Print Size

{
  "asOf": "2026-10-11T08:40:15.829Z",
  "atDpi": {
    "100": {
      "heightCm": 101.6,
      "heightIn": 40,
      "widthCm": 152.4,
      "widthIn": 60
    },
    "150": {
      "heightCm": 67.73,
      "heightIn": 26.67,
      "widthCm": 101.6,
      "widthIn": 40
    },
    "200": {
      "heightCm": 50.8,
      "heightIn": 20,
      "widthCm": 76.2,
      "widthIn": 30
    },
    "300": {
      "heightCm": 33.87,
      "heightIn": 13.33,
      "widthCm": 50.8,
      "widthIn": 20
    }
  },
  "chosen": {
    "heightCm": 33.87,
    "heightIn": 13.33,
    "widthCm": 50.8,
    "widthIn": 20
  },
  "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.",
  "dpiUsed": 300,
  "megapixels": 24,
  "notChecked": [
    "print-shop requirements (bleed, colour profile, margins)",
    "sharpening, upsampling quality and the subject's detail",
    "…1 more"
  ],
  "reasons": [
    "Print size = pixels / dpi. 300 dpi is photo-quality at arm's length; 150 to 200 dpi suits larger prints seen from farther away.",
    "A print's minimum comfortable viewing distance is about 1.5 times its diagonal."
  ],
  "source": "computed locally",
  "suggestedViewingDistanceIn": 36.1,
  "summary": "6000 x 4000 px (24 MP) prints 20 x 13.33 in (50.8 x 33.87 cm) at 300 dpi; 30 x 20 in at 200 dpi.",
  "verdict": "COMPUTED"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://photo-calc.x402tookit.com/print-size?dpi=300&heightPx=4000&widthPx=6000'

# 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://photo-calc.x402tookit.com/print-size?dpi=300&heightPx=4000&widthPx=6000' \
  | 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%2Fphoto-calc.x402tookit.com%2Fprint-size
const res = await pay("https://photo-calc.x402tookit.com/print-size?dpi=300&heightPx=4000&widthPx=6000");
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://photo-calc.x402tookit.com/print-size?dpi=300&heightPx=4000&widthPx=6000")
    print(res.status_code, res.text)