Ok so i admit it...i love tracking my shaving products. I’m not full blown spreadsheet (yet) but i track the price and start/end dates of everything i buy. Recently i had an interesting thought and was wondering if my math actually holds up. For that, i relying on the math wizards here at B&B (i’m looking at you @ShavingByTheNumbers!) to help me out. So recently i finished up a 16 oz bottle of witch hazel which i use after ever shave. The bottle lasted from 03/14/18 to 02/20/20. That’s 708 days best i can figure. Because i use the same amount of witch hazel as i do aftershave, i thought that perhaps i can figure out how long my current aftershave supply will last! So i counted up the ounces of my 19 bottles of aftershave and came up with 95.84oz. So, given that it took me 708 days to use 16 oz of witch hazel, how long will it take me to use 95.84oz of aftershaves assuming the same rate of use for both? I came up with a figure of 11.619 years. Does that sound correct? Thanks for the help!
A math problem for all you spreadsheet fans!
- Thread starter Macduff
- Start date
(95.84/16)*708/365=11.619
Some adjustment would need to be made for leap years.
It helps to weigh a new bottle so you can tell how much you used by weight. When you get an empty bottle, you can convert Fluid oz. to grams.
I calculate on a per use basis. For instance, I've shaved 398 times and used aftershave 156 times. I've used 15 grams of AS. There are 147 in the bottle. So, I can get 1,528 shaves/bottle.
I have three bottles, so, I have plenty for a 10-year "desert island" restraint.
Some adjustment would need to be made for leap years.
It helps to weigh a new bottle so you can tell how much you used by weight. When you get an empty bottle, you can convert Fluid oz. to grams.
I calculate on a per use basis. For instance, I've shaved 398 times and used aftershave 156 times. I've used 15 grams of AS. There are 147 in the bottle. So, I can get 1,528 shaves/bottle.
I have three bottles, so, I have plenty for a 10-year "desert island" restraint.
Last edited:
As Gary indicated, you need to account for leap years if you want to be exact. Technically, a year is 365.2422 days, so by using the average of 365 days, you are off by 0.066%, but since none of your measurements are quite that precise, using 365 days is fine. Both of you were able to get the result without resorting to a spreadsheet. Well done.
As usual, we disagree.
For someone who shaves every day, there are 366 days in a leap year and 365 in the other years. In the OP's problem, there is an extra shave in years 1, 5 and 9. Even though the problem is created in the leap years, the days would be counted against the last year.So, for a WAG, subtract 3/365 from 11.619 to get 11.611.
that math is all fine and dandy til the day you let Charles Bronson use your bathroom and 11 years worth of aftershave pours down his head, back, and chest in 11 seconds
Now you have the beginnings of a Navy Quartermaster game.
I have an excel log where I track most of the items I use every day. The CountIf function is handy:
=CountIF(B$3:b5000,"williams")
If I copy that down a column, it logs how many times I've used Williams. You can fancy it up to leave the cell blank if you didn't shave on a day.
Here is the summary for today for the number of shaving days in a row I've used Williams:
=CountIF(B$3:b5000,"williams")
If I copy that down a column, it logs how many times I've used Williams. You can fancy it up to leave the cell blank if you didn't shave on a day.
Here is the summary for today for the number of shaving days in a row I've used Williams:
As usual, we disagree.
So, for a WAG, subtract 3/365 from 11.619 to get 11.611.
If you take your equation and divide by 365.2422 rather than 365, you will get an answer of 11.611 which is the same as you got the second time around. Thus, there is no disagreement. My point is that the difference between 11.619 and 11.611 is less than the precision in measurement of the amount of aftershave used per day, so it does not really matter in the grand scheme of things.
I agree it doesn't matter.
- Thread starter
- #12
that math is all fine and dandy til the day you let Charles Bronson use your bathroom and 11 years worth of aftershave pours down his head, back, and chest in 11 seconds
Honestly haven’t laughed that hard at a post here at B&B ever!
That one was pure gold! And thanks for everyone else checking my math. I was just looking for a rough number since it’s pretty imprecise anyway. Anyone care to calculate how many shaves i’d get if i shave every other day?!Honestly haven’t laughed that hard at a post here at B&B ever!
I have a paywall for that.
Honestly haven’t laughed that hard at a post here at B&B ever!
If you want to extend the life of your aftershave, you could do what I do and only use it on special occasions. I use witch hazel after every shave, but I probably use aftershave or cologne about once every month or two.
- Thread starter
- #15
I had considered it but i’m more of the enjoy it destroy it mentality hahaha. I was mostly curious how long all those bottles would actually last since i went on quite the buying spree last year. That and blades are the areas of shaving i like a lot of variety. I’ve been using aftershaves since 03/18 so that means i have about 9 and a half years left till i run out. I think what i’ll probably do is try to use them at a roughly equal rate so i maintain variety throughout the whole time. We’ll see how that goes though.
Thanks for posting. I have a spreadsheet which covers:
I have kept this record for five years and have had my wife make comments about being compulsive, etc. about keeping these records. I just showed her what you are doing and she now realizes I am not alone and that there are others more compulsive than me!
| Date | Soap | Razor | Brush | Blade | Blade #shaves | Comments |
I have kept this record for five years and have had my wife make comments about being compulsive, etc. about keeping these records. I just showed her what you are doing and she now realizes I am not alone and that there are others more compulsive than me!
- Thread starter
- #17
Thanks for posting. I have a spreadsheet which covers:
Date Soap Razor Brush Blade Blade #shaves Comments
I have kept this record for five years and have had my wife make comments about being compulsive, etc. about keeping these records. I just showed her what you are doing and she now realizes I am not alone and that there are others more compulsive than me!
Glad i could help hahaha. Is it a bit neurotic? Perhaps. But to me, you and many others it’s genuinely fun and interesting! I’m by no means a math guy but something about tracking this stuff and calculating the longevity is almost compulsive.
rbscebu
Girls call me Makaluod
Don't forget that every hundred year (1900, 2000, etc.) is not a leap year. Luckily the exercise in this topic does not extend over a hundred year.
They didn't skip leap year in 2000.
rbscebu
Girls call me Makaluod
You are correct. I was wrong. The leap year is skipped every hundred year EXCEPT every thousand year.
