What Is a CSS Animation Timing Function?
Animation timing functions control how an animation progresses over time. Instead of moving at a constant speed from start to finish, timing functions let you create acceleration, deceleration, and complex motion curves that make your UI feel alive.
The most common timing functions are cubic bezier curves—mathematical functions defined by four control points that determine how quickly properties change during an animation. CSS provides keywords like ease, ease-in, and ease-out, but custom bezier curves give you precise control.
Great animation timing is invisible. Users don't notice the bezier curve—they just feel that your interface responds naturally. Bad timing makes animations feel sluggish, jarring, or robotic.
What Our CSS Animation Generator Does
Turn abstract bezier curves into production-ready animation code
Our CSS animation generator provides an interactive canvas where you drag control points to shape your timing curve. You see the mathematical function visualized in real-time, so you understand exactly how your animation will feel before you write a line of code.
You can preview your curve applied to different properties—translation, scale, opacity, and rotation. The same bezier function feels completely different depending on what you're animating. Our multi-property preview helps you choose the right curve for your specific use case.
Who Uses This Tool?
- Front-end developers fine-tuning microinteractions for production apps
- UI designers creating timing specifications for developer handoffs
- Animation enthusiasts learning how bezier curves affect motion design
- Teams standardizing animation timing across design systems
How the Generator Works
The bezier canvas shows a coordinate system where X represents time (0 to 1) and Y represents progression (0 to 1). The curve starts at point (0,0) and ends at (1,1). You control the shape between those points by dragging two handles.
The first handle (P1) controls the initial acceleration. Pull it upward for a sharp start. Push it down for a slow, gradual beginning. The second handle (P2) controls the deceleration. Position it high for an abrupt stop, low for a gentle ease-out.
Enable extended range mode to push handles beyond the standard 0-1 bounds. This creates overshoot effects where your animation briefly exceeds its target before settling back. Perfect for bouncy, playful UI elements.
The timeline scrubber lets you pause at any millisecond and inspect the exact state of your animation. Drag the playhead to see how your curve translates to real movement. This is essential for debugging complex timing issues.
Ghost comparison mode overlays your custom curve against standard timing functions. Use this to validate whether your curve actually improves the feel, or if you should stick with a CSS keyword.
Using Our CSS Animation Generator: Step by Step
Choose a preset or start from scratch
Select from standard CSS keywords (ease, ease-in, ease-out) or popular presets to get started quickly. Each preset provides a proven timing function for common use cases.
Adjust the bezier curve handles
Drag the control points on the interactive canvas to shape your curve. The first handle controls the start behavior, the second controls the end. Watch the preview update in real-time.
Set duration and delay
Configure how long the animation runs and when it starts. Duration affects the overall feel—200ms feels snappy, 2000ms feels cinematic. Delay creates sequenced animations.
Preview across multiple properties
See how your curve affects different animation types—translation, scale, opacity, and rotation. The same curve can feel completely different depending on what property is animated.
Compare with reference curves
Enable ghost comparison mode to see your custom curve alongside standard timing functions. This helps you understand if your curve is actually better than the defaults.
Export your code
Copy production-ready code in CSS, Tailwind, SCSS, or JavaScript format. The code includes proper syntax and can be pasted directly into your project.
Understanding Bezier Curves
The Math Behind the Magic
A cubic bezier curve is defined by four points: two fixed endpoints (start and end) and two movable control points. The curve is calculated using a polynomial function that smoothly interpolates between these points.
In CSS, you only specify the two control points because the endpoints are always (0,0) and (1,1). The syntax cubic-bezier(x1, y1, x2, y2) maps directly to these control point coordinates.
Reading the Curve
A steep curve means rapid change—your animation accelerates or decelerates quickly. A shallow curve means gradual change—smooth, controlled motion. The steeper the curve at any point, the faster the change at that moment.
If the curve goes above 1 on the Y-axis, your animation overshoots its target. If it dips below 0, it anticipates by briefly moving backward before going forward. These effects create playful, organic-feeling motion.
Common Animation Use Cases
Button Hover States
Fast in, slow out creates a responsive, polished feel. Use ease-out or a custom curve like cubic-bezier(0, 0, 0.2, 1) with a duration around 150-200ms.
Modal Entry
Combine scale and opacity with ease-out timing. A duration of 300-400ms feels smooth without being sluggish. Add a slight overshoot for playful brands.
