Knowing your greenhouse’s surface area comes in handy when you’re estimating heater size, comparing greenhouse designs, or getting a clearer picture of how much exterior surface is exposed to the outside.
Just choose your greenhouse style, enter your measurements, and click Calculate.
A few things to keep in mind
This calculator estimates the total exposed exterior area — roof and walls — not the floor footprint. It’s meant as a practical estimate, not an engineering specification.
If you run into trouble, the questions below should help. If you still need help, feel free to reach out by email or phone.
Q&As About the Greenhouse Surface Calculator
What does surface area mean here?
It’s the total exposed exterior area of your greenhouse — the roof and walls that face outdoor conditions. The floor isn’t included.
What can I use this calculator for?
It’s most useful for heater planning, comparing greenhouse shapes, and getting a sense of how much surface is exposed to outside temperatures.
Why is the surface area so much larger than my floor size?
Floor size only tells you how much ground space your greenhouse covers. Surface area adds in the roof and walls, which is why the number can be significantly larger than the footprint.
What is a Quonset greenhouse?
A Quonset greenhouse has a rounded, tunnel-style roof. It’s the shape most commonly used for hoop houses and other curved structures.
I have a gothic-arch greenhouse. Which style should I choose?
Use the Quonset option — it’s the closest match. Just keep in mind that gothic-arch greenhouses have a tighter, more pointed curve, so the calculator may slightly overestimate your surface area. Because gothic-arch and onion-shaped greenhouses don’t follow one standard curve, the Quonset option gives you the most practical reference point.
Why does the geodesic dome result include an approximation note?
Geodesic domes are made from many angled panels rather than a single continuous curve, which makes them harder to calculate precisely. The dome result is a curved-surface approximation rather than an exact panel-by-panel measurement.
Ready to size your heater?
Once you have your surface area, you can use it to estimate the BTU output your heater will need.