This online time clock does one job well: punch in when you start, punch out when you stop, and it keeps a running list of the day's segments with a total in both hours and minutes and decimal hours. Everything is stored in your own browser, so there is no account to create and nothing leaves your device. For a whole week at once, use the time card calculator.
Why the total appears twice
Hours worked are read one way and paid another. A shift of 7 hours 45 minutes is written 7:45 on a card but entered as 7.75 in payroll, because minutes are sixtieths rather than hundredths. Getting this wrong is the most common time-card error there is — the decimal converter exists purely to stop it, and converting minutes to decimal hours explains the arithmetic.
What this clock is and is not
It is a personal record: accurate, private and immediate. It is not a payroll system — there is no approval workflow, no multi-employee roster and no export to an accounting package. If you need those, see free time clock versus payroll software for where the line sits.