Both dates are read in this zone, so a daylight-saving change between them counts.
The "Now" buttons work once the page has finished loading.
Time between
1 month, 1 day, 8 hours and 30 minutes
Sat 31 Jan 2026, 09:00 to Sun 1 Mar 2026, 17:30
Dates in the range
Calendar days
29
Business days
20
Monday to Friday, no public holidays
Elapsed time
Days
29.35
Weeks
4.19
Hours
704.5
Minutes
42,270
Seconds
2,536,200
Milliseconds
2,536,200,000
As a duration
ISO 8601
P1M1DT8H30M
Java Duration
PT704H30M
Compact
1mo 1d 8h 30m
How this one works
The difference between two dates is given two ways, because both are useful and they disagree. The sentence at the top counts calendar units: years, months and days as a person would say them, which is how Java's Period and Python's relativedelta count. Elapsed time counts the hours that pass, which is what a deadline or a bill runs on.
Adding a duration follows the same split: months and days move the calendar (so one month after 31 January is 28 February, and a day later is the same time tomorrow even if the clocks changed overnight), while hours, minutes and seconds are added as exact elapsed time. Half a day is 12 hours; half a month has no calendar meaning, so it is counted as 15 days and the result says so.
Calendar and business days count dates, not hours: from 23:00 one evening to 01:00 the next morning is one calendar day. They count the start date but not the end one, the way "3 days from Monday" lands on Thursday; tick "Count the end date too" for a booking or a leave request, where both ends count. Public holidays are not taken out, because they differ by country and guessing them would be worse than leaving them to you.
Questions
Why do the calendar figure and the elapsed days disagree?
Because months are not a fixed length. From 31 January to 1 March is "1 month and 1 day" on the calendar, but 29 elapsed days in 2026. Neither is wrong. Use the calendar reading for how people talk about it, and elapsed time for arithmetic.
What duration formats are understood?
ISO 8601 (P1Y2M3DT4H5M6S, and P2W for weeks), Java's Duration.toString() including its negative component form (PT-6H-30M), and plain text such as "1d 2h 30m", "90 minutes" or "2 years 6 months".
Does daylight saving affect the result?
Yes, and it is handled. The dates are turned into instants in the zone you choose, so a range that crosses a clock change has 23 or 25 hours in that day. If a date you pick, or a date a calculation lands on, falls in an hour that is skipped or happens twice, the tool says so and says which moment it used.
Are leap years and leap seconds handled?
Leap years, yes: February 2028 has 29 days here. Leap seconds, no: Unix time ignores them, so every minute is 60 seconds, the same assumption your database and language make.