Use of the Forecast Function for Predicting Future Sales

[FireandRain]

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:

[TABLE="width: 628"]
<tbody>[TR]
[TD]SKU[/TD]
[TD]Jan-17[/TD]
[TD]Feb-17[/TD]
[TD]Mar-17[/TD]
[TD]Apr-17[/TD]
[TD]May-17[/TD]
[TD]Jun-17[/TD]
[TD]Jul-17[/TD]
[TD]Aug-17[/TD]
[TD]Sep-17[/TD]
[/TR]
[TR]
[TD="align: right"]1[/TD]
[TD="align: right"]1,111[/TD]
[TD="align: right"]2,222[/TD]
[TD="align: right"]3,333[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]2,222[/TD]
[TD="align: right"]3,333[/TD]
[TD="align: right"]4,444[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]3,333[/TD]
[TD="align: right"]4,444[/TD]
[TD="align: right"]5,555[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]4,444[/TD]
[TD="align: right"]5,555[/TD]
[TD="align: right"]6,666[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]5,555[/TD]
[TD="align: right"]6,666[/TD]
[TD="align: right"]7,777[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]6,666[/TD]
[TD="align: right"]7,777[/TD]
[TD="align: right"]8,888[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]7,777[/TD]
[TD="align: right"]8,888[/TD]
[TD="align: right"]9,999[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
</tbody>[/TABLE]

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

[TABLE="width: 771"]
<tbody>[TR]
[TD]SKU[/TD]
[TD]Jan-17[/TD]
[TD]Feb-17[/TD]
[TD]Mar-17[/TD]
[TD]Apr-17[/TD]
[TD]May-17[/TD]
[TD]Jun-17[/TD]
[TD]Jul-17[/TD]
[TD]Aug-17[/TD]
[TD]Sep-17[/TD]
[/TR]
[TR]
[TD="align: right"]1[/TD]
[TD="align: right"]1,111[/TD]
[TD="align: right"]2,222[/TD]
[TD="align: right"]3,333[/TD]
[TD="align: right"]4480[/TD]
[TD="align: right"]5646[/TD]
[TD="align: right"]6775[/TD]
[TD="align: right"]7942[/TD]
[TD="align: right"]9108[/TD]
[TD="align: right"]10237[/TD]
[/TR]
[TR]
[TD="align: right"]2[/TD]
[TD="align: right"]2,222[/TD]
[TD="align: right"]3,333[/TD]
[TD="align: right"]4,444[/TD]
[TD="align: right"]5591[/TD]
[TD="align: right"]6757[/TD]
[TD="align: right"]7886[/TD]
[TD="align: right"]9053[/TD]
[TD="align: right"]10219[/TD]
[TD="align: right"]11348[/TD]
[/TR]
[TR]
[TD="align: right"]3[/TD]
[TD="align: right"]3,333[/TD]
[TD="align: right"]4,444[/TD]
[TD="align: right"]5,555[/TD]
[TD="align: right"]6702[/TD]
[TD="align: right"]7868[/TD]
[TD="align: right"]8997[/TD]
[TD="align: right"]10164[/TD]
[TD="align: right"]11330[/TD]
[TD="align: right"]12459[/TD]
[/TR]
[TR]
[TD="align: right"]4[/TD]
[TD="align: right"]4,444[/TD]
[TD="align: right"]5,555[/TD]
[TD="align: right"]6,666[/TD]
[TD="align: right"]7813[/TD]
[TD="align: right"]8979[/TD]
[TD="align: right"]10108[/TD]
[TD="align: right"]11275[/TD]
[TD="align: right"]12441[/TD]
[TD="align: right"]13570[/TD]
[/TR]
[TR]
[TD="align: right"]6[/TD]
[TD="align: right"]5,555[/TD]
[TD="align: right"]6,666[/TD]
[TD="align: right"]7,777[/TD]
[TD="align: right"]8924[/TD]
[TD="align: right"]10090[/TD]
[TD="align: right"]11219[/TD]
[TD="align: right"]12386[/TD]
[TD="align: right"]13552[/TD]
[TD="align: right"]14681[/TD]
[/TR]
[TR]
[TD="align: right"]7[/TD]
[TD="align: right"]6,666[/TD]
[TD="align: right"]7,777[/TD]
[TD="align: right"]8,888[/TD]
[TD="align: right"]10035[/TD]
[TD="align: right"]11201[/TD]
[TD="align: right"]12330[/TD]
[TD="align: right"]13497[/TD]
[TD="align: right"]14663[/TD]
[TD="align: right"]15792[/TD]
[/TR]
[TR]
[TD="align: right"]8[/TD]
[TD="align: right"]7,777[/TD]
[TD="align: right"]8,888[/TD]
[TD="align: right"]9,999[/TD]
[TD="align: right"]11146[/TD]
[TD="align: right"]12312[/TD]
[TD="align: right"]13441[/TD]
[TD="align: right"]14608[/TD]
[TD="align: right"]15774[/TD]
[TD="align: right"]16903[/TD]
[/TR]
</tbody>[/TABLE]


