Calculating time

[regs01]

Those two approaches gives me different result
time(3:30−2:15) to time = 20:53:56,25
(time(3:30)−time(2:15)) to time = 20:55:31,25

While those two giving me correct result
3.5 − 2.25 to time = 1:15
3:30 − 2:15 to time = 1:15

Is this how time function is supposed to work or I misunderstood something or misused it?

[regs01]

And more
3:30 − 2:15 to min = 0,02083333333 min
even this is same
(3:30:00.0 − 2:15:00.0) to min = 0,02083333333 min

Shouldn't result be 75 min?

[hanna-kn]

The time() always function always returns the current time and does not accept any argument.

3:30 is interpreted as a sexagesimal number, which equals 3.5 (and 2:15 equals 2.25). When an expression without any unit is converted to a unit, the initial expression is interpreted as using the corresponding SI base unit (the SI base unit for time is s), thus the expression 3:30 − 2:15 to min is interpreted as (3.5 − 2.25) s to min. I understand that this behaviour is confusing in this case.

[regs01]

So it's just this to use 3:30 − 2:15 to time = 1:15 ?

Made it with 03:30 h − 02:15 h to min = 75 min

[aljustiet]

Is there now for time?

[aljustiet]

I can do this:

21:00 - time to time. But, it's verbose.

[hanna-kn]

If output format with units is acceptable:
21h-timeh
today+21h-now

Alternatively the command base time can be used before multiple calculations, instead of to time (which however can be slightly shortened to ->time).