# PennyRail Nano Percent Change Calculator

> PennyRail Nano Percent Change Calculator is a paid API for AI agents from pennyrail.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-22).

Computes the percent change (percentage change) between two numeric values

## Facts

- Endpoint: POST https://pennyrail.vercel.app/api/p/nano/number.percent-change--change-percentage?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pennyrail-nano-percent-change-calculator-cdf2fb66
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OXzVaZ56HtmQbRkzToPQW

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability pennyrail-nano-percent-change-calculator-cdf2fb66 -d '<json body>'
```

Example prompt: What is the percent change from 250 to 315? I need the percentage increase calculated.

## When to prefer this

Use this endpoint when you need a quick, machine-readable percent change computation without implementing the formula yourself. It is especially useful in automated pipelines where consistent formatting of percentage deltas is needed. Prefer this over a general-purpose math library call when you are already operating within the PennyRail x402 micropayment ecosystem and want a single consistent numeric transformation service.

## Known failure modes

- Missing or malformed input numbers causing a 400 error
- Division by zero if original value is zero
- Non-numeric input values returning a validation error
- Payment failure (402) if USDC balance is insufficient
- Service unavailability on the Vercel deployment returning 503

## How this service works

Machine-readable settlement service

## Output

Returns a computed percent change value representing the relative difference between an original and new number, expressed as a percentage (e.g. +12.5 or -8.3). The response is a JSON object with the calculated change percentage.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pennyrail-nano-percent-change-calculator-cdf2fb66/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pennyrail.vercel.app](https://www.zero.xyz/host/pennyrail.vercel.app/llms.txt)