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HVAC Equipment Pad/Curb Footprint Calculator

Calculate the footprint area needed for an equipment pad or roof curb, including the manufacturer's required service clearance.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
3.94 ft2.95 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Required pad/curb footprint

19.38 ft²

High confidence

Use the specific equipment manufacturer's minimum service clearance requirements (often different on the service-access side vs. other sides) rather than a uniform assumed clearance — this calculator applies the single clearance value you supply evenly on all sides as a simplified estimate.

At the values currently entered, the required pad/curb footprint works out to 1.80 m². Figures are shown for United States, where IRC 2024 is the governing residential reference; switch the market above if you are building elsewhere.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Pad/curb footprint = (Equipment Width + 2 × Clearance) × (Equipment Length + 2 × Clearance), applying the manufacturer's required service clearance evenly around the equipment's footprint — a standard equipment placement sizing method.

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

How is the pad/curb footprint calculated?
Footprint = (Equipment Width + 2 × Clearance) × (Equipment Length + 2 × Clearance) — the required service clearance is added on both sides of each dimension before multiplying, applying the manufacturer's clearance evenly around the equipment's footprint.
Is a uniform clearance on all sides always correct?
No — this is a simplified estimate that applies the single clearance value you supply evenly on all four sides. Use the specific equipment manufacturer's minimum service clearance requirements, which are often different on the service-access side than on the other sides.
Should I use the unit's cabinet dimensions or its overall dimensions?
Use the equipment's overall width and length, including any base rails, piping stubs, or projections the manufacturer includes in its footprint dimensions, not just the bare cabinet size.