Both safety stock formulas, a service level dropdown, and the reorder point. Change any input and the results update. Everything runs in your browser and nothing is saved.
Pull these from sales history and supplier records. Daily units and days.
130units
Z (1.645) × σ demand × √ lead time
If lead time is stable, the statistical figure is your buffer. If deliveries swing, use the combined figure, and notice how much of it comes from the supplier rather than from demand.
It plans for the busiest day and the slowest delivery landing together. That almost never happens, which is why it usually runs several times higher than the statistical answer.
The σ in the formula is really the standard deviation of your forecast misses. Cut the misses by 40% and the buffer at the same service level drops by 40%. Read the full walkthrough.
=NORM.S.INV(0.95)*STDEV.S(B2:B366)*SQRT(10) gives the statistical buffer for a 95% service level, a demand range in B2:B366, and a 10-day lead time.
Pecan builds the demand forecast that shrinks the σ. See it on your SKUs.
