How to Fix Framerate-Dependent Movement in Unity

A character that sprints on a 144 Hz monitor and crawls on a 30 FPS laptop is moving per frame, not per second. deltaTime converts frame steps into real time so speed is constant everywhere. Here is the right way to apply it.

How to fix it

1. Multiply movement by Time.deltaTime

In Update, transform.position += velocity times Time.deltaTime. deltaTime is the seconds since the last frame, so the object covers the same distance per second regardless of frame rate.

2. Use fixedDeltaTime in FixedUpdate

Physics runs in FixedUpdate at a fixed step; there, use Time.fixedDeltaTime (or just rely on the fixed step). Mixing Update's deltaTime into physics produces inconsistent forces.

3. Never scale by frame count

Anything that advances by a constant each frame — timers, animations, spawn rates — drifts with frame rate. Express it in seconds and multiply by deltaTime so it behaves identically on every machine.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.