Formula
- 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.
- Equal paired upper/lower slopes with supplied horizontal runs. End walls, openings and material waste excluded.
Example Calculation
- Ridge length: 10 m
- Upper horizontal run each side: 2 m
- Upper slope: 30 °
- Lower horizontal run each side: 2 m
- Lower slope: 60 °
Ridge length = 10 m; Upper horizontal run each side = 2 m; Upper slope = 30 °; Lower horizontal run each side = 2 m; Lower slope = 60 °. Primary result: 126.188021535.
Frequently asked questions
How do I use this calculator?
Enter ridge length, upper horizontal run each side, upper slope, lower horizontal run each side, lower slope. The result updates automatically. Use Reset to restore the example values.
What method does it use?
area=2 ×length ×(upper run/cos upper angle+lower run/cos lower angle).. Equal paired upper/lower slopes with supplied horizontal runs. End walls, openings and material waste 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.