Engine Displacement Calculator
With bore 86 mm, stroke 86 mm, cylinders 4, engine displacement comes to 1,998 cc — displacement. It is reached in 5 steps, the last of which is 499.55721 * 4, and each one is printed on the page with its numbers filled in. The formula is the one published by NIST Handbook 44, Appendix C, not an approximation fitted to it.
Engine capacity from bore, stroke and cylinder count, in cubic centimeters, liters and cubic inches.
Formula and sources checked · How we check
Bore 86 mm, Stroke 86 mm, Cylinders 4
1,998 cc
Displacement for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Volume of one cylinder
pi * pow(86 / 2, 2) * 86 / 1000499.557 cc- Total displacement
499.55721 * 41,998.229 cc- In liters
1998.2289 / 10001.998 L- In cubic inches
1998.2289 / 16.387064121.939 cu in- Bore to stroke ratio
86 / 861
Worked example
An 86 mm bore and an 86 mm stroke over four cylinders is 1,998 cc — the two-liter engine, and a square one, since bore and stroke are equal. In American units it is 121.9 cubic inches.
How to work it out yourself
- 1.Measure or look up the bore, which is the cylinder diameter, and the stroke, which is the piston travel. Both are usually quoted in millimeters.
- 2.Halve the bore before squaring it. A cylinder volume uses the radius, and using the diameter multiplies the answer by four.
- 3.Multiply by the number of cylinders. Engines are advertised at a round figure — a "2.0 liter" is rarely exactly 2,000 cc.
The formula
- Volume of one cylinder
pi * pow(86 / 2, 2) * 86 / 1000 - Total displacement
499.55721 * 4 - In liters
1998.2289 / 1000 - In cubic inches
1998.2289 / 16.387064 - Bore to stroke ratio
86 / 86
Source: NIST Handbook 44, Appendix C — general tables of units of measurement
Questions people actually ask
- What does bore-to-stroke ratio tell you?
- How the engine prefers to make power. A ratio above one — a wide bore and a short stroke, "oversquare" — allows bigger valves and higher revs, which suits sports engines. Below one, "undersquare", gives more torque low down and less piston speed at a given rpm. Exactly one is called square, and the example above is one.
- Why is a 2.0 liter engine not 2,000 cc?
- Because the bore and stroke are chosen for the engineering and the badge is rounded afterwards. The 86 × 86 four above is 1,998 cc; plenty of "2.0" engines are 1,984 or 1,995. Tax and racing classes are written with that in mind, which is why an engine sits just under a class limit rather than on it.
- How do I convert cubic inches to liters?
- Multiply by 16.387064 for cubic centimeters, then divide by a thousand. A 350 cubic inch V8 is 5,735 cc — the "5.7 liter" on the badge. The factor is exact, since the inch is exactly 25.4 mm.
- Is this the same as swept volume?
- Yes — displacement is the swept volume of all the cylinders, the space the pistons move through. It excludes the combustion chamber above the piston at top dead centre, which is what the compression ratio describes instead. Total cylinder volume and displacement are not the same number.
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