ReusableForms v2.0 beta

Simple HTML age calculator from date of birth

Simple one liner to calculate age from date of birth
Sometimes you may need to calculate age from date of birth in a form. There are many uses for that: - calculate ticket rates when adults have higher rate - allow or disallow based on age In this form we use NittiJS and the calculateAge function from NittiJS to calculate age from date of birth.


        <div class="container mt-5">
    <div><label for="birth_date">Birth Date: </label>
      <input type="date" id="birth_date" name="birth_date" />
    <div id="age" style="padding-top:2em;">
      Age: <span r-calc="calculateAge(birth_date)"></span>

Integrating the Code with Your Web Page

To seamlessly integrate the form code from into your web page, follow these simple steps:

  • The form code is plain HTML. Click the copy button located above the code and paste it into your web page's source code.
  • If the form uses a CSS framework like Bootstrap or TailwindCSS, ensure that your web page or website project has the necessary libraries linked. Consult the respective library documentation for guidance.

Setting up Back-end Processing and Record Keeping

The form code provided above is for the client side only. To fully benefit from the form's features, you'll need a back-end form processor. Ratufa is one such service, and integrating with it is straightforward. Watch the video demo for a step-by-step example.

To receive email notifications upon form submissions, store submission records, and search through them later, you'll need a back-end processor. Here's how to set one up:

Using Ratufa Backend

  1. Go to
  2. Click the "Connect your form" button.
  3. Copy the provided code and paste it at the bottom of the HTML form code above
  4. You can test the form within ReusableForms before copying it to your website. will show submissions on the right side.
  5. Copy the combined code to your web page.
  6. Ratufa will store your form submissions, and you can configure email notifications. You can search and download records whenever needed.