Calculating your displacement (cc) is straightforward once you know the Engine Displacement formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Engine Displacement Calculator.
What is Engine Displacement?
The Engine Displacement calculation tells you your displacement (cc) from a few simple inputs. The figure you are solving for here is the displacement (cc).
The Engine Displacement formula
The core formula is:
Displacement (cc) = 3.141592653589793 ÷ 4 × Bore ^ 2 × Stroke × Number of cylinders ÷ 1000Here is what each input means:
- Bore — a value measured in mm. Example: 84 mm.
- Stroke — a value measured in mm. Example: 90 mm.
- Number of cylinders — a number. Example: 4.
How to calculate it step by step
- Write down the bore (for example, 84 mm).
- Write down the stroke (for example, 90 mm).
- Write down the number of cylinders (for example, 4).
- Apply the formula above to get your displacement (cc).
- Double-check the result with the Engine Displacement Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Bore | 84 mm |
| Stroke | 90 mm |
| Number of cylinders | 4 |
| Displacement (cc) | 1,995 |
| Displacement (litres) | 2.00 |
With bore of 84 mm, stroke of 90 mm and number of cylinders of 4, the displacement (cc) works out to 1,995.
Example 2
With bore of 170 mm, stroke of 90 mm and number of cylinders of 4, the displacement (cc) works out to 8,171.
| Result | Value |
|---|---|
| Displacement (cc) | 8,171 |
| Displacement (litres) | 8.17 |
Example 3
With bore of 42 mm, stroke of 90 mm and number of cylinders of 4, the displacement (cc) works out to 499.
| Result | Value |
|---|---|
| Displacement (cc) | 499 |
| Displacement (litres) | 0.50 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Engine Displacement Calculator does it instantly, for free, with the formula and a worked example built in.
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