How this bed’s quantity is calculated
This example uses a 10 ft diameter circular bed with plastic · 20 ft roll. Its geometry is π × 10 = 31.416 ft (display rounded). The allowance is applied to the full-precision border length before any whole-unit rounding. Ten percent makes the buying target 34.558 ft. Each purchase unit provides 20 ft of nominal length; connectors, overlap losses, and special corner fittings are outside this nominal coverage calculation.
Buying target: 31.416 × 1.10 = 34.558 ft
Material count: ceil(34.558 ÷ 20) = 2 rolls
Purchased coverage: 2 × 20 = 40 ft
The purchase supplies 40 ft of nominal coverage. That is 8.584 ft more than the installed border, including both the selected allowance and whole-package rounding. This is a stock balance, not a measured disposal amount. Short offcuts may be reusable, and unopened stock may remain as a spare. Use the actual product label to confirm what length is available after any joints or overlaps.
Fixing assumptions for this example
The example fixing interval is two feet. The spike formula is max(3, ceil(31.416 ÷ 2)) = 16. This loop uses no extra endpoint spike. The result is 16 fixing spikes on the installed line. The waste allowance does not increase this count. Add any special joint, bend, or soil-related requirements from the product instructions separately; supplied hardware has not been deducted.
Adapt the estimate to your own border
Check whether you need the complete perimeter or only a portion of it. For a bed against a wall, use the measured-border mode to enter only the edge being installed. Choose a different allowance if your cut plan or spare-stock decision differs from this ten percent example. Do not infer product suitability, prices, or installation performance from these quantities.