This engine displacement calculator works out your engine's total swept volume from bore, stroke, and cylinder count — in cubic inches (ci), cubic centimeters (cc), and liters (L). It's the starting point for any engine build, whether you're spec'ing a small-block Chevy, comparing crate motors, or converting a metric figure to American ci.
Engine Displacement Formula
Displacement is the total volume swept by all the pistons as they travel from bottom dead center (BDC) to top dead center (TDC). It's the single most important number describing engine size, because the more air-fuel mixture an engine can draw in per cycle, the more power it can potentially make. The formula multiplies the area of one cylinder (0.7854 × bore²) by the stroke length to get the volume of one cylinder, then by the cylinder count for the whole engine.
Bore vs Stroke: Why the Ratio Matters
Two engines can share the same displacement but behave very differently depending on their bore-to-stroke ratio. A big-bore, short-stroke "oversquare" engine revs higher and makes peak power at high RPM — typical of sports and racing engines. A long-stroke "undersquare" engine builds more low-end torque and is common in trucks and diesels. Increasing bore raises displacement with the square of the change, so boring a block oversize adds volume quickly; stroking the crank adds it linearly but also increases torque leverage.
Divide bore by stroke and the number tells you which camp an engine sits in:
| Bore ÷ stroke | Type | Character | Typical use |
|---|---|---|---|
| Above 1.0 | Oversquare | Revs freely, peak power high in the range | Sports and racing engines |
| About 1.0 | Square | Balanced compromise | General-purpose road engines |
| Below 1.0 | Undersquare | Strong low-end torque, lower rev ceiling | Diesels, trucks, marine |
The reason a short stroke revs is mean piston speed. A shorter stroke means the piston travels less distance per revolution, so piston speed stays lower at any given RPM — and piston speed, not RPM itself, is what ultimately limits safe engine speed. The wider bore also leaves room for larger valves, which helps the engine breathe high up. A long stroke does the opposite: it gives the connecting rod more leverage on the crankshaft, producing more torque low down at the cost of a lower rev ceiling.
| Engine | Bore × stroke | Ratio | Type |
|---|---|---|---|
| Chevrolet 350 small block | 4.00 × 3.48" | 1.15 | Oversquare |
| Ford 302 Windsor | 4.00 × 3.00" | 1.33 | Strongly oversquare |
| Chrysler 440 big block | 4.32 × 3.75" | 1.15 | Oversquare |
| Cummins 5.9 diesel | 4.02 × 4.72" | 0.85 | Undersquare |
Because displacement rises with the square of bore but only linearly with stroke, the arithmetic is lopsided: a 10% bore increase adds 21% displacement, while a 10% stroke increase adds exactly 10%. This is why small overbores go so far — a common 0.030" overbore on a 4.000" bore small block takes 349.8 ci to 355 ci, the famous "355", from thirty thousandths of an inch. The limit is cylinder wall thickness; bore too far and you break into the water jacket, which ends the block. Sonic testing before machining is standard on any block being taken near its limit.
Converting CI, CC, and Liters
Engine size is quoted in cubic inches in the US, and in cc or liters almost everywhere else. To convert: 1 cubic inch = 16.387 cc, and 1,000 cc = 1.0 liter. So a 350 ci engine is 5,735 cc, rounded to 5.7 L. Going the other way, a 2.0 L engine is 2,000 cc ÷ 16.387 ≈ 122 ci.
Common Engine Displacements
| Engine | Cubic Inches | Liters | CC |
|---|---|---|---|
| Chevy small-block 350 | 350 | 5.7 | 5,735 |
| Ford 302 (5.0) | 302 | 4.9 | 4,949 |
| Chevy LS 6.2 (LS3) | 376 | 6.2 | 6,162 |
| Chrysler 426 Hemi | 426 | 7.0 | 6,981 |
| Honda K20 | 122 | 2.0 | 1,998 |
Worked Example
This calculator provides estimates based on standard mathematical formulas. Real-world results will vary based on mechanical condition, environmental factors, and other variables.
If you are starting from a power goal rather than a bore and stroke, the HP to CC calculator estimates the displacement that target implies.
Frequently Asked Questions
Divide cubic inches by 61.02. For example, 350 ci ÷ 61.02 ≈ 5.7 Liters.
Divide cubic centimeters by 1000 for liters, or by 16.387 for cubic inches. A 1998 cc engine is about 2.0 L or 122 cubic inches.
Bore has a squared effect (it's the radius squared in the formula), so increasing bore raises displacement faster than the same increase in stroke.
A larger bore suits high-RPM power and bigger valves; a longer stroke builds low-end torque. Engine character depends on the bore-to-stroke ratio.
Displacement sets how much air and fuel the engine can move per cycle. More displacement generally means more potential power, though airflow and tuning decide how much is realized.