Clock in 24 Hour Format: Conversion Chart and Payroll Math

Reading a clock in 24 hour format takes one rule: hours 13 and up are afternoon, so subtract 12 and say PM. The 24 hour clock (military time) numbers the day straight through from 0000 at midnight to 2359, which removes the single biggest source of timesheet errors in shift businesses: the AM/PM mixup.

This page gives you the full conversion chart, the minutes to decimal table payroll actually runs on, and the shift math that uses both.

If you read timesheets, build schedules, or export hours to payroll, you'll meet 24 hour time constantly, because it's what nearly every time clock stores underneath whatever friendly format it displays.

How do you read a clock in 24 hour format?

Instead of running 1 to 12 twice, 24 hour time counts hours 0 through 23. Midnight is 0000, noon is 1200, and the day ends at 2359 before rolling over. Times are written as four digits, hours then minutes, so 0730 is 7:30 in the morning and 1945 is 7:45 in the evening. Spoken in military style, 0730 is "oh seven thirty" and 1400 is "fourteen hundred."

The morning hours look identical to the 12 hour clock with a leading zero: 9:15 AM is 0915. The change happens after noon, when the count keeps climbing instead of resetting: 1:00 PM becomes 1300, 2:00 PM becomes 1400, and so on up to 11:00 PM at 2300. You'll also see the same system written with a colon (07:30, 19:45) in software and schedules; "military time" and "24 hour time" mean the same thing, and the colon is the only cosmetic difference.

The format isn't exotic, either. Hospitals chart on it, airlines and railroads schedule on it, the military runs on it, and most of the world outside North America uses it as the everyday civilian format. US businesses mostly meet it through software, because databases and payroll engines store time as a continuous value; the AM/PM display is a translation layer added afterward for comfort.

24 hour clock conversion in both directions

The military time conversion people ask for most runs one way, 24 hour to AM/PM, and it comes down to four branches. To convert military time to standard time, sort the timestamp into one of these:

• Hour 0: it's 12 AM (midnight). 0045 is 12:45 AM.
• Hours 1 to 11: same hour, AM. 0600 is 6:00 AM, 1130 is 11:30 AM.
• Hour 12: 12 PM (noon). 1215 is 12:15 PM.
• Hours 13 to 23: subtract 12, PM. 1700 is 5:00 PM, 2130 is 9:30 PM.

Minutes never change; only the hour converts. Going the other way, AM/PM to 24 hour time, the mirror rules apply. PM times from 1:00 to 11:59 add 12 to the hour: 3:45 PM becomes 1545, 8:00 PM becomes 2000. AM times from 1:00 to 11:59 stay as written, padded to four digits: 8:05 AM is 0805. The two specials flip the intuition: 12:00 AM (midnight) becomes 0000, and 12:00 PM (noon) stays 1200. A memorable way to hold it: the 12 hour only survives at noon; midnight resets to zero.

The full military time chart, 0000 to 2300

Every hour of the day, both directions:

Print it, tape it by the time clock, and the whole question disappears from your week. New hires stop asking after about two shifts; the pattern sticks fast because only the PM half requires any math at all.

The lookups people actually search

A handful of specific conversions account for most of the confusion, so here they are straight out: 1300 is 1:00 PM, the first afternoon hour and the moment the subtract 12 rule kicks in. 1430 is 2:30 PM, the standard example because both the hour and minutes are in play. 1630 is 4:30 PM, a common shift end. 1745 is 5:45 PM. 2000 is 8:00 PM, spoken "twenty hundred." 2130 is 9:30 PM, a typical restaurant close. And 0001 is one minute past midnight, the first minute of the new day, which is why systems that bill or schedule by date treat 0000 as the boundary.

Reading it out loud

Spoken military convention pads the leading zero with "oh" or "zero": 0500 is "oh five hundred," 0930 is "oh nine thirty." Whole hours from 1000 up are "hundred": 1000 is "ten hundred," 2200 is "twenty two hundred." Times with minutes just read straight through: 1547 is "fifteen forty seven." Civilian workplaces that use 24 hour schedules usually skip the ceremony and say "fifteen thirty" or even "three thirty" once everyone knows the format; the writing is what prevents errors, not the pronunciation.