Page Transitions
Use ease-in-out for symmetrical transitions that feel natural. Duration depends on the distance—short slides can be 250ms, full-screen transitions need 400-600ms.
Loading Indicators
Linear timing works well for spinners and progress bars because users expect constant motion. For pulsing loaders, use ease-in-out to create a breathing effect.
Animation Best Practices
Do
Test on real devices. Timing that feels good on a powerful desktop might lag on mobile.
Keep durations under 500ms for UI feedback. Longer animations frustrate users waiting for responses.
Use ease-out for entrances and ease-in for exits. This mirrors natural motion and feels intuitive.
Maintain consistency across your app. Standardize timing functions in your design system.
Don't
Don't use complex curves where simple ones work. Ease-out solves most use cases.
Don't animate everything. Too much motion creates visual noise and slows perceived performance.
Don't ignore prefers-reduced-motion. Respect user accessibility preferences.
Don't use overshoot effects for critical UI. Bouncing submit buttons feel unprofessional.
Animation Performance
The timing function itself has minimal performance impact—the browser handles cubic bezier calculations efficiently. What matters is what you're animating and how often.
Stick to transform and opacity for the smoothest animations. These properties are GPU-accelerated. Animating layout properties like width, height, or margin forces reflows and kills performance.
Use will-change sparingly to hint to the browser which properties you'll animate. Overusing it wastes memory. Apply it just before the animation starts and remove it when done.
Test with Chrome DevTools Performance tab. Record while your animations run and look for dropped frames. Aim for consistent 60fps on mid-range devices.
Using Bezier Curves Across Frameworks
React & Framer Motion
Framer Motion accepts bezier arrays: ease: [0.25, 0.1, 0.25, 1]. This maps directly to our generator output. Use transition props to control duration, delay, and repeat.
Vue & Transition Component
Vue's built-in transition component uses standard CSS timing functions. Add your custom bezier to transition classes. Use mode="out-in" to sequence enter/exit animations.
GSAP
GSAP supports CSS bezier strings: ease: "cubic-bezier(0.25, 0.1, 0.25, 1)". For complex sequences, use GSAP's built-in eases like Power2.easeOut which are optimized for performance.
Web Animations API
The native JavaScript API uses easing strings identical to CSS. Perfect for vanilla JS projects where you want full control without adding library weight.
When to Use Custom Timing Functions
Use custom curves for
- Branded motion design that needs to match specific guidelines
- Complex interactions where standard curves feel generic
- Playful UI elements that benefit from bounce and overshoot
- Microinteractions that need precise timing control
Stick with defaults for
- Most UI transitions—ease-out handles 80% of use cases
- Enterprise apps where consistency matters more than personality
- Performance-critical animations where standard curves are optimized
- Quick prototypes where speed to market is priority
Start Creating Custom Animations Now
Our CSS animation generator gives you the tools to create professional timing functions in seconds. Experiment with curves, preview effects, and export production-ready code. Whether you're polishing microinteractions or building a complete design system, get the timing right with our free tool.
Frequently Asked Questions
Common questions about CSS animations and bezier curves
What is a cubic bezier curve in CSS?+
A cubic bezier curve is a mathematical function that controls animation timing in CSS. It uses four control points to create smooth transitions between start and end states, allowing precise control over acceleration and deceleration.
How do I use custom timing functions in my CSS?+
Use the cubic-bezier() function in your transition or animation properties. For example: transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1). Our generator provides ready-to-copy code for CSS, Tailwind, and JavaScript implementations.
What's the difference between ease, ease-in, and ease-out?+
Ease starts slowly, accelerates, then decelerates. Ease-in starts slowly and accelerates. Ease-out starts fast and decelerates. Each creates a different feel—ease feels natural, ease-in feels responsive, ease-out feels smooth to stop.
Can I create bounce effects with cubic bezier?+
Yes, by extending control points beyond the 0-1 range. Values above 1 create overshoot (bounce), while values below 0 create anticipation effects. Our generator supports extended ranges for advanced animations.
Do timing functions affect performance?+
The timing function itself has minimal impact. What matters is what you're animating. Stick to transform and opacity for GPU-accelerated animations. Avoid animating layout properties like width or height.
Should I use this generator or stick with CSS keywords?+
Start with CSS keywords—they handle most cases. Use custom curves when you need branded motion, playful interactions, or precise control that standards don't provide. Always test that your custom curve actually improves the feel.