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Hoop House Calculator

Construction

Calculate the number of hoops and square feet of plastic covering needed for a hoop house greenhouse. Enter length, width, and hoop spacing to plan your build.

Reviewed by the thecalcu.com team ยท Last updated July 6, 2026

4200
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Number of Hoops

6
Covering Area Needed
376.99

This calculator computes your Number of Hoops, Covering Area Needed from the values you enter.

Inputs
LengthWidth (Span)Hoop Spacing
Outputs
Number of HoopsCovering Area Needed

What is a Hoop House?

A Hoop House Calculator estimates two key material quantities for building a hoop house (high tunnel greenhouse): the number of curved hoop frames needed along the structure's length, and the total plastic covering area required to wrap over those hoops. Both figures come from your planned length, width (span), and hoop spacing.

Hoop houses are popular among gardeners and small-scale growers for extending the growing season affordably, but sizing the frame and covering correctly upfront avoids running short on plastic sheeting mid-build or under-bracing the structure against wind. If you're also planning the heating side of a covered growing space, the Heat Loss Calculator and Furnace Size Calculator cover related thermal planning.

Why Use a Hoop House Calculator?

Estimating plastic covering by eye often results in buying too little (requiring an awkward mid-project reorder) or too much (wasting material). This calculator converts your planned dimensions directly into a covering area estimate based on the curved geometry of the hoops, which is harder to eyeball than a flat rectangular calculation.

It also tells you how many hoops to buy or bend based on your chosen spacing, letting you quickly compare a tighter, stronger spacing against a wider, more economical one before committing to materials.

Who Should Use This Calculator?

Backyard gardeners use this calculator to plan a DIY hoop house for extending their growing season into fall and spring. Small-scale market farmers use it to budget plastic and conduit for multiple high tunnels across a growing operation. 4-H and school garden program organizers use it to plan educational hoop house builds with accurate material lists. Homesteaders use it alongside season-extension planning for raised beds and cold frames. Agricultural extension advisors reference it when helping growers estimate material costs for high tunnel proposals.

What Insights Does the Hoop House Calculator Give You?

The Number of Hoops result is the primary figure, it tells you how many curved frame pieces to bend or buy based on your chosen length and spacing. The Covering Area Needed result estimates the square footage of plastic sheeting required to span over the hoops along the full length of the structure, based on the curved arc created by your width input. Together these numbers form the core material list for a hoop house build, adjusting hoop spacing lets you trade off between a sturdier, more hoop-dense structure and a more economical, wider-spaced one.

How to use this Hoop House calculator

  1. Enter the Length of your hoop house in feet.
  2. Enter the Width (Span), the base width the hoops need to arch over.
  3. Enter your desired Hoop Spacing in feet (tighter spacing for more strength, wider for less material).
  4. Review the Number of Hoops result to know how many frame pieces to bend or buy.
  5. Review the Covering Area Needed result to estimate plastic sheeting to purchase, adding extra for end walls and ground securing.
Show formula & methodology โ†“Show less โ†‘

Formula & Methodology

The calculator estimates hoop count and covering area using the semicircular arc formed by the hoops:

Number of Hoops = โŒˆLength รท Hoop SpacingโŒ‰ + 1

Arc Length = ฯ€ ร— (Width รท 2)

Covering Area = Length ร— Arc Length

Worked example: For a 20 ft long, 12 ft wide hoop house with hoops spaced 4 ft apart:

Number of Hoops = โŒˆ20 รท 4โŒ‰ + 1 = 5 + 1 = 6 hoops

Arc Length = ฯ€ ร— (12 รท 2) = ฯ€ ร— 6 โ‰ˆ 18.85 ft

Covering Area = 20 ร— 18.85 โ‰ˆ 377 sq ft

Add extra material beyond this figure for end walls and for securing the plastic edges into ground trenches or a baseboard.

Frequently Asked Questions

What is a hoop house?
A hoop house, also called a high tunnel or polytunnel, is a simple greenhouse-style structure made from a series of curved (hooped) frames covered with plastic sheeting, used to extend the growing season by protecting plants from cold and wind. Unlike permanent greenhouses, hoop houses are typically unheated and rely on passive solar warming.
How far apart should hoop house hoops be spaced?
Hoop spacing typically ranges from 2 to 4 feet on-center, tighter spacing (2-3 ft) provides more structural strength for snow load or high-wind areas, while wider spacing (4 ft) reduces material and labor cost for milder climates. Check regional guidelines if you expect heavy snow loads.
How much plastic covering do I need for a hoop house?
Covering area depends on the arc length of your hoops (determined by the width/span) multiplied by the hoop house length, plus extra material for end walls and securing the edges into the ground. This calculator estimates the curved covering area based on your span and length inputs.
What width should a hoop house be?
Small backyard hoop houses commonly range from 10-14 feet wide, while commercial high tunnels can span 20-30 feet or more. Wider spans require taller, sturdier hoops and typically more bracing to resist wind and snow load.
Can I build a hoop house without special tools?
Yes, many hoop houses use bent metal conduit or PVC pipe for hoops, driven into ground stakes or a wood baseboard, making them accessible DIY projects that don't require specialized bending equipment for smaller spans. Larger commercial tunnels typically use purpose-built pipe benders for consistent hoop curvature.
What plastic thickness is best for hoop house covering?
6-mil greenhouse-grade polyethylene film is a common standard for hoop house covering, offering a reasonable balance of durability and light transmission, though 4-mil film is sometimes used for lighter-duty or seasonal applications. UV-stabilized film lasts longer under sun exposure than standard construction-grade plastic.
How does hoop spacing affect the number of hoops needed?
Tighter hoop spacing increases the total number of hoops needed for the same overall length, adding material cost but improving structural strength against wind and snow load, this calculator's Number of Hoops result updates automatically as you adjust the spacing input.
Does a hoop house need heating?
Most hoop houses are unheated and rely on passive solar gain and the insulating effect of the plastic covering to keep interior temperatures several degrees warmer than outside, though supplemental heating can be added for more aggressive season extension in cold climates.
How is a hoop house different from a traditional greenhouse?
Hoop houses are generally simpler, less expensive, and quicker to build than rigid-frame greenhouses, trading some structural permanence and climate control precision for lower upfront cost, making them popular for seasonal or small-scale growing operations.
Also known as
hoop house plastic calculatorgreenhouse hoop calculatorhigh tunnel calculatorhoop house covering estimatorpolytunnel material calculator