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Sprite Animation Timing Calculator

Frame duration, sheet dimensions, refresh-rate alignment and ready-made CSS steps() keyframes for sprite sheet animation.

About this tool

Sprite Animation Timing Calculator

Frame duration, sheet dimensions, refresh-rate alignment and ready-made CSS steps() keyframes for sprite sheet animation.

Sprite Animation Timing Calculator converts a frame count and a target frame rate into the numbers a sprite sheet animation actually needs: frame duration in milliseconds (1000 ÷ fps), full cycle length, sheet dimensions from the frame size and column count, and the CSS steps() keyframes that drive it. It also checks the rate against your display refresh — 24 fps on a 60 Hz screen gives 2.5 refreshes per frame, so frame lengths alternate and the motion judders — and flags GIF delays below the 2-centisecond floor browsers enforce.

How to use Sprite Animation Timing Calculator

  1. 1

    Open Sprite Animation Timing Calculator on AltFTool — it loads instantly in your browser.

  2. 2

    Enter 'Frame count', 'Frame rate (fps)', 'Frame width (px)', 'Frame height (px)' and 'Frames per row on the sheet'.

  3. 3

    Pick your 'Display refresh rate (Hz)' and set the 'CSS selector' the generated rule should target.

  4. 4

    Read 'Duration of one frame', 'Display refreshes per frame' and 'GIF frame delay', then press 'Copy CSS'.

Why use Sprite Animation Timing Calculator

  • Refresh-aware

    Tells you when a rate does not divide the display refresh evenly, and which nearby rate does.

  • Grid and strip

    Generates single-axis CSS for a strip and paired horizontal/vertical animations for a grid sheet.

  • Reduced motion included

    The generated CSS ships with a prefers-reduced-motion block that stops the animation.

Common use cases

  • Pick a frame rate that divides 60 Hz evenly so a walk cycle plays without stutter.
  • Work out the sheet dimensions before exporting frames from an animation tool.
  • Generate the steps() keyframes for a 4 × 3 grid sheet without deriving the background positions by hand.
  • Check whether an animation can ship as a GIF or has to be video because the frame delay is too short.

Frequently asked questions

How do I calculate sprite animation frame duration?

Divide 1000 by the frame rate: at 12 fps each frame lasts 83.33 ms, at 24 fps 41.67 ms, and at 30 fps 33.33 ms. The full cycle is the frame count divided by the rate — 12 frames at 12 fps runs for exactly one second.

What frame rate should a sprite animation use?

Pick a rate that divides your display refresh into a whole number. On a 60 Hz screen that means 60, 30, 20, 15, 12 or 10 fps, where each frame is held for 1, 2, 3, 4, 5 or 6 refreshes. 24 fps is the classic film rate but needs 2.5 refreshes per frame on a 60 Hz panel, so frames alternate between two and three refreshes and the motion visibly judders.

How does CSS steps() work with a sprite sheet?

Animate background-position from 0 to minus the full sheet width with steps(N), where N is the number of frames in the row. steps() defaults to jump-end, meaning the last keyframe value is never displayed, so the animation lands on each of the N frames exactly once before looping.

Why is my GIF animation slower than I set it to?

GIF stores frame delay in hundredths of a second, and browsers clamp anything below 2 centiseconds — historically substituting 10 cs instead. That caps a GIF at roughly 50 fps and often much less. If the calculated delay comes out under 2 cs, export the animation as video or CSS rather than GIF.

Embed this tool on your site

Add the Sprite Animation Timing Calculator widget to your blog or website — free, responsive, no signup. Just keep the “Widget by AltFTool” credit link visible.

<iframe src="https://www.altftool.com/embed/widget/sprite-animation-timing-calculator"
  title="Sprite Animation Timing Calculator — free AltFTool widget"
  width="100%" height="640" style="border:0;border-radius:12px;overflow:hidden"
  loading="lazy" referrerpolicy="no-referrer-when-downgrade" allow="clipboard-write"></iframe>
<p style="font-size:12px;margin:4px 0 0">Widget by <a href="https://www.altftool.com/tools/all/sprite-animation-timing-calculator?utm_source=embed&amp;utm_medium=widget" rel="nofollow">AltFTool — free online tools</a></p>

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