Hong Kong
Hong Kong Time duration calculator
Enter a span of time as days, hours, minutes and seconds, and it adds them into one clean total, then restates that total in hours, in minutes and in seconds. It is the quick way to answer questions that plain mental arithmetic fumbles: how many minutes is two and a half hours, how many hours is a three-day trip, how many seconds in a 90 minute match. People use it to add up timesheet entries, to convert a video or audio length into seconds for a setting, to total the legs of a journey, or to check a billing block that mixes hours and minutes. There is no calendar or clock involved, so it stays simple: a duration in, the same duration expressed several useful ways out.
Days are counted as 24 hours. Calendar gaps that cross a daylight-saving change can differ by an hour.
How it works
- Fill in any of the four boxes: days, hours, minutes and seconds. Leave the rest at zero.
- The values are added together into a single span of time.
- The headline tile reads the total back in plain language, such as 2 hours, 30 minutes.
- Three more tiles give the same span as a number of hours, of minutes and of seconds for copying into a form or setting.
total seconds = days x 86400 + hours x 3600 + minutes x 60 + seconds
Every entry is converted to seconds using fixed factors: 86,400 seconds in a day, 3,600 in an hour, 60 in a minute. Adding those gives one total in seconds, which is then divided back down to express the same span in whole days, hours, minutes and seconds, and separately as a decimal number of hours or a plain count of minutes.
- days
- whole days, each treated as 24 hours
- hours
- hours to add to the span
- minutes
- minutes to add to the span
- seconds
- seconds to add to the span
Common durations in seconds
| 1 minute | 60 seconds | the base minute |
| 1 hour | 3,600 seconds | a common timeout value |
| 90 minutes | 5,400 seconds | a football match |
| 1 day | 86,400 seconds | counted as 24 hours |
Worked example
A task logged as 2 hours and 30 minutes: the total reads 2 hours, 30 minutes. In other units that is 2.5 hours, 150 minutes, or 9,000 seconds. Add a second entry of 1 hour 45 minutes by raising the hours and minutes, and the running total climbs to 4 hours 15 minutes, or 15,300 seconds.
Key facts
- An hour has 60 minutes, so 1.5 hours is 90 minutes, not 150, a slip decimals often cause.
- A day is 86,400 seconds, which is why long timeouts are often written in those round figures.
- Minutes carry into hours automatically here, so 75 minutes is shown as 1 hour 15 minutes.
- A week is 604,800 seconds, handy when a setting wants a duration in seconds rather than days.
Tips
- To convert decimal hours, split them first: 2.25 hours is 2 hours plus 0.25 of 60, which is 15 minutes.
- When totalling a timesheet, add everything into the minutes box and let the tool carry the hours.
- Copy the seconds figure when a system setting, video tool or script asks for a single duration value.
- For anything spanning real calendar dates, use the date difference tool so daylight saving and month lengths are handled.
Frequently asked questions
Does a day here mean 24 hours?+
Yes. Each day is counted as a flat 24 hours. That is right for durations, though a calendar day that crosses a daylight-saving change can be 23 or 25 hours, which this tool does not try to model.
How do I add several time entries together?+
Put the combined days, hours, minutes and seconds into the boxes. If you are totting up a timesheet, add the hours into the hours box and the minutes into the minutes box; the tool carries 90 minutes up into 1 hour 30 minutes for you.
Why convert a duration into seconds?+
Many settings and scripts expect a single number of seconds rather than a mix of units. A 3 minute clip is 180 seconds, a 1 hour timeout is 3,600 seconds. The seconds tile gives that figure directly.
Can it work out the time between two clock times?+
Not directly; it adds a duration rather than reading a start and end time. For the gap between two dates, the date difference calculator is the right tool. For a span you already know in hours and minutes, this one is quicker.
What is 1.5 hours in minutes?+
Ninety. Enter 1 in hours and 30 in minutes, or 90 straight into the minutes box, and the hours tile confirms 1.5 hours. Decimal hours trip people up because an hour has 60 minutes, not 100.
Things to watch
- Each day is a flat 24 hours, so spans that cross a clock change can be an hour out from a wall-clock reading.
- It adds a duration; it does not subtract one time of day from another, which needs a clock or date tool.
- Very large inputs are summed faithfully but can exceed what a single form field elsewhere will accept.
Last updated: 2026
This is an estimate for general guidance, not financial, tax, legal or medical advice. Figures can change and individual circumstances vary. Always confirm with the official sources listed before making decisions.
Reviewed by Vikas Dulgunde.