It's the rounding at all those decimal places that is causing the
issue...try using the ROUND function on you lookup times, say to 6 decimals
and then wrap the looked up value in a ROUND function too using the same
decimals,like

=VLOOKUP(ROUND(A1,6),Sheet1!$A$1:$B$24,2,FALSE)

Using a little trial and error you will only be losing precision in seconds
or probably milliseconds.

One way at least if that precision is not necessary

--
HTH
Nick Hodge
Microsoft MVP - Excel
Southampton, England
www.nickhodge.co.uk
HIS


"jjhmbh" wrote in
message ...

We have discovered a problem in referencing time using the LOOKUP
function and I haven't been able to resolve it using VLOOKUP or the
INDEX and MATCH combination

The easiest way to demonstrate the problem is to creat a list of times
from 10:00 am to 12:00 pm in 15 minute increments, then copy the list
into the adjacent column and convert that list into the decimal
equivalent. See below for what the list should look like. I expanded
the decimals to the maximum number of decimals.

10:00 0.416666666666667
10:15 0.427083333333333
10:30 0.437500000000000
10:45 0.447916666666667
11:00 0.458333333333333
11:15 0.468750000000000
11:30 0.479166666666667
11:45 0.489583333333333
12:00 0.500000000000000

Now if you write a formula using LOOKUP or VLOOKUP to try to return the
decimal equivalent of a time in the left column. It works fine except
at a few times like 10:45 and 11:30 when it returns the values for
10:30 and 11:15 respectively.

Any help would be appreciated.

Jeff


--
jjhmbh
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