# Use of the Forecast Function for Predicting Future Sales

#### FireandRain

##### New Member
Hello,

I am a total newbie at forecasting and have a question about the forecasting function.

I have three months worth of sales data for 8 SKUs. I need to predict the next six months of sales for these SKUs. Would the =FORECAST(x, known_y's, known_x's) function work for me here?

Here's the set up I have with some dummy numbers. So I need to predict April to Sept-17 sales data:

 SKU Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 1 1,111 2,222 3,333 2 2,222 3,333 4,444 3 3,333 4,444 5,555 4 4,444 5,555 6,666 6 5,555 6,666 7,777 7 6,666 7,777 8,888 8 7,777 8,888 9,999

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I used the =FORECAST(x, known_y's, known_x's) function to get the following answers:

 SKU Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 1 1,111 2,222 3,333 4480 5646 6775 7942 9108 10237 2 2,222 3,333 4,444 5591 6757 7886 9053 10219 11348 3 3,333 4,444 5,555 6702 7868 8997 10164 11330 12459 4 4,444 5,555 6,666 7813 8979 10108 11275 12441 13570 6 5,555 6,666 7,777 8924 10090 11219 12386 13552 14681 7 6,666 7,777 8,888 10035 11201 12330 13497 14663 15792 8 7,777 8,888 9,999 11146 12312 13441 14608 15774 16903

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These are the formulas behind the numbers:

 SKU 42766 =+EOMONTH(N2,1) =+EOMONTH(O2,1) =+EOMONTH(P2,1) =+EOMONTH(Q2,1) =+EOMONTH(R2,1) =+EOMONTH(S2,1) =+EOMONTH(T2,1) =+EOMONTH(U2,1) 1 1111 2222 3333 =FORECAST(\$Q\$2,N3:P3,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N3:\$P3,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N3:\$P3,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N3:\$P3,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N3:\$P3,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N3:\$P3,\$N\$2:\$P\$2) 2 2222 3333 4444 =FORECAST(\$Q\$2,N4:P4,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N4:\$P4,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N4:\$P4,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N4:\$P4,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N4:\$P4,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N4:\$P4,\$N\$2:\$P\$2) 3 3333 4444 5555 =FORECAST(\$Q\$2,N5:P5,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N5:\$P5,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N5:\$P5,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N5:\$P5,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N5:\$P5,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N5:\$P5,\$N\$2:\$P\$2) 4 4444 5555 6666 =FORECAST(\$Q\$2,N6:P6,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N6:\$P6,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N6:\$P6,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N6:\$P6,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N6:\$P6,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N6:\$P6,\$N\$2:\$P\$2) 6 5555 6666 7777 =FORECAST(\$Q\$2,N7:P7,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N7:\$P7,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N7:\$P7,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N7:\$P7,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N7:\$P7,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N7:\$P7,\$N\$2:\$P\$2) 7 6666 7777 8888 =FORECAST(\$Q\$2,N8:P8,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N8:\$P8,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N8:\$P8,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N8:\$P8,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N8:\$P8,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N8:\$P8,\$N\$2:\$P\$2) 8 7777 8888 9999 =FORECAST(\$Q\$2,N9:P9,\$N\$2:\$P\$2) =FORECAST(\$R\$2,\$N9:\$P9,\$N\$2:\$P\$2) =FORECAST(\$S\$2,\$N9:\$P9,\$N\$2:\$P\$2) =FORECAST(\$T\$2,\$N9:\$P9,\$N\$2:\$P\$2) =FORECAST(\$U\$2,\$N9:\$P9,\$N\$2:\$P\$2) =FORECAST(\$V\$2,\$N9:\$P9,\$N\$2:\$P\$2)

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Is this an appropriate way to use the forecast function? Is my use of the month in question the right "x" (cells Q2, R2,S2, T2,U2, V2) and the months I have data for the right "known_x's" (N2:P2)?

I can send this excel sheet if that is helpful. I REALLY appreciate your help! Thank you!

### Excel Facts

How to total the visible cells?
From the first blank cell below a filtered data set, press Alt+=. Instead of SUM, you will get SUBTOTAL(9,)