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Free Health & Fitness Calculator Widgets

BMI, BMR, calorie, body-fat, macro, water-intake, pace and heart-rate-zone widgets for gyms, coaches and wellness blogs. Informational estimates, never a diagnosis.

Who these are for

Gyms, coaches, dietitians and wellness bloggers. Every widget is an informational estimate, not medical advice.

Common uses

  • A BMI or calorie estimate beside a nutrition article
  • Heart-rate zones and running pace on a training plan page
  • A due-date estimate on a pregnancy resource page

How embedding works

Pick a widget, set the theme and size, copy one line of HTML and paste it into your page. It runs in its own frame, so it cannot clash with your site's styles, and it resizes itself if you use the loader.

  • BMI Calculator

    Health & Fitness Calculator

    Body mass index with the WHO adult category and the healthy weight range for a height.

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  • BMR Calculator

    Health & Fitness Calculator

    Basal metabolic rate from Mifflin-St Jeor or the revised Harris-Benedict equation.

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  • Calorie Calculator

    Health & Fitness Calculator

    Maintenance calories (TDEE) and daily targets for gradual weight loss or gain.

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  • Body Fat Calculator

    Health & Fitness Calculator

    Body fat percentage from tape measurements with the US Navy method, plus ACE category.

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  • Ideal Weight Calculator

    Health & Fitness Calculator

    Devine, Robinson, Miller and Hamwi ideal weights side by side, with the healthy BMI range.

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  • Water Intake Calculator

    Health & Fitness Calculator

    An estimated daily fluid range from body weight and exercise time, from published guidance.

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  • Macro Calculator

    Health & Fitness Calculator

    Daily grams of protein, carbohydrate and fat from calories and a macro split.

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  • Pregnancy Due Date Calculator

    Health & Fitness Calculator

    Estimated due date, weeks pregnant, trimester and key dates from LMP, conception or IVF.

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  • Ovulation Calculator

    Health & Fitness Calculator

    Estimated ovulation day and fertile window for the next three cycles.

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  • Heart Rate Zone Calculator

    Health & Fitness Calculator

    Estimated max heart rate and five training zones, with optional Karvonen zones.

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  • Running Pace Calculator

    Health & Fitness Calculator

    Pace per km and per mile from distance and time, or finish time from a target pace.

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  • One Rep Max Calculator

    Health & Fitness Calculator

    Estimated 1RM from a set of 1-12 reps by Epley and Brzycki, with a training-load table.

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  • Class Timetable

    Health & Fitness Tool New

    A weekly gym or studio timetable with day tabs, class and level filters, Now and Next markers.

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How to add a widget

Open a widget, choose the theme, width and style, check the live preview, then copy the code. Paste it into an HTML or "Custom code" block on your site - step-by-step instructions for each platform.

Preview