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ADA Curb Ramp Detectable Warning Panel Calculator

Calculate the number of detectable warning (truncated dome) panels needed at the base of a curb ramp.

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
4.92 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Detectable warning panels needed

4 panels

Check your inputs

Confirm the exact detectable warning surface dimensions and panel product against ADA/PROWAG requirements and your local jurisdiction's standard detail — depth requirements can exceed the 24in ADA minimum in some jurisdictions.

Required warning surface area
9.85 ft²

For the dimensions entered, expect a detectable warning panels needed of 4. Note that required warning surface depth (m, ada minimum 0.61) sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Moderate confidence — sound arithmetic, but allow for the variation any real site introduces. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

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

  • Required warning surface area = ramp width × the ADA-required minimum depth (24 in / 0.61 m per ADA/PROWAG); panel count = ceil(required area ÷ single panel area)

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Frequently asked questions

Why is the minimum depth 0.61 m (24 in)?
ADA/PROWAG requires the detectable warning surface to extend a minimum of 24 in (0.61 m) in the direction of pedestrian travel at the base of a curb ramp, so it can be reliably detected underfoot or by cane before entering the roadway.
Can the required depth be more than the 0.61 m ADA minimum?
Yes — some jurisdictions specify a greater minimum depth in their own standard details. Always confirm the required depth against your local agency's standard drawing before finalizing panel quantities.
Does the panel count include waste for cutting at curves or edges?
No — this calculates the base panel count from the required rectangular warning surface area divided by a single panel's area, rounded up. Curved ramp edges, returns, or cut panels at odd geometries may require additional material beyond this count.