HELP: Inventory vs. COGS for monthly projections

So I know for annual projections inventory can be calculated as (inventory days/365)*COGS. COGS/Inventory is how many times inventory is turned over so it makes sense that annually the COGS will be a lot higher than inventory.

However, I'm a little confused when doing monthly. Say for January 2010 COGS is projected to be 10,000. If we're trying to project inventory based on COGS, and inventory days is 30, should inventory be calculated as (30/360)10,000? Or should it be over # of days in a month: (30/30)10,000? In this case since it takes 30 days to turn over and the # of days in a month is 30, would inventory just equal COGS?

Thanks!

2 Comments
 
Best Response

Ok, well think about it this way. Inventory Turnover Days = Days in Period / Inventory Turnover . Therefore, Inventory Turnover = Days in Period / Inventory Turnover Days. In your case of January, IT = 31 / 30 .

Also we know, IT = COGS/Avg Inventory. Solving for Inventory:

Inventory = COGS / IT ==> Inventory = 10,000 / (31/30) or approximately 10,000

From another angle you could think about it this way... if the company were to do the exact same thing every month, IT, Days Inventory and Inventory should all approximately stay the same, so lets test our method.

For FY 2010 then, Inventory = 10,000 & COGS = 10,000*12 = 120,000 IT = 120,000 / 10,000 = 12 Days inventory = 365 / 12 which is approximately 30 (a little off since we assumed about 30 days in a month, but nonetheless logically correct). Therefore, we can conclude our inventory calculation was accurate.

Hope this helps.

Jack: They’re all former investment bankers who were laid off from that economic crisis that Nancy Pelosi caused. They have zero real world skills, but God they work hard. -30 Rock
 

Similique pariatur earum tenetur voluptatem. Laboriosam tempora et corrupti perspiciatis nulla maiores blanditiis. Fugiat eligendi officia iusto ad ut id ut laborum. Doloremque exercitationem et non.

Possimus molestias iure vitae eum repellat. Ut nostrum dolorem doloremque vel expedita.

Career Advancement Opportunities

June 2026 Investment Banking

  • Evercore 01 99.4%
  • Moelis & Company 01 98.9%
  • JPMorgan 01 98.3%
  • Guggenheim Partners 01 97.7%
  • Morgan Stanley 07 97.1%

Overall Employee Satisfaction

June 2026 Investment Banking

  • Moelis & Company No 99.4%
  • Morgan Stanley 02 98.8%
  • Evercore 01 98.3%
  • BMO Capital Markets 12 97.7%
  • Banco Santander 01 97.1%

Professional Growth Opportunities

June 2026 Investment Banking

  • Evercore 01 99.4%
  • Moelis & Company 01 98.9%
  • Morgan Stanley 05 98.3%
  • JPMorgan No 97.7%
  • Goldman Sachs 02 97.1%

Total Avg Compensation

June 2026 Investment Banking

  • Vice President (14) $434
  • Associates (44) $258
  • 3rd+ Year Analyst (8) $210
  • 2nd Year Analyst (22) $179
  • Intern/Summer Associate (13) $156
  • 1st Year Analyst (79) $150
  • Intern/Summer Analyst (73) $101
notes
16 IB Interviews Notes

“... there’s no excuse to not take advantage of the resources out there available to you. Best value for your $ are the...”

Leaderboard

1
redever's picture
redever
99.2
2
kanon's picture
kanon
99.0
3
BankonBanking's picture
BankonBanking
99.0
4
Secyh62's picture
Secyh62
99.0
5
Betsy Massar's picture
Betsy Massar
98.9
6
dosk17's picture
dosk17
98.9
7
DrApeman's picture
DrApeman
98.9
8
GameTheory's picture
GameTheory
98.9
9
CompBanker's picture
CompBanker
98.9
10
bolo up's picture
bolo up
98.8
success
From 10 rejections to 1 dream investment banking internship

“... I believe it was the single biggest reason why I ended up with an offer...”