Generated by SassMeister.com.

SassMeister Progress Circle.html

<div class="progress-button loading">
  <button></button>
  <svg class="progress-circle" width="300" height="300">
    <path d="M149.5,5C229.3,5,294,69.7,294,149.5S229.3,294,149.5,294S5,229.3,5,149.5S69.7,5,149.5,5z"></path>
  </svg>
</div>

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

.progress-button {
    position: relative;
    display: inline-block;
    text-align: center;
    min-width: 250px;
    margin: 10px;
    background-color: #eee;
    button {
      width: 300px;
      height: 300px;
      border: 2px solid #1ecd97;
      border-width: 10px;
      border-color: #fff;
      border-radius: 50%;
      display: block;
      margin: 0 auto;
      padding: 0;
      background: transparent;
      
    }
    .progress-circle {
      position: absolute;
      background-color: transparent;
      top: 0;
      left: 50%;
      -webkit-transform: translateX(-50%);
      transform: translateX(-50%);
      pointer-events: none;
      path {
        stroke-dasharray: 908px;
        stroke-dashoffset: 500px;
        opacity: 1;
        -webkit-transition: stroke-dashoffset 0.3s;
        transition: stroke-dashoffset 0.3s;
        stroke: #1ECD97;
        stroke-width: 10;
        fill: none;
      }
    }
}

SassMeister-output.css

.progress-button {
  position: relative;
  display: inline-block;
  text-align: center;
  min-width: 250px;
  margin: 10px;
  background-color: #eee;
}

.progress-button button {
  width: 300px;
  height: 300px;
  border: 2px solid #1ecd97;
  border-width: 10px;
  border-color: #fff;
  border-radius: 50%;
  display: block;
  margin: 0 auto;
  padding: 0;
  background: transparent;
}

.progress-button .progress-circle {
  position: absolute;
  background-color: transparent;
  top: 0;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  pointer-events: none;
}

.progress-button .progress-circle path {
  stroke-dasharray: 908px;
  stroke-dashoffset: 500px;
  opacity: 1;
  -webkit-transition: stroke-dashoffset 0.3s;
  transition: stroke-dashoffset 0.3s;
  stroke: #1ECD97;
  stroke-width: 10;
  fill: none;
}

SassMeister-rendered.html

<div class="progress-button loading">
  <button></button>
  <svg class="progress-circle" width="300" height="300">
    <path d="M149.5,5C229.3,5,294,69.7,294,149.5S229.3,294,149.5,294S5,229.3,5,149.5S69.7,5,149.5,5z"></path>
  </svg>
</div>