Minutes to decimal hours: the other conversion payroll needs

The 24 hour clock fixes which times were worked. Decimal hours fix how long. Payroll systems multiply hours by pay rates, so durations have to become decimals: 8 hours 30 minutes is 8.5 hours, not 8.3. That's the entire time clock conversion for payroll: minutes divided by 60. The common values are worth memorizing:

The classic mistake is treating time card minutes as decimals directly: reading 7:45 as 7.45 hours instead of 7.75. That error shorts the employee 18 minutes, or about $5.40 at $18 an hour, every single shift it happens. Across a 10 person crew it compounds into real money and, eventually, a wage claim. Bad decimals travel, too: the same numbers drive payroll and payroll taxes, so an understated hour understates the withholding built on top of it. Payroll overtime comes off those decimals as well, which is why a 0.3 hour slip right at the 40 hour line can flip pay from time and a half to straight time. If your time cards still get totaled by hand, run them through the free time card calculator, which does the minutes to decimal conversion automatically and totals the week.

Overnight shifts and duration math

With both conversions in hand, shift math becomes subtraction. A day shift: in at 0830, out at 1715. Convert to decimals (8.5 and 17.25) and subtract: 17.25 minus 8.5 = 8.75 hours, before any unpaid break. If a 30 minute unpaid lunch applies, the paid total is 8.25 hours. No ambiguity about whether that 5:15 out punch was afternoon or the small hours.

Overnight shifts are where 24 hour time earns its keep. A closer punches in at 2200 and out at 0630. The rollover math: from 2200 to midnight is 2 hours, midnight to 0630 is 6.5, total 8.5 hours. Handwritten as "10:00 to 6:30," the same shift is genuinely ambiguous; it could be a 8.5 hour night or an 8.5 hour day, and on a paper timesheet those get keyed wrong routinely. In 24 hour format, 2200 to 0630 can only mean one thing. Businesses with evening hours, bars, diners, care facilities, security, get the biggest error reduction from switching schedules and timesheets to 24 hour time.

Three more worked examples, since this is the math your payroll depends on: 0645 to 1515 with a 45 minute lunch is 15.25 minus 6.75 minus 0.75 = 7.75 hours. A split shift of 1100 to 1400 plus 1700 to 2130 is 3 + 4.5 = 7.5 hours. And a Friday 2330 to Saturday 0800 shift is 0.5 + 8 = 8.5 hours, with the workweek boundary falling wherever your established workweek starts, a detail that matters for overtime when weekend shifts straddle it.

What happens to overnight shifts when the clocks change?

Twice a year an overnight shift isn't the length the schedule says. 15 USC 260a sets daylight saving time "commencing at 2 o'clock antemeridian on the second Sunday of March of each year and ending at 2 o'clock antemeridian on the first Sunday of November." Both changes land in the middle of the night shift, deliberately.

Take the closer from earlier: in at 2200, out at 0630, normally 8.5 hours.

• Spring forward (March). At 0200 the clock jumps to 0300. The employee is on the floor the whole time, but only 7.5 hours pass. Pay 7.5.
• Fall back (November). At 0200 the clock drops to 0100 and that hour runs twice. The shift is 9.5 hours of real work. Pay 9.5.

Pay the hours worked, not the hours the schedule promised. November is the one that stings: on a 48-hour week the extra hour makes it 49, and it's already in overtime territory, so at an $18 base it costs $27 instead of $18. Across a crew of twelve on that night, you're a few hundred dollars over plan, and it isn't optional.

The sneaky part is what your software does with 0130. On the November Sunday, 0130 happens twice, an hour apart. A system storing bare local wall time ends up with two identical timestamps and no way to order them, which is how a 9.5-hour shift gets saved as 8.5, or how a punch out appears to happen before the punch in. Systems that store the moment in UTC (or keep the UTC offset next to the local time) get it right and nobody has to think about it. Underneath, that usually means keeping the clock in milliseconds from a fixed instant instead of a bare wall time, so the two 0130 punches hold their order. Fair question to ask a vendor in October: what do you store, and what did last November's overnight timesheets look like?

Three things to do before each change. Post the affected shifts in 24 hour format with the real length written beside them (2200 to 0630, 9.5 hrs) so nobody argues about it at 3 AM. Flag those timesheets for manual review instead of auto-approving the week. And check each location if you cross state lines, because a few states sit out daylight saving entirely and their crews work an ordinary night while everyone else doesn't. Building the shift once in employee scheduling software and publishing the corrected hours with it beats patching the week after payroll runs.

