Cart Sheets / Free guides
Black Friday inventory planning: a simple stock forecast for small stores
Running out of your best seller on Black Friday is frustrating. Sitting on boxes of unsold stock in January is too. A simple forecast from your own numbers will not be perfect, but it is much better than a guess.
Black Friday is on Friday 27 November 2026 and Cyber Monday on Monday 30 November. This guide shows a forecast you can do in a spreadsheet in an afternoon, with a worked example using made-up numbers.
What you need before you start
- Your normal daily sales for each product over the last 30 to 60 days, in units
- Last year's Black Friday and Cyber Monday sales, if you have them
- The discount you plan to offer on each product (check it still makes money with the free offer margin checker first)
- Your current stock and any stock already on order
- Your supplier's lead time: how many days from placing an order to having stock ready to ship
- The dates your promotion starts and ends
The forecast in four steps
- Find your normal daily sales. Units sold in the last 30 days, divided by 30. Leave out any unusual days, such as a one-off feature or a stockout.
- Pick an uplift. How many times your normal daily sales you expect during the promotion. If you have last year's numbers, divide last year's promo daily sales by last year's normal daily sales. If you do not, pick a cautious number and note that it is a guess.
- Multiply by the length of the promotion. Normal daily sales x uplift x promo days gives the units you expect to sell.
- Add safety stock. A buffer for the forecast being wrong, often 10 to 25 percent of the promo forecast, more for products with unreliable suppliers.
Then subtract what you already have, plus anything on order, to see what you still need to buy.
A worked SAMPLE example (made-up numbers)
A small store sells a candle that normally sells 4 units a day. Last year it sold about three times its normal daily rate during the sale. The store plans a 5-day promotion from Black Friday to Cyber Monday plus one extra day.
SAMPLE: candle stock forecast
| Step | Calculation | Result |
|---|---|---|
| Normal daily sales | 120 units in 30 days / 30 | 4 per day |
| Uplift | From last year | 3x |
| Promo forecast | 4 x 3 x 5 days | 60 units |
| Normal sales before the promo | 4 x 20 days left before 27 Nov | 80 units |
| Safety stock | 20% of 60 | 12 units |
| Total needed | 60 + 80 + 12 | 152 units |
| In stock and on order | Current count | 70 units |
| To order | 152 minus 70 | 82 units |
The SAMPLE numbers are only there to show the method. Your own sales history and uplift will be different, and no forecast can promise what customers will buy.
Work out your reorder-by date
Stock that arrives on 28 November is not much use for a sale that started on the 27th. Work backward:
- Need-by date: when the stock must be on your shelf, ideally a week before Black Friday, so 20 November 2026.
- Lead time: how long your supplier takes, including shipping. Ask them directly, because many suppliers get slower in November.
- Reorder-by date: need-by date minus lead time. If the lead time is 21 days, order by 30 October.
In a spreadsheet: =NeedByDate-LeadTimeDays, then use conditional formatting with =TODAY()>ReorderBy to turn the row red once the date has passed.
Spreadsheet formulas
Put one product per row with these columns: A product, B units sold last 30 days, C uplift, D promo days, E safety stock percent, F current stock plus on order, G lead time in days.
- Normal daily sales (H2):
=B2/30 - Promo forecast (I2):
=H2*C2*D2 - Safety stock (J2):
=ROUNDUP(I2*E2,0) - Units still to order (K2):
=MAX(0,ROUNDUP(I2+J2-F2,0)) - Reorder-by date (L2):
=DATE(2026,11,20)-G2
Add the normal sales before the promotion to the forecast if you need stock for those weeks too, as in the example above.
Decide what to do with each product
Not every product needs a big order. Sort your list into three groups:
- Order more: best sellers with a good margin after the discount and a supplier who can deliver in time.
- Sell what you have: products with long lead times or low margins. Promote them, but set a limit, and switch them off when they run out.
- Leave out of the sale: anything that loses money at the discount or that you cannot restock.
Tips
- Count your stock before you order. Your store's stock number and the shelf often disagree.
- Set low stock alerts in your store so you know before a product sells out.
- Plan what customers see if a product does sell out: hide it, or show a back-in-stock signup.
- Check packaging and shipping supplies too. Boxes and mailers run out as well.
- After the sale, compare your forecast with actual sales and note the real uplift for next year.