Use forward-looking concept to build the user defined functions in Excel for calculating inventory days & inventory balance (forecast). You should download the file, otherwise, you cannot view clearly the content and use the functions

1. Target Inventory Week Illustration
Week1 Week2 Week3 Week4 Week5 Week6 Week7
Demand
Inventory Holding 100
Goods to receive 100
Order to place 100 200 300

2. Week8 Week9 Week10 Week11 Week12
100 200 300
300 600
200 300

3. Illustration of Target Inventory Weeks MOQ 550
Target Weeks 3.0
Week Opening Purchase Sales Closing Opening Purchase Sales
0 #VALUE!
1 #VALUE! #VALUE! 776 #VALUE! #VALUE! #VALUE! 776
2 #VALUE! #VALUE! 728 #VALUE! #VALUE! #VALUE! 728
3 #VALUE! #VALUE! 432 #VALUE! #VALUE! #VALUE! 432
4 #VALUE! #VALUE! 496 #VALUE! #VALUE! #VALUE! 496
5 #VALUE! #VALUE! 696 #VALUE! #VALUE! #VALUE! 696
6 #VALUE! #VALUE! 291 #VALUE! #VALUE! #VALUE! 291
7 #VALUE! #VALUE! 300 #VALUE! #VALUE! #VALUE! 300
8 #VALUE! #VALUE! 266 #VALUE! #VALUE! #VALUE! 266
9 #VALUE! #VALUE! 236 #VALUE! #VALUE! #VALUE! 236
10 #VALUE! #VALUE! 288 #VALUE! #VALUE! #VALUE! 288
11 #VALUE! #VALUE! 296 #VALUE! #VALUE! #VALUE! 296
12 #VALUE! #VALUE! 721 #VALUE! #VALUE! #VALUE! 721
13 #VALUE! #VALUE! 461 #VALUE! #VALUE! #VALUE! 461
14 #VALUE! #VALUE! 300 #VALUE! 300
15 #VALUE! #VALUE! 971 #VALUE! 971
16 #VALUE! #VALUE! 646 #VALUE! 646
17 #VALUE! #VALUE! 946 #VALUE! 946
18 #VALUE! #VALUE! 602 #VALUE! 602
19 #VALUE! #VALUE! 881 #VALUE! 881
20 #VALUE! #VALUE! 303 303
21 - 633 633 633
22 - 564 564 564
23 - 344 344 344
24 - 633 633 633
25 - 583 583 583
26 - 477 477 477
27 - 848 848 848
28 - 501 501 501
29 - 135 135 135
30 - 136 136 136
31 300 300
32 438 438
33 242 242
34 666 666
35 482 482
36 500 500

4. Stock balance
Principal Additional
#VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE! #VALUE!
#VALUE!
#VALUE!
#VALUE!
#VALUE!
#VALUE!
#VALUE!

5. xToday 1/25/2010 Target Weeks 3 LeadTime 14
Existing Pull in /
Week Opening Sales Closing Purchase P/O Qty (Push out)
0 #VALUE!
1 #VALUE! 776 #VALUE! #VALUE! 300 #VALUE!
2 #VALUE! 728 #VALUE! #VALUE! 250 #VALUE!
3 #VALUE! 432 #VALUE! #VALUE! 350 #VALUE!
4 #VALUE! 496 #VALUE! #VALUE! 400 #VALUE!
5 #VALUE! 696 #VALUE! #VALUE! 300 #VALUE!
6 #VALUE! 291 #VALUE! #VALUE! 500 #VALUE!
7 #VALUE! 300 #VALUE! #VALUE! 500 #VALUE!
8 #VALUE! 266 #VALUE! #VALUE! 700 #VALUE!
9 #VALUE! 236 #VALUE! #VALUE! 200 #VALUE!
10 #VALUE! 288 #VALUE! #VALUE! 600 #VALUE!
11 #VALUE! 296 #VALUE! #VALUE! 1,000 #VALUE!
12 #VALUE! 721 #VALUE! #VALUE! 1,200 #VALUE!
13 #VALUE! 461 #VALUE! #VALUE! 700 #VALUE!
14 #VALUE! 300 #VALUE! #VALUE! 600 #VALUE!
15 #VALUE! 971 #VALUE! #VALUE! 200 #VALUE!
16 #VALUE! 646 #VALUE! #VALUE! 700 #VALUE!
17 #VALUE! 946 #VALUE! #VALUE! 600 #VALUE!
18 #VALUE! 602 #VALUE! #VALUE! 500 #VALUE!
19 #VALUE! 881 #VALUE! #VALUE! 500 #VALUE!
20 #VALUE! 303 #VALUE! #VALUE! 750 #VALUE!
21 #VALUE! 633 #VALUE! #VALUE! 550 #VALUE!
22 #VALUE! 564 #VALUE! #VALUE! 700 #VALUE!
23 #VALUE! 344 #VALUE! #VALUE! 500 #VALUE!
24 #VALUE! 633 #VALUE! #VALUE! 300 #VALUE!
25 #VALUE! 583 #VALUE! #VALUE! 200 #VALUE!
26 #VALUE! 477 #VALUE! #VALUE! 400 #VALUE!
27 #VALUE! 848 #VALUE! #VALUE! 300 #VALUE!
28 #VALUE! 501 #VALUE! #VALUE! 300 #VALUE!
29 #VALUE! 135 #VALUE! #VALUE! 600 #VALUE!
30 #VALUE! 136 #VALUE! #VALUE! 500 #VALUE!
31 300
32 438
33 242
34 666
35 482
36 500

6. 1/18/2010
1/25/2010
2/1/2010
2/8/2010
2/15/2010
2/22/2010
3/1/2010
3/8/2010
3/15/2010
3/22/2010
3/29/2010
4/5/2010
4/12/2010
4/19/2010
4/26/2010
5/3/2010
5/10/2010
5/17/2010
5/24/2010
5/31/2010
6/7/2010
6/14/2010
6/21/2010
6/28/2010
7/5/2010
7/12/2010
7/19/2010
7/26/2010
8/2/2010
8/9/2010

7. Dec-03
Stock Value 8,500
Stock Days #VALUE! days
Jan-04 Feb-04 Mar-04 Apr-04
Cost of Goods Sold 3,253 1,540 3,548 4,500
Stock Value 8,500
Cost of Goods Sold Days
Jan-04 3,253 30
--------------
5,247
Feb-04 1,540 30
--------------
3,707
Mar-04 3,548 30
--------------
159
Apr-04 4,500 1
-------------- ---------
- 91

8. Dec-03
Stock Value #VALUE!
Stock Days 90 days
Jan-04 Feb-04 Mar-04 Apr-04
Cost of Goods Sold 3,253 1,540 3,548 4,500

9. Stock Days 45 days
Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04
Cost of Goods Sold 4,750 3,253 2,540 3,548 4,500 5,000 6,150
(qty or cost)
Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04
Inventory ### ### ### ### ### ### ### ###
Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04
Purchase 3,000 ### ### ### ### ### ### ###
Opening + Purchase - Cost of Goods Sold = Closing
=====> Purchase = Closing + Cost of Goods Sold - Opening
Creditors Day 75 days
Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04
Accounts Payable ### ### ### ### ### ###
Debtors Day 45 days
Cash Cycle Stock Days Debtors Days
Cash
Creditors Days Days

10. Jul-04 Aug-04 Sep-04
5,500 4,700 6,700