Pulsing Heart CSS animation

Based on various comments and making use of the ♥ we'll get this:

body {
  font-size: 40pt;
  color: red;
}
@keyframes heartbeat {
  0% {
    font-size: .75em;
  }
  20% {
    font-size: 1em;
  }
  40% {
    font-size: .75em;
  }
  60% {
    font-size: 1em;
  }
  80% {
    font-size: .75em;
  }
  100% {
    font-size: .75em;
  }
}
div {
  animation: heartbeat 1s infinite;
}
<div>
  &hearts;
</div>

You can incorporate the pause into the animation. Like so:

@keyframes heartbeat
{
  0%
  {
    transform: scale( .75 );
  }
  20%
  {
    transform: scale( 1 );
  }
  40%
  {
    transform: scale( .75 );
  }
  60%
  {
    transform: scale( 1 );
  }
  80%
  {
    transform: scale( .75 );
  }
  100%
  {
    transform: scale( .75 );
  }
}

Working example: https://jsfiddle.net/t7f97kf4/

@keyframes heartbeat
{
  0%
  {
    transform: scale( .75 );
  }
  20%
  {
    transform: scale( 1 );
  }
  40%
  {
    transform: scale( .75 );
  }
  60%
  {
    transform: scale( 1 );
  }
  80%
  {
    transform: scale( .75 );
  }
  100%
  {
    transform: scale( .75 );
  }
}

div
{
  background-color: red;
  width: 50px;
  height: 50px;
  animation: heartbeat 1s infinite;
}
<div>
Heart
</div>

Edit:

Working example with pure CSS heart shape: https://jsfiddle.net/qLfg2mrd/

@keyframes heartbeat
{
  0%
  {
    transform: scale( .75);
  }
  
  20%
  {
    transform: scale( 1);
  }
  
  40%
  {
    transform: scale( .75);
  }
  
  60%
  {
    transform: scale( 1);
  }
  80% {
    transform: scale( .75);
  }
  
  100%
  {
    transform: scale( .75);
  }
}

#heart
{
  position: relative;
  width: 100px;
  height: 90px;
  animation: heartbeat 1s infinite;
}

#heart:before,
#heart:after
{
  position: absolute;
  content: "";
  left: 50px;
  top: 0;
  width: 50px;
  height: 80px;
  background: red;
  -moz-border-radius: 50px 50px 0 0;
  border-radius: 50px 50px 0 0;
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -ms-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
  -webkit-transform-origin: 0 100%;
  -moz-transform-origin: 0 100%;
  -ms-transform-origin: 0 100%;
  -o-transform-origin: 0 100%;
  transform-origin: 0 100%;
}

#heart:after
{
  left: 0;
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
  -webkit-transform-origin: 100% 100%;
  -moz-transform-origin: 100% 100%;
  -ms-transform-origin: 100% 100%;
  -o-transform-origin: 100% 100%;
  transform-origin: 100% 100%;
}
<div id="heart"></div>

Pulse 2 times, take a small break, and then repeat it again

Try this. Going with animation opacity is a bad choice. transform: scale() will do the job. 

.heart:before {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  font-family: 'icons';
  font-size: 21px;
  text-indent: 0;
  font-variant: normal;
  line-height: 21px;
}
.heart {
  position: relative;
  width: 500px;
  overflow: inherit;
  margin: 50px auto;
  list-style: none;
  -webkit-animation: animateHeart 2.5s infinite;
  animation: animateHeart 2.5s infinite;
}
.heart:before,
.heart:after {
  position: absolute;
  content: '';
  top: 0;
  left: 50%;
  width: 120px;
    height: 200px;
    background: red;
    border-radius: 100px 100px 0 0;
  -webkit-transform: rotate(-45deg) translateZ(0);
  transform: rotate(-45deg) translateZ(0);
  -webkit-transform-origin: 0 100%;
  transform-origin: 0 100%;
}
.heart:after {
  left: 26%;
  -webkit-transform: rotate(45deg) translateZ(0);
  transform: rotate(45deg) translateZ(0);
  -webkit-transform-origin: 100% 100%;
  transform-origin: 100% 100%;
}
@-webkit-keyframes animateHeart {
  0% {
    -webkit-transform: scale(0.8);
  }
  5% {
    -webkit-transform: scale(0.9);
  }
  10% {
    -webkit-transform: scale(0.8);
  }
  15% {
    -webkit-transform: scale(1);
  }
  50% {
    -webkit-transform: scale(0.8);
  }
  100% {
    -webkit-transform: scale(0.8);
  }
}
@keyframes animateHeart {
  0% {
    transform: scale(0.8);
  }
  5% {
    transform: scale(0.9);
  }
  10% {
    transform: scale(0.8);
  }
  15% {
    transform: scale(1);
  }
  50% {
    transform: scale(0.8);
  }
  100% {
    transform: scale(0.8);
  }
}
span {
  font-family: 'Cantora One', sans-serif;
  font-size: 64px;
  position: absolute;
  top: 165px;
}
<div class="heart">
</div>

I like ketan's answer, but I wanted to improve the heart animation to make it more realistic.

  • A heart does not double in size when it beats. 10% change in size looks better to me.
  • I like it getting both larger and smaller
  • When it stops moving altogether it looks dead to me. Even when it isn't beating, it needs to expand or contract a little
  • I removed the "alternate directions" code so that it runs the same way through every time
  • I explicitly have the heart start end and at normal scale (1) and have the animation in the middle of the sequence. It seems clearer that way to me.

#heart img{
  position:absolute;
  left:0;
  right:0;
  margin:0 auto;
 }

 @keyframes heartFadeInOut {
  0% {transform: scale(1);}
  25% {transform: scale(.97);}
  35% {transform: scale(.9);}
  45% {transform: scale(1.1);}
  55% {transform: scale(.9);}
  65% {transform: scale(1.1);}
  75% {transform: scale(1.03);}
  100% {transform: scale(1);}
}

#heart img.bottom { 
  animation-name: heartFadeInOut; 
  animation-iteration-count: infinite;
  animation-duration: 2s;
}
<div id="heart" >
  <img class="bottom" src="https://i.stack.imgur.com/iBCpb.png" width="100px">
</div>

Tags:

Html

Css

Animation

Recent Posts