What clock in and clock out look like in 24 hour time

The clock in definition hasn't changed since the punch in clock hung by the shop door: it's the recorded moment a shift starts, and clocking out records the moment it ends. What changed is where the record lands. A wall unit stamps a card, a web clock stamps a browser session, and a clock in and clock out app does the same job from a phone on a job site. All three capture an hour and a minute. Only the display format differs.

Write the pair in 24 hour time and the shift reads identically to everyone who touches it: in 0545, out 1415. In a facility where people clock in 24 hours a day on rotating shifts, that consistency is the difference between a timesheet you can key without thinking and one you have to interpret. Every clock in clock out pair is also a duration, and durations are what payroll wants, so if you're checking a week by hand, a clock in and clock out calculator spares you the subtraction across midnight.

Why time clocks and payroll run on 24 hour time

Federal recordkeeping rules require employers to keep records of hours worked each workday and total hours worked each workweek (29 CFR 516.2) for nonexempt employees. Those records are only as good as their timestamps, and unambiguous timestamps are exactly what the 24 hour clock provides. Payroll systems compute on continuous time values internally even when they display AM/PM to be friendly, and every export format the major providers accept ultimately reduces punches to decimal hours.

Rounding is the other place the regulations meet the clock. Under 29 CFR 785.48, employers may round punch times to the nearest 5 minutes, one tenth, or quarter of an hour, provided the rounding doesn't systematically underpay over time. Under quarter hour rounding, the split falls at 7.5 minutes: a punch at 0807 rounds back to 0800, a punch at 0808 rounds forward to 0815. That's the source of the "7 minute rule" managers half remember. Neutral application is the legal requirement: the same math applies to clock ins and clock outs alike, so the rounding gives and takes evenly over time. A system that always rounds start times up and end times down fails the test and creates back pay liability with every shift. Quarter hour rounding pairs with the decimal table above: each quarter is exactly 0.25 hours, which is why the quarter hour became the traditional payroll increment in the first place. Modern systems make rounding optional rather than necessary, since exact punches are already decimal underneath.

You don't need employees to think in military time to get the benefit. Most time clock software accepts and displays either format while storing the unambiguous version underneath. Teaching the team to read the chart above takes ten minutes, and it permanently ends the "did you mean AM or PM?" text thread.

The conversion mistakes that cost real money

Three errors account for nearly all of it, and each carries a number.

• Reading minutes as decimals. 7:45 keyed as 7.45 instead of 7.75 shorts the employee 0.3 hours a shift. On a 10 person crew, five shifts a week, 50 weeks, that is 750 hours a year, or $13,500 at an $18 base. It also stops looking like an accident once it repeats, which is how a keying habit turns into a wage claim.
• Guessing AM or PM on a handwritten card. A closing shift written "10:00 to 6:30" gets keyed as a day shift. Written 2200 to 0630 it has exactly one reading, and the person keying it doesn't need to know the schedule.
• Losing the workweek boundary. Overnight shifts straddle midnight, and midnight is where a workweek can start. 29 CFR 516.2 requires you to keep the "time of day and day of week on which the employee's workweek begins" alongside hours worked each workday and total hours each workweek. If you can't say which week a Friday-night-into-Saturday shift belongs to, you can't compute overtime correctly, and you can't prove you did.

All three vanish the moment punches are recorded by a system instead of transcribed by a person. Every hop between a clock and a paycheck is one more place to drop a digit.

From punches to payroll without retyping

Every conversion on this page exists because hours have to travel from a clock to a paycheck, and each manual hop, reading handwriting, converting formats, turning minutes into decimals, adding a week by hand, is a chance to get it wrong. The fix is to collapse the hops. With Kloqk's free employee time clock, employees punch in and out on a kiosk or their phone, the system stores exact unambiguous timestamps, totals each workweek in decimal hours, and exports approved time straight into Gusto payroll, ADP, QuickBooks, Paychex, and the other major payroll providers in the format each expects. Nobody converts anything by hand, so nobody converts anything wrong.

For the leftover cases, a paper card from a jobsite, a disputed week, a what-if, the free time card calculator and timesheet calculator apply every rule on this page in a few clicks: 24 hour or AM/PM input, automatic minutes to decimal conversion, break deductions, and weekly totals with overtime flagged.

Next step: pick one format for schedules and posted timesheets, put the two tables from this page next to the clock, and let the software hold the conversions from there. The AM/PM mixup is one of the few payroll errors you can eliminate completely, this week, for free.