Time Duration With Days, Hours & Minutes (Multi-Day SLA & Outage Timestamps)

Never let a 77-hour server outage display as "05:45" because of 24-hour clock wrap!

Subtracting two date-time timestamps in spreadsheets returns elapsed days as a floating-point serial number: for example, from 2026-05-01 08:30 to 2026-05-04 14:15 is 3.2395833 days (77.75 total hours). If you format that cell with standard clock format hh:mm, spreadsheets silently drop the integer days (3 * 24 = 72 hours) and display "05:45"—underreporting a 3-day SLA breach by 72 hours!

Decomposing the serial delta (B3 - B2) explicitly with INT(B3 - B2) for whole 24-hour days, HOUR(B3 - B2) for the remaining 0–23 hours, and MINUTE(B3 - B2) for the remaining 0–59 minutes produces an unmistakable human-readable string "3d 5h 45m" that works identically in Excel and Arte Sheets—while ROUND((B3 - B2) * 24, 2) supplies exact total decimal hours (77.75 hr) for SLA billing and MTTR averages!

Multi-Day Elapsed Duration String ("Xd Yh Zm")

Validates End >= Start, then extracts whole days via INT and sub-day hours/minutes via HOUR and MINUTE.

=IF(B3 < B2, "End Before Start", INT(B3 - B2) & "d " & HOUR(B3 - B2) & "h " & MINUTE(B3 - B2) & "m")

Total Unwrapped Elapsed Decimal Hours

Multiplies elapsed serial days (B3 - B2) by 24 hours/day for numeric MTTR and payroll calculations.

=IF(B3 < B2, "End Before Start", ROUND((B3 - B2) * 24, 2))

Further reading

• Microsoft Support — HOUR function
• Microsoft Support — MINUTE function