I made 121 calculators callable by AI agents (MCP) — and embeddable in any blog

Giuseppe Pio — Tue, 07 Jul 2026 15:22:27 +0000

Most calculator sites give you a number and hide the math. I wanted the
opposite: calculators you can trust, call from code, and drop into your own
pages. Here's how CalcFleet is put together and how you can embed one.

One function, three surfaces

Each calculator is a single tested pure function with a Zod schema. From that
one source it ships as:

a free web page (SSG),
a JSON REST API: POST /api/v1/tools/<slug>,
an MCP tool, so an AI agent can call the same math.

The AI never does the arithmetic — it only routes a plain-English question to
the right tool. ~2,300 tests back the formulas.

Embed one in your own post

Every tool has an "Embed this calculator" snippet. For example, a mortgage
overpayment calculator:

<iframe src="https://calcfleet.com/widget/mortgage-overpayment-calculator"
  width="100%" height="720" loading="lazy"
  style="border:1px solid #e4e0d6;border-radius:12px"></iframe>
<p style="font-size:14px">Calculator by
  <a href="https://calcfleet.com/mortgage/mortgage-overpayment-calculator">CalcFleet</a></p>

Let an agent call one (MCP, free)

The whole fleet is exposed as an MCP server, so an AI assistant can call any
calculator as a tool — same tested math, no arithmetic done by the model:

https://calcfleet.com/api/mcp

Point an MCP-compatible client at that endpoint and every calculator shows up
as a callable tool (the tool name is the slug with dashes as underscores).

For a plain REST API (metered, via RapidAPI) and full request/response
schemas, see https://calcfleet.com/developers. There's also an llms.txt at
the root that lists every tool for AI engines. The site's at
https://calcfleet.com — the web calculators are all free, no signup.

What calculator would you actually embed? I'll build the ones people ask for.

DEV Community: Giuseppe Pio

I made 121 calculators callable by AI agents (MCP) — and embeddable in any blog

One function, three surfaces

Embed one in your own post

Let an agent call one (MCP, free)