My sales double in Ramadan and my supplier slows down before Eid: how do I choose safety stock for that season?
Calculate the season separately from the rest of the year. Enter last Ramadan's average daily sales and its usual lead time, then switch safety stock to derive from maximums and enter the busiest day and the longest delay you saw that season. The result is a cautious figure that can be large, so weigh it against cash and space before relying on it, and go back to your normal numbers after Eid.
Why the yearly figure fails in season
The calculator assumes steady daily sales and a fixed lead time, and knows nothing about Ramadan or Eid. Enter the whole year's average and the few weeks when sales double get lost among quiet months, so the reorder point comes out far lower than the season needs. The simple fix: treat the season as if it were a different product, with its own numbers.
Example: the season against normal months
In normal months you sell 10 units a day, the supplier delivers in 8 days, and you keep 40 units of safety stock. Last Ramadan, average sales were 20 a day and the usual lead time 10 days, but the busiest day hit 45 units and the supplier's longest delay before Eid was 14 days.
Normal months: 10 × 8 = 80, reorder point 80 + 40 = 120 units.
The season, safety stock from maximums: highest usage 45 × 14 = 630, usual usage 20 × 10 = 200, safety stock 630 − 200 = 430 units.
Seasonal reorder point: 200 + 430 = 630 units.
Notice that the seasonal reorder point came out exactly equal to the highest usage, 630. That is no coincidence: with safety stock derived this way, the whole reorder point covers your busiest day repeated across your longest delay. You are preparing for a season in which peak sales and the worst delay coincide for the entire wait. That is rare, which is why the figure is cautious.
How to tell whether the figure is too big
- Was the busiest day a one-off, such as a special offer night, or did it recur through the season? If it was an exception, use a figure closer to your usual busy days.
- Can you pay for 630 units before the season without squeezing your other commitments?
- Do you have room to store them, and what happens to what is left after Eid? A seasonal product may not sell as fast afterwards.
- If the answer is no, enter a smaller safety stock yourself and accept a slightly higher risk of running out. The calculator works with what you enter; the decision is yours.
The steps
- In the Inventory reorder-point calculator, enter the season's average daily sales and its usual lead time.
- Choose 'Derive from maximums' and enter last season's highest daily sales and longest lead time.
- Read the highest usage, the derived safety stock and the reorder point, and press 'Copy result' to keep them.
- After Eid, switch back to entering safety stock yourself with your normal figures, so you are not holding seasonal stock through quiet months.
Send the seasonal order early with a clear purchase order from the Purchase-order generator. If you are buying a large quantity for one season, check with the Break-even calculator how many units you need to sell to cover the season's fixed costs.
Common questions
Should I use last season's figures as they are?
They are the best starting point, but adjust them if something clearly changed, such as a new sales channel or a substitute product. The calculator does not forecast growth; it works only with what you enter.
When do I start using the seasonal figures?
At least one lead time before the season, because an order that lands after the rush has started is no help. Switch to the seasonal point as soon as your next order could be affected by the season.