12 and 24 Hour Clock Converter
Convert AM/PM, 24-hour clock time and compact military-style digits without changing the time zone.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Parse one clock time and reformat the same seconds-since-midnight value.
24-hour hour=(12-hour hour mod 12)+(PM ? 12 : 0)
Worked example
13:45 is 1:45 PM. Under the explicit convention here, 12:00 AM is 00:00 midnight and 12:00 PM is 12:00 noon.
Assumptions and input details
Minutes and seconds must be 00–59. Compact inputs use exactly four or six digits. Midnight means the start of an unspecified day; 24:00 is rejected to avoid assigning a date. No time zone, daylight-saving, duration, date or leap-second conversion is performed.
References: Royal Museums Greenwich: noon, midnight and 24-hour notation
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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