Lap comparison, mobile and web
Compare laps side by side to see where you gained or lost time.
A lap table tells you a lap was 0.495 s faster. It does not tell you that it was 0.2 s down after T4-T5-T6 and found three tenths in a single corner. That is the difference between a time and an analysis.
- Reference
- Lap 4 1:58.333
- Compared
- Lap 9 1:57.838
- Delta at the line
- −0.495 s
- Session
- 9 Oct 2026, Autodrom Most, 25 Hz
Delta along the lap
Drag along the lap distance. Above the line you are slower than the reference, below it you are faster, the same way up as in the analyzer.
Delta at 3 750 m
−0.53 s
Faster
Slower
- Position
- 3 750 m
- Sector
- S2
- Cumulative delta
- −0.53 s
- Reading
- T15: three tenths found in one corner
In the app, clicking a point on this curve moves the track map and the onboard video to the same position along the lap, so you can look at the corner where the curve turns.
The workspace
Five laps, one screen.
Add the laps you want to see, follow the delta to where it climbs, then click it. The map, the onboard video and the zone bar under the charts all move to that point on the lap.
Every lap, every sector, in one table.
Best lap in blue, best sector of the session in green.
On the phone, in the paddock
Sector splits, before you take the helmet off.
Sector splits and the best-lap flag are on the phone as soon as you stop recording, so you can decide what to try on the next run without leaving the pit lane.
The full comparison waits for the browser and a coffee: the delta curve, two lines on the map, sessions months apart.
Selected Lap 9 1:57.838 vs Lap 4 Session best: 0.495 s up on lap 4, three tenths of it in T15
| Lap | S1 | S2 | Lap time | vs best | Note |
|---|---|---|---|---|---|
| 74.466 | 47.018 | 2:01.484 | +3.646 | An early lap | |
| 72.024 | 46.309 | 1:58.333 | +0.495 | The reference lap | |
| 72.593 | 46.224 | 1:58.816 | +0.978 | ||
| 71.953 | 45.885 | 1:57.838 | best | Session best: 0.495 s up on lap 4, three tenths of it in T15 | |
| 71.878 | 47.344 | 1:59.221 | +1.383 | Best sector 1 | |
| Best | 71.878 | 45.885 | 1:57.763 | −0.075 | Best sectors joined up. The theoretical best goes finer, per zone: how it works |
Five of the eleven laps of this session. One sector line splits this layout in two. Pick any lap to compare it against lap 4.
On the map
Two lines, a few meters apart.
The delta curve says where on the lap. The map says what. Both laps are drawn on the layout and colored by speed or by delta, so the braking point, the apex and the exit are three visible differences rather than three opinions.
This session was recorded with a 25 Hz receiver. At 178 km/h, the top speed of lap 9, that is 2.0 m between samples, enough resolution to see that you turned in earlier, not just that you were slower.
- Color the line by speed, or by delta against the reference
- Overlay laps to compare entry, apex and exit
- Click any point to move the delta curve and the video with it
Across sessions
Am I actually faster, or was it just a cold morning?
Comparison is not limited to one session. Pick laps from different days and Vetkuro lines them up along the layout distance, so the same corner matches even though the recordings are years apart. The conditions travel with each session, so you can see what changed and what you changed.
15 April 2023
1:58.201
S1 71.966S2 46.235
9 October 2026
1:57.838
S1 71.953S2 45.885
- Sector 1
- −0.013 s
- Sector 2
- −0.350 s
- Over the lap
- −0.363 s
Three and a half years later, same car, and 0.363 s faster, nearly all of it in sector 2. A gain spread evenly across the lap usually means the car or the track changed: four degrees of air temperature, for instance. A gain concentrated in one sector is more likely to be you.
Your own two laps, compared like this.
Record on the phone you already own. The comparison is ready in the paddock.
The axis
Two laps almost never share a timestamp.
This is the quiet reason most lap comparisons are useless. If you line up two laps by the clock, the faster lap arrives at every corner earlier, and by the back straight you are comparing a braking zone against a full-throttle section.
Vetkuro lines laps up by distance travelled instead. 2 100 m into the lap is the same piece of tarmac on every lap you ever recorded there, no matter how fast you got to it, what device recorded it, or which day it was.
Everything downstream depends on it. The delta curve, the overlaid traces, the two lines on the map and the sector splits are all statements about a place, which is the only kind of statement you can act on next time you go through that corner.
Aligned by clock time
At 100 s into the lap, lap 9 is already braking for T15 and lap 2, an early lap, is still on the straight before it.
Lap 9 at 3 510 mLap 2 at 3 377 m
Comparing two different corners.
Aligned by lap distance
At 2 100 m, both laps are at the same point in T9, whatever the clock says.
Lap 9 at 62.95 sLap 2 at 64.77 s
The 1.82 s between them is the answer.
- Laps from different days line up on the same layout
- Sources sampling at different rates land on one axis
- Every trace on a chart stack shares that axis
What a comparison cannot tell you
Being straight about the limits is the point. A tool that hides them makes you trust the wrong number.
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Whether the data is good enough
If the GPS fix was intermittent over part of a lap, the delta over that part is a guess. Vetkuro says so rather than smoothing it into a confident curve.
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Why the other car was faster
A comparison against a car with 100 kW more says nothing you can act on. Compare against your own laps first, and against similar cars after that.
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What to change in the car
Delta shows the symptom. Whether it is tire pressure, a damper setting or your entry speed is a conversation for you and whoever knows the car.
When the signal is weak, the app says so.
While you record, the app shows the GPS signal as good, moderate or weak, so a poor fix is something you see in the pit lane rather than discover in the analyzer. Zone boundaries are drawn from the laps with the best GPS, not from every lap you drove.
Background reading
How to read a delta graph
A delta graph is one number plotted along the lap: how far ahead or behind you are compared to the reference lap at the same point on the track. Four things to look for, in order.
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The slope, not the height
Where the line is steep, you are losing or gaining time fast. A flat line at +0.300 s means you are behind but driving that section exactly as well. Chase the slopes.
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Where it turns
Lap 9 is 0.2 s down after T4-T5-T6, level by T10 and 0.495 s up at the line. No single heroic corner: T7, T9 and T12-T13-T14 each gave a tenth, and T15 gave three.
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Corner exit, one corner later
Time lost on exit shows up down the following straight, not at the apex. Read the corner slightly before the point where the line starts climbing.
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Check the reference is fair
Measure against a lap that was not driven like the others and you get a dramatic graph and no insight. Lap 2 here was an early lap, 3.6 s off the best. Against it, every other lap looks brilliant.
