tracking weight loss

I'm looking for a formula I can use in excel that will track weight loss. I want to take the current week's weight and have it subtracted from the original weight. The spreadsheet will cover 52 weeks of weigh ins. How can I create a formula that will use the last weight entry compared to the original weight entry every week? Any help is appreciated. Thank you.

Sorry Dave...how do i complete the rest of the formula?

OK,

so you put the original weight in A1,

Then in A2 to A52 you put the relative week's weight

In B2 enter

=$A$1-B1

which will give you the loss of weight for that week.

Copy B2 and paste it into B3:B52

Is there a way to do that so it tracks to date instead of having it track for each week? I hope i'm making sense...lol.

So you just want the original weight minus the lastest weight recorded?

Yes...exactly...but I don't want to have to change the formula each week for the new cell with the new weight in it.

Gotcha!!

The last value in a column can be got like this

=OFFSET(A1,COUNT(A:A)-1,0)

for column A.

So, if the original weight is in A1, and all the other weights are being entered below it,

=A1-OFFSET(A1,COUNT(A:A)-1,0)

will giv you the weight loss to date

Awesome...it worked...thank you so much for all of your help!