Cubic-Bezier Generator: Master CSS Easing Curves

Animation is what separates an interface that feels alive from one that feels like a slideshow. And the single most important ingredient in good animation is not duration or distance — it is the easing curve. Easing describes how a value accelerates and decelerates over time. Linear motion looks robotic; well-eased motion feels physical, intentional, and human. In CSS, the most powerful way to express easing is the cubic-bezier() function, and the fastest way to author one is with a visual cubic bezier generator — a CSS easing editor that lets you drag two control handles and watch the curve update in real time.

What Is a Cubic Bezier Curve?

A cubic Bezier easing curve is defined by four numbers: cubic-bezier(x1, y1, x2, y2). The curve always starts at the point (0, 0) and ends at (1, 1). The horizontal axis represents time, progressing from the start of the animation to the end. The vertical axis represents progress — how far along the animated value is. The two pairs of coordinates are the two control points that bend the line between start and finish.

The x values are constrained between 0 and 1 because you cannot move backward or forward in time. The yvalues, however, can go below 0 or above 1. That is what produces those delightful overshoot and anticipation effects, where an element springs slightly past its target before settling — the basis of every "bouncy" or "back" easing you have seen.

The Built-in CSS Keywords Are Just Beziers

Every easing keyword you already know maps to a specific cubic-bezier value:

• ease = cubic-bezier(0.25, 0.1, 0.25, 1) — the browser default
• linear = cubic-bezier(0, 0, 1, 1) — constant speed
• ease-in = cubic-bezier(0.42, 0, 1, 1) — slow start
• ease-out = cubic-bezier(0, 0, 0.58, 1) — slow finish
• ease-in-out = cubic-bezier(0.42, 0, 0.58, 1) — slow at both ends

The keywords are convenient, but they are a tiny subset of what is possible. The real expressive power comes from custom curves, and that is exactly where a visual CSS easing editor earns its keep. Instead of guessing four decimals and reloading the page, you drag a handle and the motion responds instantly.

How to Use the Cubic-Bezier Easing Editor

Our cubic bezier generator runs entirely in your browser — nothing is uploaded, and it works offline once loaded. Here is the workflow:

• Start from a preset. Pick ease, ease-in-out, or one of the others to get a sensible baseline.
• Drag the two handles. Each pulls the curve toward acceleration or deceleration. Drag a handle below the box or above it to create overshoot.
• Fine-tune with numbers. The four numeric inputs let you type exact values when you need precision.
• Watch the preview. A dot animates across the track using your curve so you feel the motion, not just see the math.
• Copy the CSS. The tool outputs a ready-to-paste transition-timing-function declaration.

Where the Output Goes in Your CSS

The generated value drops into two properties. For transitions:

.button {
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

And for keyframe animations via animation-timing-function:

.card {
  animation: slide-in 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

Tips for Choosing Good Easing

Use ease-out for things entering the screen. Elements that appear should decelerate into place — a fast start that settles gently reads as responsive and confident.

Use ease-in for things leaving. When an element exits, accelerating away feels natural, because the user no longer needs to track it.

Reserve overshoot for personality moments. A little bounce on a toggle or a modal is charming; the same bounce on every micro-interaction becomes exhausting.

Keep durations honest. Most UI motion should land between 150ms and 400ms. The curve shapes the feel; the duration shapes the pace.

Why a Browser Tool Beats Memorizing Numbers

Nobody can intuit how cubic-bezier(0.68, -0.55, 0.27, 1.55) feels by reading it. Motion is something you judge with your eyes, not your arithmetic. A live CSS easing editor closes that gap: you shape the curve, you watch the preview, and you copy the result when it feels right. Try the Cubic-Bezier Easing Editor the next time a transition feels off — a five-second tweak to the curve often does more than any change to duration or distance.