
| Suzuki Hayabusa | 4 cyl | 81.0 × 65.0 | 1340 |
Advertised sizes are rounded. Ford's 1.0 EcoBoost is actually 999 cc and Honda's K20 is 1,998 cc. Tax and insurance bands often use the exact figure.
Bore against displacement
A four-cylinder engine with an 86 mm stroke. Slide the bore to see the engine grow.
Boring an engine out by 1 mm on an 86 mm bore adds about 47 cc to a four cylinder. That is the classic way tuners gain capacity, limited by how thick the cylinder walls are.
How displacement is calculated
Three measurements and one formula. Step through the maths.
Measure the bore
The diameter of the cylinder. 86 mm is 8.6 cm.
The full formula is displacement = π ÷ 4 × bore² × stroke × cylinders. Work in centimetres to get cubic centimetres directly.
Oversquare, square or undersquare
The bore to stroke ratio shapes how an engine feels. Compare the three layouts.
Bore larger than stroke. Short stroke means lower piston speed, so the engine can rev higher.
Bore and stroke about equal. A balance of torque and revs.
Stroke longer than bore. More torque low down and often better efficiency.
Modern road engines are often close to square for a balance of power and efficiency. Motorcycle engines tend to be strongly oversquare to rev high.
Before you bore or stroke an engine
More capacity has knock-on effects. Run through these before any build.
Tick each item as you go.
Increasing displacement can move a vehicle into a different tax or insurance band, and in some countries it has to be declared to the registration authority.
What the calculator gives you
Five figures from three measurements. Each tile explains one result.
Total swept volume in cc and litres.
The US measure. 1 cubic inch is 16.387 cc.
Useful for comparing engines with different cylinder counts.
Shows whether the engine is oversquare or undersquare.
Average speed at your chosen rpm, in metres per second.
Mean piston speed is a quick health check. It is twice the stroke times rpm, and keeping it in a sensible range protects the bearings and rods.
Frequently Asked Questions
No question matches that search.
How do I calculate engine size?
Multiply π ÷ 4 by the bore squared, then by the stroke and the number of cylinders. With measurements in centimetres the answer is in cc.
How many cc is a 2.0 litre engine?
About 2,000 cc. 1 litre equals 1,000 cubic centimetres. Real engines are often a few cc either side.
How do I convert cc to cubic inches?
Divide by 16.387. A 5,700 cc engine is about 348 cubic inches.
Does a bigger engine mean more power?
Usually, but not always. Turbocharging, rpm and engine design matter as much. A modern 1.5 litre turbo can beat an older 2.5 litre.
What is a good bore to stroke ratio?
There is no single best ratio. Around 1.0 is common on road cars. Sports bikes run 1.5 or more to rev high.
What is a safe mean piston speed?
Most road engines stay under 20 m/s at the red line. Race engines can reach 25 m/s with special parts.
Does displacement include the combustion chamber?
No. Displacement is swept volume only. The chamber volume is used for working out compression ratio.
Know exactly what is under the bonnet
Use the bore and stroke from the manual and let the calculator do the maths. Check the bore to stroke ratio and piston speed too, so you understand how the engine delivers its power and how hard it is working.
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