Formula
r=width/2; curved cover=πrL; two ends=πr².
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Exact semicircular cross-section, no straight sidewalls. Doors, overlaps and fixing allowances are excluded.
Example Calculation
Example inputs
- Width: 4 m
- Length: 10 m
A 4 m wide, 10 m long semicylinder has curved cover area 20π m².
Frequently asked questions
How do I use this calculator?
Enter width, length. The result updates automatically. Use Reset to restore the example values.
What method does it use?
r=width/2; curved cover=πrL; two ends=πr².. Exact semicircular cross-section, no straight sidewalls. Doors, overlaps and fixing allowances are excluded.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.