Deducting breaks in total time cell

[AndyB63UK]

A1 is start time, B1 is finish time, C1 is B1 - A1 to give total time worked that day.
Is there an easy way to auto deduct breaks in C1 as follows?
less than or equal to 9 hours deduct 30 mins break
More than 9 hours deduct 1 hour break
All cells to be 24 hour format without : entered as 0900
Thanks in advance

 

[kvsrinivasamurthy]

In C1

=IF(B1-A1<=9/24,B1-A1-TIMEVALUE("0:30:00"),B1-A1-TIMEVALUE("1:00:00"))

 

[Vintage79]

I use this: =IF(B1="","",(MOD(B1-A1,1))*24) which is useful if a shift goes past midnight and into a new day. But it does require times to be entered with a colon (09:00 etc). It also needs A & B columns formatted as time, and C to be formatted as number.

Perhaps a combination of this and kvsrinivasamurthy's suggestion would be ideal.

 

[AndyB63UK]

Both great ideas but with =IF(B1-A1<=9/24,B1-A1-TIMEVALUE("0:30:00"),B1-A1-TIMEVALUE("1:00:00")) I get ######### in C1 when A1 and B1 are empty.

And =IF(B1="","",(MOD(B1-A1,1))*24) doesn't work, sorry.

I'm on Office 365 Personal on a Windows 10 Laptop.

Maybe I should be more precise;

A B C D E F G H
1 Mon Tue Wed Thu Fri Sat Totals
2 Start time
3 Finish time
4 Total less Break

Hope that makes it clearer, don't now how to paste a screen shot.

 

[AndyB63UK]

Sorted with a combination of both.

=IF(B1="","",IF(B1-A1<=9/24,B1-A1-TIMEVALUE("0:30:00"),B1-A10-TIMEVALUE("1:00:00")))

Many thanks guys

 

[Vintage79]

So, the start time is in A2, and finish time in A3 for Monday?