Perpetual vs Periodic Inventory Systems: Key Differences, Pros & Cons
Perpetual inventory tracks every item in real time; periodic inventory counts stock only at set intervals—monthly, quarterly, or annually.
Store owners eyeing the same shelves often think both systems “count stuff,” so they pick whichever sounds cheaper. In reality, one keeps you updated like a live news ticker, while the other delivers a snapshot like a yearbook photo.
Key Differences
Perpetual: constant updates via barcode/RFID, higher tech cost, immediate COGS. Periodic: bulk counts, lower tech spend, delayed COGS, potential shrinkage surprises.
Which One Should You Choose?
High-volume or e-commerce? Go perpetual for real-time accuracy. Small gift shop with steady turnover? Periodic saves cash and time until growth demands tighter control.
Can you switch from periodic to perpetual later?
Yes—most POS systems allow migration, but expect a one-time full count and staff training.
Is perpetual always more expensive?
Upfront, yes, yet lower stockouts and theft can offset costs within a year.