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For bloggers & site owners

Free calculator widgets for your website

Embed any of our 10 nutrition and fitness calculators with one line of code. Free forever, no signup, no API key — and they update themselves.

  • ✓ One line of HTML
  • ✓ Responsive & auto-resizing
  • ✓ Works on WordPress, Wix, Squarespace

BMI Calculator

Add a free BMI calculator to your website in one line of code.

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Calorie Calculator

Let your readers find their daily calories without leaving your page.

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Macro Calculator

Give readers a macro split they can actually use.

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Calorie Deficit Calculator

Show readers exactly what deficit hits their goal date.

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Calories Burned Calculator

MET-based burn estimates for any activity, embedded on your page.

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Body Fat Calculator

The U.S. Navy method, embedded free on your site.

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Ideal Weight Calculator

Healthy-range and classic-formula weights, on your page.

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Water Intake Calculator

A hydration target readers can calculate in two taps.

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Protein Intake Calculator

Evidence-based daily protein targets, embedded free.

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Intermittent Fasting Calculator

16:8, 18:6, 20:4 and OMAD windows, on your site.

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How it works

Pick a calculator, copy the one-line snippet from its page, and paste it into your post. The widget loads in a self-contained iframe, so it can't clash with your theme's CSS or slow the rest of the page down. A tiny script in the snippet lets it resize to fit its own content on mobile.

Licence

Free for any site, commercial or personal. Each widget keeps a small “Powered by LensNutra” credit — please leave it in place. That's the only condition.

Prefer to link?

Every calculator is also free to use and link to directly — see the full set of nutrition calculators, the food calorie database, or our sourced nutrition statistics if you need something citable.

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