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.
- Gaps remain fixed; surplus width is trimmed across the two edge pickets. Posts are excluded.
Example Calculation
- Clear panel width: 1800 mm
- Picket face width: 90 mm
- Desired internal gap: 10 mm
An 1800 mm opening with 90 mm pickets and 10 mm gaps requires 19 pickets and 90 mm total edge trimming.
Frequently asked questions
How do I use this calculator?
Enter clear panel width, picket face width, desired internal gap. The result updates automatically. Use Reset to restore the example values.
What method does it use?
n=ceil((panel width+gap)/(picket width+gap)); occupied width=n width+(n−1)gap.. Gaps remain fixed; surplus width is trimmed across the two edge pickets. Posts 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.