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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.

4200
440
28

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.

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.

Formula & Methodology

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

Number of Hoops = ⌈Length ÷ Hoop Spacing⌉ + 1

Arc Length = π × (Width ÷ 2)

Covering Area = Length × Arc Length

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

Number of Hoops = ⌈20 ÷ 4⌉ + 1 = 5 + 1 = 6 hoops

Arc Length = π × (12 ÷ 2) = π × 6 ≈ 18.85 ft

Covering Area = 20 × 18.85 ≈ 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

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.
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.
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.
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.
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.
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.
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.
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.
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