Stair Calc

{
  "angleDeg": 39.719,
  "asOf": "2026-10-11T14:25:13.933Z",
  "comfortRule": 25.429,
  "comfortRuleOk": false,
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "issues": [],
  "notChecked": [
    "your local code: limits below are the common US IRC residential ones (max riser 7-3/4 in, min tread 10 in, 3/8 in variation) and other places differ",
    "headroom (about 6 ft 8 in), handrails, guards, landings, nosing and stringer width and size",
    "…2 more"
  ],
  "reasons": [
    "Comfort rule 2 x riser + tread = 25.43 in (outside the 24 to 25 in range often used).",
    "Number of risers = total rise divided by the target riser, rounded; all risers are then equal.",
    "…1 more"
  ],
  "riserHeightIn": 7.71429,
  "risers": 14,
  "source": "computed locally",
  "stringerLengthIn": 169.009,
  "summary": "14 risers of 7.714 in and 13 treads of 10 in: total run 130 in (10.83 ft), stringer about 169.01 in, 39.7 degrees.",
  "totalRunFt": 10.833,
  "totalRunIn": 130,
  "treadDepthIn": 10,
  "treads": 13,
  "verdict": "WITHIN_COMMON_LIMITS"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://construction-calc.x402tookit.com/stair-calc?targetRiserIn=7.5&totalRiseIn=108&treadDepthIn=10'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://construction-calc.x402tookit.com/stair-calc?targetRiserIn=7.5&totalRiseIn=108&treadDepthIn=10' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fconstruction-calc.x402tookit.com%2Fstair-calc
const res = await pay("https://construction-calc.x402tookit.com/stair-calc?targetRiserIn=7.5&totalRiseIn=108&treadDepthIn=10");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://construction-calc.x402tookit.com/stair-calc?targetRiserIn=7.5&totalRiseIn=108&treadDepthIn=10")
    print(res.status_code, res.text)