Calendar difference

Calculate the precise difference between two datetimes in years, months, days, hours, minutes, seconds, and total milliseconds. Accepts ISO 8601, Unix timestamps, or natural date strings. ?from=2024-01-15&to=2026-06-23.

Input

Field	Type	Description
from *	string	Start datetime
to *	string	End datetime

Example output

{
  "from": "2024-01-15T00:00:00.000Z",
  "to": "2026-06-23T00:00:00.000Z",
  "diff": {
    "years": 2,
    "months": 5,
    "days": 8,
    "hours": 0,
    "minutes": 0,
    "seconds": 0
  },
  "total": {
    "days": 890,
    "hours": 21360,
    "minutes": 1281600,
    "seconds": 76896000,
    "milliseconds": 76896000000
  }
}

Try it — see the 402 challenge (free)

curl -i "https://agent402.tools/api/calendar-diff?from=2024-01-15&to=2026-06-23"

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

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

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/calendar-diff?from=2024-01-15&to=2026-06-23");

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits — a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=calendar-diff")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/calendar-diff", { method: "GET", headers: { "X-Pow-Solution": c.token + ":" + n } });

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