rounding minutes down

[Del117]

Hi
I'm looking for some help with a bit of code for a user form people enter start time and end time and im trying to get a macro to take one from the other which all works fine, converts to a decimal also works, but, what I'm trying to do is to round time down when its 00:03 it should be 0.0, 00:09 should be rounded down to 0.1 and so on, here is an example:
00:01 0.0 this is correct,
00:02 0.0 this is correct,
00:03 0.1 this should be 0.0
00:04 0.1 this is correct,
00:05 0.1 this is correct,
00:06 0.1 this is correct,
00:07 0.1 this is correct,
00:08 0.1 this is correct,
00:09 0.2 this should be 0.1
etc etc......

I have used the round down function but then 00:04 also gets rounded down.
Anybody?

[shg]

What do the decimals values represent?

[Del117]

it's basically just a decimal of an hour so 0.3 is 18 minutes,it is to bill people the problem is we bill people to the nearest o.1 of an hour but we round 00:03 down to 0 so they dont pay 00:04 gets rounded up I have the same problem when its 00:09 and so on, hope this clears things up.

[shg]

=round(24*(a1-"0:01"), 1)

[Del117]

thanks I think thats it, Ill test and report back