These are the formulas behind the numbers:

[TABLE="width: 2233"]
<tbody>[TR]
[TD]SKU[/TD]
[TD]42766[/TD]
[TD]=+EOMONTH(N2,1)[/TD]
[TD]=+EOMONTH(O2,1)[/TD]
[TD]=+EOMONTH(P2,1)[/TD]
[TD]=+EOMONTH(Q2,1)[/TD]
[TD]=+EOMONTH(R2,1)[/TD]
[TD]=+EOMONTH(S2,1)[/TD]
[TD]=+EOMONTH(T2,1)[/TD]
[TD]=+EOMONTH(U2,1)[/TD]
[/TR]
[TR]
[TD]1[/TD]
[TD]1111[/TD]
[TD]2222[/TD]
[TD]3333[/TD]
[TD]=FORECAST($Q$2,N3:P3,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N3:$P3,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N3:$P3,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N3:$P3,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N3:$P3,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N3:$P3,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]2[/TD]
[TD]2222[/TD]
[TD]3333[/TD]
[TD]4444[/TD]
[TD]=FORECAST($Q$2,N4:P4,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N4:$P4,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N4:$P4,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N4:$P4,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N4:$P4,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N4:$P4,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]3[/TD]
[TD]3333[/TD]
[TD]4444[/TD]
[TD]5555[/TD]
[TD]=FORECAST($Q$2,N5:P5,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N5:$P5,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N5:$P5,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N5:$P5,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N5:$P5,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N5:$P5,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]4[/TD]
[TD]4444[/TD]
[TD]5555[/TD]
[TD]6666[/TD]
[TD]=FORECAST($Q$2,N6:P6,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N6:$P6,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N6:$P6,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N6:$P6,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N6:$P6,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N6:$P6,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]6[/TD]
[TD]5555[/TD]
[TD]6666[/TD]
[TD]7777[/TD]
[TD]=FORECAST($Q$2,N7:P7,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N7:$P7,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N7:$P7,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N7:$P7,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N7:$P7,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N7:$P7,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]7[/TD]
[TD]6666[/TD]
[TD]7777[/TD]
[TD]8888[/TD]
[TD]=FORECAST($Q$2,N8:P8,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N8:$P8,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N8:$P8,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N8:$P8,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N8:$P8,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N8:$P8,$N$2:$<wbr>P$2)[/TD]
[/TR]
[TR]
[TD]8[/TD]
[TD]7777[/TD]
[TD]8888[/TD]
[TD]9999[/TD]
[TD]=FORECAST($Q$2,N9:P9,$N$2:$P$<wbr>2)[/TD]
[TD]=FORECAST($R$2,$N9:$P9,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($S$2,$N9:$P9,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($T$2,$N9:$P9,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($U$2,$N9:$P9,$N$2:$<wbr>P$2)[/TD]
[TD]=FORECAST($V$2,$N9:$P9,$N$2:$<wbr>P$2)[/TD]
[/TR]
</tbody>[/TABLE]

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!