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EasingClassic eases

easeOutBack

It starts fast and ends slowly. It passes its end value, then settles back.

easeOutBack reaches 50% of its travel at 13% of the time and 90% at 30%. Its peak speed is 4.7x the average. It passes the end value by up to 10%.

Classic easesfamily: backpeak 4.7x

Progress against time0100.51progress50%90%
The dashed line is linear. The dots mark 50% and 90% of the travel.
Velocity, in multiples of average speed01400.51speed, x average
The dashed line is 1x, the speed of linear.

Live demo

The blue box uses the exact linear() string below, in your browser. The grey box is linear.

easeOutBack
linear

Your system asks for reduced motion, so the boxes rest at the end of the move.

Numbers

50% of travel
13%of the time
90% of travel
30%of the time
After 10% of time
40.88%of the travel is done
Peak speed
4.7xtimes the average
Overshoot
10%past the end value
Undershoot
0%never below the start
linear() points
41at a 0.002 tolerance
cubic-bezier
exactworst gap 0.4 points

Copy the code

css linear() (exact)
animation-timing-function: linear(0, 0.1136, 0.2194, 0.3177, 0.4088, 0.4929, 0.5703, 0.6412, 0.7058, 0.7645, 0.8174, 0.8649, 0.9071, 0.9444, 0.977, 1.0051, 1.029, 1.049, 1.0653, 1.0781, 1.0877, 1.0944, 1.0984, 1.1, 1.0994, 1.0968, 1.0926, 1.087, 1.0802, 1.0725, 1.0641, 1.0554, 1.0465, 1.0376, 1.0292, 1.0213, 1.0143, 1.0084, 1.0039, 1.001, 1);
cubic-bezier (matches within 0.5%)
animation-timing-function: cubic-bezier(0.33, 1.57, 0.67, 1);

Least-squares fit to the easeOutBack curve; the worst gap is 0.4 points of travel. The linear() string is exact.

web animations api
el.animate({ translate: ['0 0', '240px 0'] }, { duration: 600, easing: 'cubic-bezier(0.33, 1.57, 0.67, 1)', fill: 'both' });
vawe
import { easeOutBack } from '../../core/motion/curves.js';
import { curveToLinear } from '../../core/motion/springs.js';

const easing = curveToLinear(easeOutBack, { tolerance: 0.002 }); // the linear() string above
const x = easeOutBack(u);                                         // per-frame code, u in 0..1

When to use it, and when to avoid it

Use it for

  • A card or badge that arrives and overshoots its place, then settles.
  • Playful UI: toggles, chips and toasts.

Avoid it for

  • Text blocks and tables: the overshoot reads as a layout error.
  • Opacity: a value above 1 is clamped, so the overshoot does nothing. Use pop on scale.

The nearest vawe ease

The closest of the nine vawe After Effects eases is pop, an RMS gap of 0.099 in progress. After Effects and vawe set the shape with two handles, so it can be tuned where a named curve cannot.