percentage spreadsheet

Please see attached, it's a weight loss spreadsheet for me and some girlfriends.

Note that B10 through K10 for example add up to 7.5037%. But cell K13 is supposed to display that number because it's total weight loss so far divide by starting weight (cell A9)
What am I doing wrong?

How come all weekly percentages don't just add up to total lbs lost so far divided by starting weight? How come those two numbers don't match! Please help!

THANKS!

Hi jennylovespigs,

the formula you were using was incorrect starting cell C11 onwards. I have corrected the formula for you. The use of Cell A9 should have been made static and it would have worked fine.

Do let me know in case of any clarifications.

Cheers!!
Excel-o-ratoR

Percentages don't work that way...

Imagine starting with 1000 and subtracting 10% each time
1000 - 10% = 1000 - 100 = 900
900- 10% = 900 - 90 = 810
810 - 10% = 810 - 81 = 729

Adding %'s would give you 30% but in actuality it is a 27.1% reduction.

Thanks for your revision, but row 13 includes all total weight lost percentage, I think that's what your new formula leads to.

What I want for row 11 is % lost just from the previous week, not from starting weight (cell a9) if I weighed 200 lbs week 2, and I weigh 195 lbs week 3, I want that percentage, not from my starting weight on week 1.

Does this make sense?

But is this mathematically wrong? Should I not assume that adding up weekly percentages weight loss dividing from the weight weighed in from the week before would add up to total percentage weight loss from the starting weight?

SHG, correct, but that is already noted in row 13, I don't want them expressed as a percentage lost from original weight, I want them as a percentage lost just from the weight the week prior.

jenny,
Please see my reply in post number 3 of this thread.

I hoped it was some thing above me I couldn't figure out/fix. Thanks! I'm a blonde, forgive me.