💠ROI Calculator
Calculate return on investment: profit (or loss) and the percentage return relative to the initial amount invested.
Worked examples
10,000 → 12,500
GET /api/v1/finance/roi-calculator?initial=10000&final=12500
Result: 25%
Losing trade: 5,000 → 4,200
GET /api/v1/finance/roi-calculator?initial=5000&final=4200
Result: -16%
House flip: 300,000 → 371,000
GET /api/v1/finance/roi-calculator?initial=300000&final=371000
Result: 23.67%
Machine API (x402)
$0.001 / callThis tool is also a JSON API for AI agents. Requests without payment receive 402 Payment Required plus instructions; agents pay USDC on Base via the x402 protocol — no accounts, no API keys.
GET /api/v1/finance/roi-calculator?initial=10000&final=12500 HTTP/1.1
Host: agenttools-hub.vercel.app
→ 402 (payment required, instructions in headers)
→ 200 (after X-PAYMENT header; JSON body below)
{
"tool": "finance/roi-calculator",
"input": {"initial":10000,"final":12500},
"result": { "value": 25, "answer": "25%" }
}Agent docs: /llms.txt · OpenAPI spec · integration guide
About this tool
ROI expresses an investment's profit as a percentage of what you put in — the simplest way to compare deals of different sizes. Negative results are losses; pair with CAGR to account for time.
ROI % = (final − initial) ÷ initial × 100
Frequently asked questions
Why is ROI misleading across different timeframes?
A 50% ROI in one year beats 50% over ten years, but ROI ignores time. Use the CAGR calculator to annualize returns before comparing.
Does ROI include fees?
Only if you subtract them yourself — use the net final value (after fees, taxes and costs) for an honest number.