30 Min Calculator - Add, Subtract & Schedule 30-Minute Intervals

Your details

Enter the time you want to count from. Use HH:MM (24h) or H:MM AM/PM.
How many 30-minute blocks to add (positive) or subtract (negative) from the start time.
x 30 min
How many consecutive 30-minute slots to list in the schedule table below.
slots
Enter your hourly rate to see the billable value of the selected intervals. Leave at 0 to skip.
per hour
Resulting time
9:30 AM

The clock time after adding or subtracting the selected intervals

Total duration added30min
Decimal hours0.5h
Total seconds1,800s
30 min
  • Midnight
  • 6 AM
  • 8 AM
  • 9 AM
  • Noon
  • 5 PM
  • 6 PM
  • Midnight

1 x 30 min from 9:00 AM = 9:30 AM

  • 30 min after 9:00 AM is 9:30 AM.
  • That equals 0.5000 decimal hours, useful for payroll software like QuickBooks or ADP.
  • 30 minutes equals 1,800 seconds or 1,800,000 milliseconds - handy for technical scheduling and API timeouts.

Next stepScroll down to see the full 30-minute schedule table for your start time and adjust the number of slots to match your workday.

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