Hoop House Calculator — Greenhouse Tunnel Materials
Plan your hoop house build: enter the tunnel length, width, and hoop spacing to instantly get the number of hoops needed, the total pipe to buy, and the area of plastic sheeting or row cover required.
ft
ft
ft
Curved tunnel surface + both semicircular end walls
490.1 ft²
cover area- 1
Hoop radius
12 ÷ 2 = 6 - 2
Arc length per hoop
π × 6 = 18.8Semicircle: half the circumference of a full circle. - 3
Curved tunnel surface
18.8 × 20 = 377 - 4
Both end walls
π × 6² = 113.1 - 5
Total cover area
377 + 113.1 = 490.1
How does this calculator work?
Each semicircular hoop needs π × (width ÷ 2) feet of pipe. The number of hoops is ⌊length ÷ spacing⌋ + 1. Total plastic cover = (arc × length) + π × radius² for both end walls. Add 10–15 % overage when ordering materials.
Formula
How this is calculated
A hoop house is a low-cost tunnel greenhouse made from semicircular hoops (bent conduit or PVC pipe) covered with plastic film, greenhouse poly, or row-cover fabric. The width you enter is the internal floor span — the diameter of each hoop — so the radius is half that. Because each hoop traces a semicircle, the arc length of one hoop equals π × radius (half the full circumference of a circle with that diameter). Multiply by the number of hoops to get total pipe.
The plastic sheeting must cover the curved tunnel surface (arc length × tunnel length) plus two semicircular end walls (each with area π × radius² / 2). The calculator sums these for total cover area. Buy 10–15 % extra to allow for overlaps at the base and end-wall attachment.
Hoop spacing of 4 ft is typical for most crops; reduce to 2 ft in high-wind or snow-load regions. This calculator ignores ground anchoring hardware, door frames, and purlin pipes — factor those in separately when ordering materials.
Frequently asked questions
For a 12–16 ft wide structure, ¾" EMT electrical conduit or 1" schedule-40 PVC is common. Wider spans need ½" rebar ground stakes to anchor the pipe ends. Always check load ratings for your expected snow or wind loads — the math here sizes coverage, not structural capacity.
Use the 'Total plastic cover area' result and add 10–15 % for overlap at the base (you bury or anchor the edges) and at the end walls. Greenhouse poly is sold by the roll width — choose a width that equals or exceeds the arc length per hoop, so you have one continuous piece over the tunnel.
Yes — the math is the same regardless of height. A walk-in structure might be 12–20 ft wide (so the apex is 6–10 ft high), while a low tunnel over a garden bed might be 3–4 ft wide. Just enter your chosen width and the formulas handle the rest.
TG we-Calculate Editorial Team. (2026). Hoop House Calculator — Greenhouse Tunnel Materials [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hoop-house-calculator
TG we-Calculate Editorial Team. "Hoop House Calculator — Greenhouse Tunnel Materials." TG we-Calculate. 2026. https://we-calculate.com/calculator/hoop-house-calculator.
TG we-Calculate Editorial Team, "Hoop House Calculator — Greenhouse Tunnel Materials," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hoop-house-calculator
@misc{wecalculate_hoop_house_calculator, title = {Hoop House Calculator — Greenhouse Tunnel Materials}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hoop-house-calculator}}, year = {2026}, note = {TG we-Calculate} }
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