Which statement best defines delta time in games?

• A. The time elapsed since the game started.
• B. The time elapsed since the last frame.
• C. The time required to render a frame.
• D. The time between user inputs.

Answer: (B)

Delta time is the amount of real time that has passed since the previous frame was shown. This frame-to-frame interval is used to make game updates, like movement and physics, run at the same real-world speed regardless of how fast or slow the game is rendering.

Using delta time lets you multiply a motion or physics value (for example, velocity in units per second) by the time elapsed this frame. If the game runs at a high frame rate, delta time is small, so the per-frame movement is small. If the frame rate drops, delta time increases, and the movement scales up accordingly, keeping motion smooth and consistent over real time.

This is different from the total time since the game started, and it’s not exactly the time spent rendering a single frame, or the time between user inputs. Delta time specifically measures the gap between consecutive frames, which is what you use to keep time-based updates frame-rate independent.