HesapHanem

Engine Displacement Calculator

Find your engine's total and per-cylinder displacement from bore, stroke, and cylinder count.

How it is calculated

The tool treats each cylinder as a short cylinder of diameter bore and length stroke. Both are entered in millimetres and converted to centimetres, so the volume of one cylinder is V1 = (π/4) × bore² × stroke in cubic centimetres. The engine total is V = V1 × cylinders, and litres are V / 1000. Total is shown as a whole number of cc, litres with two decimals and the per-cylinder figure with one decimal. The total is calculated from the unrounded per-cylinder volume, so multiplying the rounded per-cylinder number by the cylinder count can differ by a cc or two. Bore, stroke and cylinder count must all be above zero. It measures swept volume only, not the combustion chamber or compression ratio.

Worked example

A four-cylinder engine has an 86 mm bore and an 86 mm stroke. In centimetres these are 8.6 and 8.6. One cylinder: (π/4) × 8.6² × 8.6 = 0.7854 × 73.96 × 8.6 = 499.6 cc. Four cylinders: 499.56 × 4 = 1,998 cc in total. In litres, 1,998 / 1,000 gives 2.00 L, which is why this is sold as a 2.0 litre engine. Using the rounded 499.6 would give 1,998.4, so the unrounded value is what the tool multiplies.

Try this example →

Common mistakes

  • Entering bore and stroke in centimetres or inches. The fields are in millimetres, so 8.6 instead of 86 would make the result a thousand times too small.
  • Entering the piston radius or the cylinder wall thickness instead of the bore, which is the full cylinder diameter.
  • Using the connecting rod length or the crankshaft throw as the stroke. The stroke is the piston travel, which is twice the crank throw.
  • Entering cubic inches thinking the result will match, or comparing with a cubic-inch figure. Convert separately: the output here is cc and litres.
  • Expecting the marketing figure to match exactly. Makers round, for example 1,998 cc is sold as 2.0 L, so small differences are normal.

About this calculator

This calculator finds an engine's displacement — the total volume swept by all its pistons — using the cylinder volume formula V = π/4 × bore² × stroke × number of cylinders, reporting the result in cubic centimeters, liters, and per-cylinder volume.

Automotive enthusiasts and engine builders use it to compare or verify an engine's size from its bore and stroke specs, especially after a rebuild with different pistons, and it's a routine calculation in automotive engineering coursework. Bore and stroke are taken in millimeters, with the total reported in cubic centimeters and liters.

Was this helpful?

You can pick up to 3 reactions.

Comments (1)

  • Editorial team

    A handy use is predicting what a rebore does. Taking the guide's four-cylinder engine from an 86 mm to an 87 mm bore with the same stroke raises displacement from 1,998 cc to about 2,045 cc, roughly 2.3% more, because volume follows the square of the bore. Racing classes and tax rules often cap displacement, so check the margin before machining. What engine are you measuring?

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators