GPXFIT

Time Shift

The Time Shift tool lets you adjust all timestamps in your track by a specified offset. This is useful for correcting timezone errors or fixing a GPS device with an incorrect clock.

Features

Shift by Offset

Adjust all timestamps by a specific number of hours and/or minutes.

Controls:

  • Hours (-23 to +23) - Use +/- buttons or enter a value directly
  • Minutes (-59 to +59) - Use +/- buttons or enter a value directly

Quick Adjust buttons:

  • -1h, -30m, +30m, +1h for common adjustments
  • Reset button to return to zero offset

Timezone Correction presets:

  • UTC to PST (-8h) - US Pacific
  • UTC to EST (-5h) - US Eastern
  • UTC to CET (+1h) - Central European
  • UTC to CST (+8h) - China Standard

Set Start Time

Instead of specifying an offset, you can set the exact start time you want for your track. All other timestamps will shift proportionally.

How to use:

  1. Select "Set Start Time" mode
  2. Use the date/time picker to choose the desired start time
  3. The tool calculates the required offset automatically

This is useful when you know what time an activity actually started but your GPS recorded the wrong time.

Preview

The preview section shows:

  • Original Start/End - The current timestamps in your track
  • New Start/End - What the timestamps will become after shifting
  • Duration - Shows the track duration (unchanged by time shifting)

When to Use

Timezone Correction

Your GPS device may record timestamps in UTC or a different timezone than where you were. Common scenarios:
  • GPS recorded in UTC, you want local time
  • Device set to wrong timezone for a trip abroad
  • Syncing tracks from devices in different timezones

Wrong GPS Clock

Some GPS devices lose their time setting when the battery dies or is removed. The device may:
  • Default to an incorrect date (often 1970 or 2000)
  • Be off by hours due to a missed sync

Combining Tracks

When merging tracks from different sources, timestamps may need adjustment to align properly.

How It Works

  • All track points with timestamps are shifted by the same offset
  • Route points (if present) are also shifted
  • The relative timing between points is preserved
  • Track duration remains unchanged

Notes

  • The tool requires your track to have timestamp data
  • If no time data exists, the Time Shift button will be disabled
  • Changes can be undone using the undo feature
  • Timestamps are stored in ISO 8601 format (UTC)
  • The preview shows local time for readability