CSS Animation Example: Circular Dash

The "Circular Dash" is an elegant loading spinner favored by Material Design frameworks, where a circular stroke stretches and contracts while rotating.

This animation is created by combining two separate @keyframes across two elements. First, the outer <svg> container revolves using a standard transform: rotate(). Second, the inner <circle> element's drawn line expands and contracts.

This expanding/contracting effect is achieved by animating two SVG-specific CSS properties: stroke-dasharray (which breaks the line into alternating dashes and gaps) and stroke-dashoffset (which dictates where the dash pattern starts drawing).

Here is the code to create the Circular Dash animation.

<!doctype html>
<title>Example</title>
<style>
body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: sans-serif;
    background-color: #f0f0f0;
}

.circular-loader {
    width: 60px;
    height: 60px;
    animation: rotate 2s linear infinite;
}

.circular-loader circle {
    stroke: #007bff;
    stroke-width: 4;
    stroke-dasharray: 1, 200;
    stroke-dashoffset: 0;
    stroke-linecap: round;
    fill: none;
    animation: dash 1.5s ease-in-out infinite;
}

@keyframes rotate {
    100% {
        transform: rotate(360deg);
    }
}

@keyframes dash {
    0% {
        stroke-dasharray: 1, 200;
        stroke-dashoffset: 0;
    }
    50% {
        stroke-dasharray: 89, 200;
        stroke-dashoffset: -35;
    }
    100% {
        stroke-dasharray: 89, 200;
        stroke-dashoffset: -124;
    }
}

@media (prefers-reduced-motion: reduce) {
    .circular-loader {
        /* Still rotate, but extremely slowly */
        animation-duration: 10s;
    }
    .circular-loader circle {
        /* Disable the rapid dash stretching */
        animation: none;
        stroke-dasharray: 60, 200; /* Create a static segment */
    }
}
</style>

View Output

Accessibility Considerations

As with many loading indicators, complete removal of the CSS animation when the prefers-reduced-motion media query detects a user's preference for minimal motion is ill-advised since it could look broken.

Instead, we halt the rapid expanding/contracting of the stroke-dasharray line, leaving a static visible segment, and significantly slow down the speed of the outer container's rotation, resulting in a gentle, non-distracting loading state.


@media (prefers-reduced-motion: reduce) {
    .circular-loader {
        /* Still rotate, but extremely slowly */
        animation-duration: 10s;
    }
    .circular-loader circle {
        /* Disable the rapid dash stretching */
        animation: none;
        stroke-dasharray: 60, 200; /* Create a static segment */
    }
}