All converter widgets and converter apps are written in responsive html5 design and works for all operative systems and adapt to any device and size. Just copy and paste the code below to your webpage.
You can also create your custom design on your conversion calculator widget at Unit Converter Widget.
For testing purpose you can use the code below.
<div id="fw_138417302731871188"><a href="https://www.formloop.com/Unit-Converter-Widget">FormLoop Converter</a></div>
<script type="text/javascript" src="https://d15pwioa8qyjit.cloudfront.net/js/calc_quick_co.js"></script>
<script type="text/javascript">
var pass_id='138417302731871188';
var height='200';
var width='325';
var lang_code='';
var mobile='';
formloop_cw(pass_id,width,height,lang_code,mobile);
</script>
This will create a converter like the one to the left.You can choose which unit types to have in your conversion widget at Create conversion widget by clicking "Select Unit Types" button.