What you get
- Only the calculator. Fields and the result, nothing else. Tables and the explanation stay on our page, one click away for visitors who want them.
- Always current. Rates, formulas and fixes reach every copy of the widget the moment we publish them.
- Shows its work. Each calculator has a public page with the formula, a worked example and its sources, so you can check it before you put it in front of your readers.
- Nothing hidden. No ads, no pop-ups, no analytics counters inside the widget. One visible link under it is all we ask in return.
Frequently asked questions
Are the calculator widgets really free?
Yes. There is no sign-up, no plan and no limit on page views. The only thing we ask is that you keep the small Calcelate link under the widget.
How do I add a calculator to my website?
Pick a calculator above, choose the theme and units, copy the code and paste it into your page wherever HTML or embed code is allowed. It is an iframe plus one line of script that fits the height to the content.
Will the widget slow down my site?
It loads lazily, only when a visitor scrolls near it, and runs entirely in the visitor’s browser. There are no ads or analytics counters inside the widget.
Do the numbers stay up to date?
Yes. The widget always shows the current version of the calculator. When we correct a formula or update a rate, every copy of the widget updates without you changing anything.
Can I change the colors?
You can choose a light theme, a dark theme, or one that follows the visitor’s system setting. Calculators with a unit switch can be set to metric, imperial, or the visitor’s region.
What if my website builder removes the script line?
The widget still works. It just keeps the height set in the code, so change height="520" to a value that fits. Some hosted plans do not allow embed code at all; check your plan’s help pages for “embed HTML” or “custom code”.
Where do the formulas come from?
Every widget links to its full calculator page, which shows the formula, a worked example and the sources it is based on. Health calculators carry a medical disclaimer inside the widget as well.