Skip to content
BEAD

Compound Interest Calculator

See how much an investment grows over time with compounding and optional regular contributions.

FinanceMath
Future value
$170,619.05
Total contributed
$70,000.00
Interest earned
$100,619.05
YearContributedInterestBalance
1$13,000.00$821.05$13,821.05
2$16,000.00$1,918.32$17,918.32
3$19,000.00$3,311.78$22,311.78
4$22,000.00$5,022.85$27,022.85
5$25,000.00$7,074.48$32,074.48
6$28,000.00$9,491.29$37,491.29
7$31,000.00$12,299.69$43,299.69
8$34,000.00$15,527.97$49,527.97
9$37,000.00$19,206.50$56,206.50
10$40,000.00$23,367.82$63,367.82
11$43,000.00$28,046.83$71,046.83
12$46,000.00$33,280.95$79,280.95
13$49,000.00$39,110.33$88,110.33
14$52,000.00$45,577.98$97,577.98
15$55,000.00$52,730.04$107,730.04
16$58,000.00$60,616.00$118,616.00
17$61,000.00$69,288.91$130,288.91
18$64,000.00$78,805.65$142,805.65
19$67,000.00$89,227.23$156,227.23
20$70,000.00$100,619.05$170,619.05
</>Use this tool programmaticallycurl · JavaScript · MCP

Same tool, callable from any HTTP client or from Claude (via MCP). Anonymous: 100 req/day per IP. Sign up for 1,000 req/day.

curl
curl https://api.b-e-a-d.com/tools/compound-interest/run \
  -H "Content-Type: application/json" \
  -d '{
  "principal": 10000,
  "annualRatePct": 7,
  "years": 10,
  "compounding": "monthly",
  "contribution": 0,
  "contributionFrequency": "monthly"
}'
JavaScript (fetch)
const res = await fetch("https://api.b-e-a-d.com/tools/compound-interest/run", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
  "principal": 10000,
  "annualRatePct": 7,
  "years": 10,
  "compounding": "monthly",
  "contribution": 0,
  "contributionFrequency": "monthly"
}),
});
const data = await res.json();
console.log(data.result);
MCP (Claude Desktop / Claude Code)
# In Claude Desktop / Claude Code, add to your MCP config:
{
  "mcpServers": {
    "bead": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.b-e-a-d.com"]
    }
  }
}

# Then ask Claude to call:
mcp__bead__bead_compound_interest

Full reference: developer docs · OpenAPI spec

How it's calculated

Starts from FV = P(1 + r/n)nt for a lump sum, then adds the future value of regular contributions. The annual chart breaks down each year into contributions, interest earned, and ending balance.

Compounding frequency matters less than you might think over long horizons — daily vs monthly compounding usually shifts the final number by under 1%. Time and rate do the heavy lifting.

You might also like