LapperSnapper

Find the time you're leaving on track.

Help Desk

Predictive lap time and delta (Pro)

Last updated 8 days ago

With Pro, the live HUD shows two numbers that change how you drive a session:

  • Delta vs best — how far ahead (green) or behind (red) you are compared to your best lap at this exact point on track, updating continuously.
  • Projected — the final time this lap is on course for, right now.

How it works

The app compares your live position against a reference lap by distance around the circuit — the same math the post-session Compare tab uses, so the number you see on track always matches what the analysis shows afterwards.

The predictor starts working as soon as it has a good GPS fix and a reference lap. On your first ever visit to a track, drive one clean lap — that becomes the reference, and the delta comes alive from lap two.

Reading it on track

  • Try a different line into a corner and watch the delta at the exit: if it went green, the line is faster — you don't have to wait for the lap board.
  • Mini-sector deltas show where in the lap the time came from as you set it.
  • The projection settles as the lap progresses; early-lap swings are normal.

The current, best, and last lap times stay free for everyone — the predictive pair is the Pro layer on top. See What's included in Free vs Pro.

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