Finance Utilities

Simple Interest

Calculate simple interest using the formula I = P × R × T. Available via MCP in Cursor, Claude, and other AI editors, or as REST API at /v1/finance/simple-interest. Pass principal amount, interest rate (as decimal), and time period to get exact interest calculations. Returns precise numerical results instead of approximated AI responses.

API Endpoint

GET /v1/finance/simple-interest

Code Examples

curl "https://tinyfn.io/v1/finance/simple-interest" \
  -H "X-API-Key: YOUR_API_KEY"

const response = await fetch('https://tinyfn.io/v1/finance/simple-interest', {
  headers: { 'X-API-Key': 'YOUR_API_KEY' }
});
const data = await response.json();
console.log(data);

import requests

response = requests.get('https://tinyfn.io/v1/finance/simple-interest',
    headers={'X-API-Key': 'YOUR_API_KEY'})
data = response.json()
print(data)

Use via MCP

Add to your AI agent

Connect your AI agent (Claude, Cursor, Windsurf, etc.) to TinyFn's finance tools:

{
  "mcpServers": {
    "tinyfn-finance": {
      "url": "https://tinyfn.io/mcp/finance",
      "headers": {
        "X-API-Key": "YOUR_API_KEY"
      }
    }
  }
}

Learn more about MCP setup →

Related Tools

FAQ

How do I calculate simple interest with TinyFn?

Use GET /v1/finance/simple-interest with parameters for principal, rate (as decimal like 0.05 for 5%), and time period. Returns the exact interest amount using I = P × R × T.

What format should the interest rate be in?

Pass the rate as a decimal: 0.05 for 5%, 0.125 for 12.5%. Don't use percentages like 5 or 12.5 as the calculation will be incorrect.

Can I use this tool in MCP-enabled AI editors?

Yes, it's available as an MCP tool in Cursor, Claude Code, GitHub Copilot, Windsurf, Cline, OpenClaw, and Zed for reliable financial calculations in your development workflow.

What's the difference between simple and compound interest?

Simple interest calculates interest only on the principal amount. Compound interest calculates interest on principal plus previously earned interest. This tool handles simple interest only.

Does the tool handle different time units?

The calculation uses whatever time unit you provide, but ensure your rate matches the time period (annual rate with years, monthly rate with months, etc.).

Try Simple Interest Now

Get your free API key and start using Simple Interest in seconds.

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