How the time card calculator works

Reading what you type

Each day is read as a list of punches: in, out, in, out. "855a-530p" is in at 8:55 am and out at 5:30 pm. "8-12, 12:30-4:30" is two work periods with a 30 minute gap. A time without am or pm is read the way shifts usually run: a start from 6 to 11 is morning, a start from 1 to 5 is afternoon, and each later time is placed after the one before it. An out time earlier than its in time crossed midnight. The note under each day always says exactly what was read.

Hours and the lunch break

A day's hours are the sum of its work periods. When a day is typed as one range with no gap, the unpaid lunch you pick (30 minutes unless you change it) comes off if the day is over 5 hours. When a day has two or more work periods, the real gaps are the breaks and nothing else comes off.

Overtime rules

Each rule set is a small table in the code, with a link to its source. Daily overtime is worked out first, day by day. Then the regular hours are added up through the workweek, and any regular hours past 40 become weekly overtime. An hour is never counted as overtime twice.

The overtime rules the calculator applies, with their sources

Rules	What is applied	Source
Federal	1.5x over 40 hours in a workweek	29 CFR 778
California	1.5x over 8 a day and 40 a week; 2x over 12 a day; 7th day in a row: first 8 hours 1.5x, the rest 2x	Labor Code 510
Alaska	1.5x over 8 a day and 40 a week	AS 23.10.060
Nevada	1.5x over 40 a week; over 8 a day only below $18.00 an hour (1.5 times the $12.00 minimum wage)	NRS 608.018
Colorado	1.5x over 12 a day and 40 a week	COMPS Order

The rules were last checked against these sources on November 15, 2026. Minimum wages, and so the Nevada threshold, are checked again every January and July.

Money: exact minutes, cents once

Pay is worked out from whole minutes, never from hours rounded to two decimals. Regular minutes times the rate, plus overtime minutes times 1.5 times the rate, plus double time minutes times 2 times the rate, divided by 60. The result is rounded half up to the cent once, at the very end.

That is why a total here can differ by a few cents, or a few dollars, from a calculator that rounds each day to two decimals first. For one week of 8:55 am to 5:30 pm Monday to Friday and 9 to 1 on Saturday, with a 30 minute lunch at $18 an hour, this calculator gives $839.25. One popular free calculator shows $844.56 for the same week with its default settings.

Pay periods: overtime stays per workweek

Run payroll pays every week, every two weeks or twice a month. Overtime is always counted per workweek, never per pay period (29 CFR 778.104). Two weeks of 48 and 32 hours have 8 hours of overtime, even though the period is exactly 80 hours.

Twice-a-month periods (the 1st to the 15th, the 16th to the end) cut through workweeks. Days of the first workweek that fall before the period were paid last period, but they still count toward that week's 40 hours, so the grid asks for them and does not pay them again. Overtime a workweek adds after the period ends is paid next period, when the workweek ends (29 CFR 778.106). Overtime is counted in day order, so a later day never changes how an earlier day was paid, and the two halves of a month always add up to the same pay as the whole month counted week by week. A test checks that on random hours under every rule set.

Minimum wage

Every rate is checked against the highest minimum that applies on the last day of the pay period: the federal $7.25, the state (California $16.90, Alaska $14.00 from July 1, 2026, Nevada $12.00, Colorado $15.16) and, if you pick one, the city (Los Angeles $18.42 and San Francisco $19.61 from July 1, 2026; San Jose $18.45, San Diego $17.75, Oakland $17.34 and Denver $19.29 for 2026). A rate below it holds the export, with what the person would be short this period. You can raise the rate with one tap or pay as entered, for example for a worker the minimum does not cover. Under federal rules we only know the federal minimum; your own state or city may set a higher one.

Time clock rounding

Rounding to the nearest 5, 6 or 15 minutes is allowed when it evens out over time (29 CFR 785.48). Rounding clock-ins up and clock-outs down only ever favors the employer, so when you pick it, each person's cost against the exact punches is shown with a dollar amount. In California we round only the first clock-in and the last clock-out of a day and check meal breaks on the exact punches, because the California Supreme Court held in Donohue v. AMN Healthcare (2021) that meal period punches may not be rounded.

California meal break premiums

For each workday over 5 hours, the gaps between work periods are checked as meals. A gap of 30 minutes or more is a meal. The first must start before 5 hours of work are done; on a day over 10 hours, a second must start before 10 hours are done. If a meal is missing, short or late, one premium of one hour at the regular rate is owed, at most one a day (Labor Code 512 and 226.7).

A waiver is only applied where the law allows it: the first meal on a day of 6 hours or less, or the second on a day of 12 hours or less when the first was taken. We never assume a waiver exists. On the free calculator you tick it yourself; in Run payroll each flagged day has a Waived button.

Missed clock-outs

In Run payroll, a day is flagged as a probable missed punch when it has an odd number of punches, when it spans more than 14 hours, or when it runs 5 or more hours longer than the person's usual day that week. The flag shows what the day would pay as stamped and what it would pay with the person's usual end time, so the owner sees the dollar difference before deciding. Payroll stays on hold until each flag is fixed or accepted.

Reading punch card photos

Photos are read by two AI models, independently. Claude Opus 5.5 reads every card cell by cell and says how sure it is of each time. Claude Haiku 5.5 reads the same photo again on its own. A cell turns amber when the first model is unsure or the two disagree, and nothing is exported while a cell is amber. Tap an amber cell and you see that part of the photo next to the time, so checking it takes a second.

Two reading rules came out of testing. A handwritten hour that could be 1, 10, 11 or 12 is amber unless the digits are unmistakable. And a time whose am or pm was worked out from another unsure time is amber too.

How well it reads. Before building this, we tested the reading on 30 punch cards: 15 stamped by a time clock and 15 written by hand, photographed tilted, in dim light, blurred and compressed. All 640 cells were either read right or marked amber, and no wrong time was shown as sure. About 1 cell in 10 on handwritten cards was amber. These were test cards we made, with handwriting from fonts, not real cards from a real shop. Real cards fold, fade and get coffee on them, so we will publish a number for real cards once enough have gone through the same check.

Photos are read in memory and never written to disk on our servers. We keep the punches that were read, not the photo. Your browser keeps the photo until you close the page, so you can see the crops.

How we test

Every rule has tests built from worked examples, run on every change to the code. They include the week above ($839.25), a California week with a 7th day, a 13 hour day with double time, three kinds of meal premium, a waived meal, and a missed clock-out. The calculator in your browser and the payroll engine on the server are checked against the same examples, so they cannot drift apart.

What this tool does not check

• Rest breaks. Paid 10 minute breaks are not punched, so a card cannot show them.
• The regular rate. Overtime and premiums use the hourly rate you enter. Bonuses, commissions and shift differentials that raise the regular rate are not added for you.
• Exemptions. Whether a job is exempt from overtime, or covered by a special wage order, is not decided here.
• Other states' daily rules and local laws, tips, holiday pay and split shift premiums.
• Payroll itself. We do not withhold taxes, file anything or pay anyone. The files go into your payroll provider.

This is a calculator and a checklist, not legal or tax advice. If a question decides real money, ask your state labor department or an employment lawyer. To add up a week now, open the time card calculator.