Calcolatrice ora
The detailed guide below is currently available in English.
Time math without the base-60 headache
Clock arithmetic is awkward because minutes carry 60 seconds and hours carry 60 minutes, so the column-borrowing habits from decimal math lead you astray. This calculator converts every input to seconds first, does the addition or subtraction in plain whole numbers, and then rebuilds the H:MM:SS display. That means 1:45:00 plus 0:30:00 correctly becomes 2:15:00, not 1:75:00.
Adding up a list of durations
The list tab is built for timesheets, workout logs, and media editing. Paste or type one duration per line, using H:MM:SS when you need seconds and H:MM when you do not; blank lines are ignored. Each line is validated, and if one cannot be read you will be told exactly which line to fix rather than getting a silently wrong total.
Reading the decimal result
Besides the H:MM:SS total, the calculator shows the same duration as decimal hours and minutes. Decimal hours (for example, 2.26 instead of 2:15:30) are what payroll systems and spreadsheets usually expect, so you can multiply directly by an hourly rate without extra conversion steps.
Domande frequenti
What does a negative result mean?
On the add-or-subtract tab, subtracting a larger duration from a smaller one gives a negative total, displayed with a minus sign. You can read it as the shortfall between the two durations.
Can I enter minutes only, like 90:00?
Yes — in the list tab, H:MM always means hours then minutes, so 90:00 means ninety hours. If you mean 90 minutes, enter 1:30 or 1:30:00 instead.
Why does my line count as invalid?
Each line must look like H:MM or H:MM:SS with minutes and seconds between 0 and 59. Entries such as 1:75 or plain numbers like 45 are rejected so that typos cannot quietly distort the total.