Paper Weight

{
  "asOf": "2026-10-12T01:48:14.938Z",
  "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.",
  "equivalentPoundsByType": {
    "bond": 21.3,
    "book": 54,
    "bristol": 36.5,
    "cover": 29.6,
    "index": 44.3,
    "tag": 49.2,
    "text": 54
  },
  "gramsPerSheet": 4.9896,
  "gsm": 80,
  "heightMm": 297,
  "notChecked": [
    "envelope, packaging and coating weight",
    "moisture content, which changes weight by a few percent",
    "…2 more"
  ],
  "ouncesPerSheet": 0.176,
  "reasons": [
    "Sheet weight = gsm x sheet area in square metres.",
    "US basis weights are for 500 sheets of the basic size of each paper type, so equal pounds are different gsm across types."
  ],
  "sheetAreaSquareMeters": 0.06237,
  "sheets": 500,
  "source": "computed locally (gsm x area; US basis-weight factors)",
  "stackGrams": 2494.8,
  "stackKilograms": 2.4948,
  "stackPounds": 5.5,
  "summary": "80 gsm: a 210 x 297 mm sheet weighs 4.99 g; 500 sheets weigh 2.495 kg (5.5 lb).",
  "verdict": "COMPUTED",
  "widthMm": 210
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://paper-print-calc.x402tookit.com/paper-weight?gsm=80&heightMm=297&sheets=500&widthMm=210'

# 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://paper-print-calc.x402tookit.com/paper-weight?gsm=80&heightMm=297&sheets=500&widthMm=210' \
  | 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%2Fpaper-print-calc.x402tookit.com%2Fpaper-weight
const res = await pay("https://paper-print-calc.x402tookit.com/paper-weight?gsm=80&heightMm=297&sheets=500&widthMm=210");
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://paper-print-calc.x402tookit.com/paper-weight?gsm=80&heightMm=297&sheets=500&widthMm=210")
    print(res.status_code, res.text)