Construction Calculator API

v1.0.0 · 65 calculators · imperial & metric · JSON

Contractor-grade material take-offs and planning costs, from the same tested formulas that run the Smart Calculator sites (smartroofingcalculator.com, smartdeckingcalculator.com, smartfencingcalculator.com, smarttilecalculator.com, smartgravelcalculator.com).

Access is through RapidAPI: subscribe there, then call the RapidAPI host with your key. Direct calls to this origin are refused.

What you can build

• Contractor quote forms: turn a homeowner's measurements into a material list and a price range before the site visit.
• Estimating and CRM tools: add roofing squares, shingle bundles, deck boards, fence posts or drywall sheets to a job record in one call.
• Home-improvement apps and stores: show "you need 74 bundles" next to the product, in imperial or metric.
• Spreadsheets and no-code: call it from Google Sheets (Apps Script), Zapier or Make with a plain GET request.

Quick start

Use the host shown on the RapidAPI listing; the one below is illustrative.

curl --get https://construction-calculator-api.p.rapidapi.com/v1/roofing/shingles \
  -H "X-RapidAPI-Key: $RAPIDAPI_KEY" \
  -H "X-RapidAPI-Host: construction-calculator-api.p.rapidapi.com" \
  -d length=50 -d width=40 -d pitch=6 -d wastePercent=10

{ "endpoint": "/v1/roofing/shingles", "units": "imperial",
  "result": { "roofArea": 2236.068, "squares": 24.5967, "bundles": 74, … },
  "units_of_measure": { "roofArea": "sq ft", "bundles": "count", … },
  "notes": ["Average residential roof size."], "warnings": [], "requestId": "…" }

// JavaScript (Node 18+ or the browser, through your own backend so the key stays private)
const r = await fetch("https://construction-calculator-api.p.rapidapi.com/v1/fencing/posts?length=150&postSpacing=8&gates=1", {
  headers: { "X-RapidAPI-Key": process.env.RAPIDAPI_KEY, "X-RapidAPI-Host": "construction-calculator-api.p.rapidapi.com" },
});
const { result } = await r.json();

# Python
import os, requests
r = requests.get("https://construction-calculator-api.p.rapidapi.com/v1/drywall/room",
    params={"length": 12, "width": 12, "height": 8},
    headers={"X-RapidAPI-Key": os.environ["RAPIDAPI_KEY"], "X-RapidAPI-Host": "construction-calculator-api.p.rapidapi.com"})
print(r.json()["result"])

Every endpoint takes GET query parameters or a POST JSON body. Add units=metric to send and receive m, mm, m², m³, kg, t and L. Counts (bundles, sheets, bags) and money are never converted.

Errors

{ "error": { "status": 400, "code": "INVALID_PARAMETER",
    "message": "'length' must be greater than 0 ft",
    "details": [{ "param": "length", "issue": "must be greater than 0 ft" }] },
  "requestId": "…" }

Codes: INVALID_PARAMETER, MISSING_PARAMETER, INVALID_JSON, PAYLOAD_TOO_LARGE (400/413) · UNAUTHORIZED (401) · NOT_FOUND (404) · METHOD_NOT_ALLOWED (405) · RATE_LIMITED (429) · INTERNAL_ERROR (500).

Endpoints

Roofing 22

Decking 9

Fencing 9

Drywall 4

Insulation 3

Tile 5

Landscape & Aggregates 6

Concrete 2

Paint 1

Conversions 4

Try it free on RapidAPI

Planning estimates, not engineering. © Dixon App Studio · Try the formulas by hand: roofing, decking, fencing, tile, gravel · developer page