Taking 30 minutes off a time

[Sullster47]

I am working on a time management system and need to deduct 30 minutes for break time. I cannot seem to get it to work any way I have tried. Can someone please help? 

So far, I have got it to work out which paygrade to put the hours in, and if it crosses over into another pay grade (overtime) it works out how many hours to put in that rate, but I need to knock off 30 minutes for break and this is where I am falling down.

Thanks in advance.

[#2]

Hi,

If it is really just about what you have in the subject, then

DateAdd("n","-30", [YourTimeField])

Servus
Karl
************
Access News
Access DevCon

[#3]

I have the start time and the finish time and have then worked out the hours worked. (08:00-16:00 = 8). This is held in another field for ease. I then need to take off x minutes depending on customer.
I have brough through the customers minutes to be deducted.

Set Thisdb = CurrentDb
Set Recs = Thisdb.OpenRecordset("QryCustomersDepotsSingleDepot", dbOpenDynaset)
Set Bookings = Thisdb.OpenRecordset("QryBookingSingleBooking", dbOpenDynaset)
Set UpdateHrs = Thisdb.OpenRecordset("QryTimeDiffUpdate", dbOpenDynaset)


UpdateHrs.MoveFirst
HrsLeft = UpdateHrs!Hrs


Recs.MoveFirst
ThisCustomer = Bookings!BCustomer

Set CDBreak = Thisdb.OpenRecordset("QryCustomerDepotsSingleDepot", dbOpenDynaset)

RateTimeStart = Recs!CDWHRate1Text
RateTimeEnd = Recs!CDWHRate2Text
CDBreak.MoveFirst

BreakTime = CDBreak!CDBreakTimeDed

If BreakTime = "0.5" Then
BreakTimeMins = "00:30"
Dateadd("n",-30,[hrsleft])

Thanks for your help Karl

[#4]

I think I have figured it out now. Thanks for your help.