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Free Embeddable Calculators
for Your Website

Add fully functional running pace calculators and heart rate zone calculators to your blog, coaching site, or fitness app. One line of code. No sign-up. No cost.

Lightweight

Under 5KB each. Zero external dependencies. Won't slow your site down.

Isolated

Shadow DOM encapsulation. No CSS conflicts with your existing styles.

Responsive

Works on mobile, tablet, and desktop. Adapts to any container width.

Easy Setup

Copy one line of code. Paste it anywhere on your page. Done.

Running Pace Calculator Widget

Let your readers calculate their running pace directly on your page. Enter distance and time to get pace per mile, pace per km, and speed. Perfect for running blogs, coaching sites, and race recap articles.

Embed Code

<script src="https://runbikecalc.com/widgets/pace-calculator-widget.js"></script>
Live Preview

Heart Rate Zone Calculator Widget

Give your audience an interactive heart rate zone calculator. Supports both the standard max HR method and Karvonen (heart rate reserve) method with optional resting HR input. Ideal for fitness sites, personal trainer blogs, and endurance coaching platforms.

Embed Code

<script src="https://runbikecalc.com/widgets/zone-calculator-widget.js"></script>
Live Preview

How to Add a Widget to Your Site

  1. Choose a widget from the options above.
  2. Copy the embed code by clicking the "Copy" button.
  3. Paste the code into your HTML where you want the calculator to appear.
  4. Publish your page — the widget loads automatically.

Works with WordPress, Squarespace, Wix, Ghost, Hugo, Next.js, and any platform that supports custom HTML. For WordPress, use a "Custom HTML" block in the editor.

Frequently Asked Questions

Are the widgets free?

Yes, 100% free. We only ask that you keep the "Powered by RunBikeCalc" attribution link visible.

Will this slow down my website?

No. Each widget is under 5KB of vanilla JavaScript with zero external dependencies. They load asynchronously and won't block your page rendering.

Will the widget conflict with my CSS?

No. Each widget uses Shadow DOM, which fully encapsulates its styles. Your site's CSS cannot leak in, and the widget's CSS cannot leak out.

Can I use multiple widgets on the same page?

Yes. Each widget creates a unique instance, so you can embed both the pace calculator and heart rate zone calculator on the same page without conflicts.

Do you track my visitors?

No. The widgets contain no tracking code, cookies, or analytics. They run entirely in the browser with no server calls.

Need a custom calculator widget for your site? Get in touch.

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