Calculator widgets

Any of these 260 calculators will run inside your page. Pick one, set the numbers it should open on, copy the iframe. It is the same widget that runs here, computing against the same evaluator.

It opens on your numbers

A page about 4-inch slabs should not open a concrete calculator on our 6-inch example. The builder writes your starting values into the URL.

No script, no tracking

One iframe. No JavaScript runs on your page, nothing is loaded from a third party, no cookie is set, and the widget cannot see your visitors.

Selling gravel, mulch or concrete?

There is a page written for supply yards rather than for developers: which calculator matches what you sell, what the coverage tables answer, and the three ways to use it. See /suppliers.

What it costs: one line of credit

The snippet includes a small grey line under the widget naming the calculator and linking back. That link is the whole price — there is no fee, no key and no sign-up. Delete the line if you would rather not, and the widget still works.

It stays correct

Formulas are tested on every build here, so a fix reaches every embed the moment it ships. You never update the snippet.

Terms, in full

Free, commercial use included, no attribution required beyond the link the widget already carries back to the calculator it came from. Leave that link in place and there is nothing else to agree to. We do not track your visitors and we will not start.

Finance

Health & Nutrition

Conversion & Math

Prefer to call it directly?

Every calculator is also a JSON endpoint and an MCP tool, so you can render the result in your own markup instead of an iframe. See the API and MCP documentation.