🔍 /

Clock Time Sorter

Sort a list of clock times in ascending or descending order. Supports 12-hour and 24-hour formats with seconds. Paste, sort, copy.

User Rating 0.0 ★★★★★
Total Usage 0 times
Category Time
Supports 24h (HH:MM, HH:MM:SS) and 12h (h:MM AM/PM) formats
Sorted times will appear here
Is this tool helpful?

Your feedback helps us improve.

★ ★ ★ ★ ★

About

Sorting a list of clock times is not a simple alphabetical operation. A naive string sort places 9:00 AM after 10:00 AM because the character 9 has a higher code point than 1. The correct approach converts each time to a canonical numeric value - total seconds since midnight - then sorts on that integer. This tool parses mixed-format inputs (both 24-hour and 12-hour notation, with or without seconds) and produces a correctly ordered list. It handles edge cases such as 12:00 AM (midnight, 0 seconds) and 12:00 PM (noon, 43200 seconds) which frequently cause errors in manual sorting.

Miscalculating time order affects scheduling, log analysis, shift planning, and data pipeline sequencing. A single inversion in a timetable can cascade into missed connections or compliance violations. This tool validates each entry, flags unparseable lines, removes duplicates on request, and exports the result in your preferred format. It approximates no values - every output is deterministic and exact.

time sorter sort times clock time order time list sorter chronological sort time organizer

Formulas

Each time string is converted to a single integer representing total seconds elapsed since midnight (00:00:00):

S = h × 3600 + m × 60 + s

Where S is the sort key (total seconds), h is the hour in 24-hour notation (0 - 23), m is the minute (0 - 59), and s is the second (0 - 59). For 12-hour input, the conversion to 24-hour h follows:

h24 = {
0 if h12 = 12 and AMh12 if AM and h12 ≠ 12h12 + 12 if PM and h12 ≠ 1212 if h12 = 12 and PM

Sorting is performed on S using a comparison function: Sa − Sb for ascending, Sb − Sa for descending. Duplicate detection compares S values - two entries with identical S are duplicates regardless of original format.

Reference Data

Input FormatExampleParsed As (24h)Seconds Since MidnightNotes
24h HH:MM14:3014:30:0052200Standard ISO-like notation
24h HH:MM:SS08:05:3308:05:3329133Includes seconds
12h h:MM AM9:15 AM09:15:0033300Leading zero optional
12h hh:MM PM02:45 PM14:45:0053100PM adds 12 hours (except 12 PM)
12h hh:MM:SS AM11:59:59 AM11:59:5943199One second before noon
12h 12:00 AM12:00 AM00:00:000Midnight - earliest time of day
12h 12:00 PM12:00 PM12:00:0043200Noon - not AM
12h 12:59 PM12:59 PM12:59:0046740Still in the 12 PM hour
12h 12:01 AM12:01 AM00:01:0060Just past midnight
24h 00:0000:0000:00:000Midnight in 24h format
24h 23:59:5923:59:5923:59:5986399Last second of the day
24h single-digit hour6:3006:30:0023400Leading zero optional in 24h
Invalid25:00 - - Hour > 23 rejected
Invalid13:00 PM - - 13+ with AM/PM rejected
Invalidabc - - Non-time string rejected

Frequently Asked Questions

Every entry is independently parsed. The parser first checks for an AM/PM suffix. If found, it applies the 12-to-24-hour conversion rules. If no suffix is found, the time is treated as 24-hour notation. Both types are converted to total seconds since midnight and sorted on that single numeric value. The output format you select (12h or 24h) is then applied uniformly to all entries.
Invalid entries are separated into an "Errors" section displayed below the sorted results. The tool reports the original text and its line number. Common rejection reasons include hours exceeding 23 (in 24h mode) or 12 (in 12h mode), minutes or seconds exceeding 59, and non-numeric characters. The entry "13:00 PM" is rejected because 13 is invalid in 12-hour notation.
Yes. Duplicate detection operates on the canonical seconds value, not the raw string. Both "2:30 PM" and "14:30" resolve to 52200 seconds. When "Remove Duplicates" is enabled, only the first occurrence is kept. This is the correct behavior for schedule deduplication where the same moment is recorded in different notations.
12:00 AM is midnight and maps to 0 seconds (hour 0). 12:00 PM is noon and maps to 43200 seconds (hour 12). 12:59 AM maps to hour 0, minute 59 (3540 seconds). 12:59 PM maps to hour 12, minute 59 (46740 seconds). These follow the standard 12-hour convention used in the United States and are the most common source of sorting errors.
Yes. The parser splits input on newlines, commas, semicolons, and tab characters. Mixed delimiters within one input are supported. Each resulting token is trimmed of whitespace before parsing. Empty tokens are silently discarded.
There is no hard-coded limit. The sort algorithm runs in O(n log n) time. In practice, browsers handle lists of 50,000+ entries in under 100 milliseconds. The textarea may become sluggish with extremely large pastes (100,000+ lines), but this is a DOM rendering constraint, not a sorting constraint.