A time card looks simple — clock in, clock out — but turning a week of punches into a correct paycheck involves break deductions, shifts that cross midnight, two different overtime regimes, and rounding policies that are themselves regulated. This guide walks through the math the calculator uses and the rules behind it so you can check a paystub, plan a schedule, or settle a disagreement with confidence.

From punches to decimal hours

Worked time for a shift is simply the clock-out minus the clock-in, minus any unpaid break. The two wrinkles are midnight-crossing and splits. If a shift ends at a time earlier than it began (10 p.m. to 6:30 a.m.), the calculator adds 24 hours so the result is 8.5 hours rather than a nonsensical negative. A split shift — a morning block and an evening block with a long gap — is entered as two in/out pairs that are summed before the break is subtracted.

Payroll then converts hours-and-minutes into decimal hours, because you cannot multiply 7:30 by a dollar rate. The conversion is minutes ÷ 60: 7 h 30 m becomes 7.50 h, 8 h 6 m becomes 8.10 h. The calculator displays both formats for every day and for the week so you can sanity-check either way.

Daily vs. weekly overtime

The federal Fair Labor Standards Act (FLSA) requires overtime — at least 1.5× the regular rate — only for hours worked beyond 40 in a single workweek for non-exempt employees. It has no daily overtime requirement, so under the pure federal rule a 12-hour day followed by three short days may carry no overtime at all if the week stays under 40.

Several states go further. California, Alaska, and Nevada (among others) require daily overtime past 8 hours, and California adds double-time past 12 hours in a day and on the seventh consecutive workday. That is why this tool lets you pick "daily," "weekly," or "both." The "both" setting computes daily overtime first and then checks the weekly 40-hour cap on the remaining regular hours, so a single hour is never paid as overtime twice. Always confirm which rule your state and job classification fall under — exempt salaried roles generally are not entitled to overtime at all.

Rounding rules and their legality

Many employers round clock punches to a tidy increment — the nearest 5, 6 (a tenth of an hour), or 15 minutes. Under longstanding federal guidance (29 CFR 785.48), rounding is permissible only if it is neutral over time — it must not, on average, favor the employer. The well-known "7-minute rule" pairs with 15-minute rounding: punches 1–7 minutes past a quarter-hour round down, 8–14 round up. A policy that always rounds down (against the worker) has been found unlawful in several cases, and California courts have grown skeptical of rounding altogether now that electronic timekeeping can capture exact minutes. This calculator offers none / 5 / 6 / 15-minute rounding so you can mirror your employer's policy and compare it against the exact-minute total.

Limits and when to get help

This calculator is a record-keeping and planning aid, not a payroll system or legal authority. It does not compute taxes, benefit deductions, tipped-wage credits, shift differentials, holiday premiums, meal-penalty pay, or the seventh-consecutive-day rules that some states impose. Overtime exemptions (executive, administrative, professional, outside sales) can change whether any premium is owed at all. If your real paycheck differs from what you expect, or you believe overtime or breaks were handled incorrectly, keep your own records and consult the U.S. Department of Labor Wage and Hour Division or your state labor agency.