Spray foam insulation cost calculator
Spray foam is sold by the board-foot — one square foot sprayed one inch thick. Feed in your board-feet and the price your contractor quoted per board-foot and this figures the job, with room for overspray.
Calculator
1,000 board-feet at $1.20/bd-ft plus labor is about $1,320.00 with 10% contingency. Board-feet = area × thickness; enter your own $/bd-ft.
Formula
total = (board_feet × $/board-foot + labor − discount) × (1 + contingency)
Board-feet already carry the depth, so the price is per board-foot, not per square foot. If your quote is a flat $/ft² at a set depth instead, use the attic / wall cost tool.
Worked example
Say you are spraying 500 ft² of wall at 2 inches of closed-cell: that is 500 × 2 = 1,000 board-feet. At a quoted $1.20/board-foot, with labor bundled into the price and no discount, the subtotal is 1,000 × $1.20 = $1,200. Add a 10% contingency and the job lands at $1,320. Bump the price to $1.60/board-foot and the same job is about $1,760 — which is why the number you type here should come straight off your written quote, not a blog average.
What drives the price, from the field
Two jobs at the same square footage can be hundreds of dollars apart, and it is almost always one of these:
- Open- vs closed-cell. Closed-cell costs more per board-foot and needs fewer inches for a given R; open-cell is cheaper per board-foot but you spray more depth. Run both on the open- vs closed-cell compare before you price it.
- Depth. Board-feet scale straight with thickness. Going from 2" to 3" is 50% more board-feet and 50% more material cost, full stop.
- Access and prep. A tight crawl, a cut-up roofline, masking and removal of old insulation all add labor that a per-board-foot number can hide.
- Small-job minimums. Contractors carry a mobilization cost, so a tiny job rarely scales down linearly. For a rim joist or a spot fix, a DIY kit can pencil out better.
Measure first: get your area right (net of openings), decide the depth from the R you actually need, and only then price it. Guessing the depth is the most common way these estimates go wrong.
Reference table
| Foam | Typical installed $/ft² (labeled) |
|---|---|
| Open-cell spray foam | $1.00–$2.50/ft² |
| Closed-cell spray foam | $1.50–$4.50/ft² |
A labeled sanity band only — the depth and R you spray drive the real number. Enter your own quote above.
Frequently asked questions
How much does spray foam insulation cost?
It is priced by the board-foot (1 ft² at 1 inch). Open-cell installed runs roughly $1.00–2.50/ft² and closed-cell about $1.50–4.50/ft² at typical depths (labeled bands). Your real number depends on depth, access and local labor — enter the price off your own quote.
What is a board-foot of spray foam?
One board-foot is one square foot sprayed one inch thick. So 500 ft² at 2 inches is 1,000 board-feet. Depth is baked into the board-foot, which is why foam is priced that way instead of per square foot.
Should I include labor in the price?
If your quote is an all-in $/board-foot, leave the labor field at 0. If the contractor breaks out material and labor, put the labor total in its own field so the contingency applies to the whole job.
Is this a bid?
No. It is a planning estimate from your own numbers. Always get itemized written quotes from licensed, insured insulation contractors before you commit.