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Free calculator widgets for your website

Put any of our 53 calculators on your own site: a due date calculator on a midwife’s blog, a loan calculator on a dealer’s page, a gestation calendar on a farm site. Pick one, set the look, copy the code. It is free, needs no account, carries no ads and updates itself whenever we improve the calculator.

1Choose and style

Theme
See the full calculator

Preview: how it looks on your site

2Copy the code for your platform

Add it to any website

  1. 1Copy the code.
  2. 2Paste it into the HTML of your page where the calculator should appear.
  3. 3Save and publish.

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.

All calculator widgets

Finance calculator widgets

  • Amortization calculator widget
  • Auto loan calculator widget
  • Dividend calculator widget
  • FIRE calculator widget
  • PayPal fee calculator widget
  • Prorated rent calculator widget
  • RMD calculator widget
  • RV loan calculator widget
  • Salary calculator widget
  • Scrap gold calculator widget
  • US inflation calculator (CPI) widget
  • Zakat calculator widget

Health calculator widgets

  • BAC calculator widget
  • Calorie deficit calculator widget
  • Due date calculator widget
  • FFMI calculator widget
  • Infant Tylenol dosage calculator widget
  • One-rep max calculator widget
  • Ovulation calculator widget
  • Pace calculator widget
  • Period calculator widget
  • Protein calculator widget
  • Sobriety calculator widget
  • TDEE calculator widget
  • Water intake calculator widget

Everyday calculator widgets

  • Age calculator widget
  • Bra size calculator widget
  • Date calculator widget
  • GPA calculator widget
  • Hours calculator widget
  • Ring size calculator widget
  • SAT score calculator widget
  • Time card calculator widget
  • Tire size calculator widget
  • Wheel offset calculator widget

Pets & livestock calculator widgets

  • Cat calorie calculator widget
  • Cow gestation calculator widget
  • Dog age calculator widget
  • Dog chocolate toxicity calculator widget
  • Goat gestation calculator widget
  • Horse gestation calculator widget
  • Raw dog food calculator widget

Construction calculator widgets

  • Asphalt calculator widget
  • Concrete calculator widget
  • Gravel calculator widget
  • Grout calculator widget
  • Mulch calculator widget
  • Pool volume calculator widget
  • Square footage calculator widget

Marketing calculator widgets

  • CPM calculator widget
  • YouTube money calculator widget

Generator widgets

  • Password generator widget
  • Random number generator widget