Engine Displacement Calculator

Written byOleh Soloninupdated 25 September 2026

Bore, mm

Stroke, mm

Cylinders

Combustion chamber, cc

Only needed for the compression ratio.

Result

Displacement, cc1,816.7
In litres1.82
Per cylinder, cc454.2
Bore to stroke ratio0.953
Engine charactersquare: an all-rounder
Compression ratioenter the chamber volume

Piston area times stroke, and that is all

Works out engine displacement from bore, stroke and cylinder count, and adds the compression ratio when the chamber volume is known.

Displacement is the piston's area times its stroke from top dead centre to bottom, times the number of cylinders. The area is π/4 × bore². That is where the "1.6" on the tailgate comes from, though the true figure is almost never round: 82 × 75.6 mm across four cylinders is 1,597 cc.

The ratio of bore to stroke describes the engine's geometry. A bore larger than the stroke makes it oversquare, a smaller one undersquare. The calculator calls anything between 0.95 and 1.05 "square" — its own boundary, not a standard.

How to use

Enter the bore and stroke in millimetres, from the engine's technical data.
Enter the number of cylinders.
If you know the combustion chamber volume of one cylinder, enter it to get the compression ratio.

Displacement from bore and stroke

Each row is a separate run of the calculator. The same capacity can come from different geometry, and the round litres in the brochure are a rounding.

Every row comes from the calculator on this page.
Bore × stroke	Cylinders	Displacement	Per cylinder	Bore/stroke
76.5 × 75.6 mm	4	1,389.9 cc	347.5 cc	1.012
82 × 75.6 mm	4	1,597 cc	399.2 cc	1.085
79 × 95.5 mm	4	1,872.4 cc	468.1 cc	0.827
86 × 86 mm	4	1,998.2 cc	499.6 cc	1
89 × 86 mm	6	3,210.1 cc	535 cc	1.035

What this calculator shows

Displacement in cubic centimetres and litres
The volume of one cylinder and the bore-to-stroke ratio
The compression ratio, if the chamber volume is known

What to keep in mind

The calculation is geometric: for an exact compression ratio, piston dishes and the gasket are measured separately and added to the chamber volume.
The 0.95 and 1.05 boundaries between undersquare, square and oversquare are the calculator's convention.

FAQs

How do I calculate engine displacement?

Multiply the cylinder area by the stroke and by the number of cylinders. The area is pi over four times the bore squared.

Why is the advertised capacity round and the calculated one not?

Because the name rounds it. An engine that calculates to 1,597 cc is sold as a 1.6; 1,998 cc becomes a 2.0.

What is compression ratio?

The full volume above the piston at bottom dead centre divided by the chamber volume at top dead centre: (swept volume + chamber) ÷ chamber. For 399.2 cc and a 40 cc chamber it is 10.98.

Oversquare or undersquare — what is the difference?

Geometry: oversquare means the bore exceeds the stroke, undersquare the reverse. For the same displacement per cylinder, the oversquare engine has the shorter stroke, so at the same revs its piston travels less — which is why such engines tolerate higher revs. The ratio alone does not fix the stroke.

How do I convert cc to litres?

Divide by 1,000: 1,597 cc is 1.597 litres, rounded to "1.6". The six-cylinder 3,210 cc engine is 3.21 litres.

Does displacement affect import charges?

Under the Russian personal-import rules, yes: for cars over three years old the single rate follows engine size, with separate rates for three to five years and over five, and steps at 1,000, 1,500, 1,800, 2,300 and 3,000 cc. The car import calculator applies them.

Worked example

A 1.6 from a mass-market saloon

Input: Bore 82 mm, stroke 75.6 mm, 4 cylinders, chamber 40 cc

Output: 1,597 cc, 399.2 cc per cylinder, compression 10.98

Note: A bore-to-stroke ratio of 1.085 — the calculator calls it oversquare. The compression ratio is (399.2 + 40) ÷ 40.

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