Perpetual vs Periodic Inventory: Differences

By mise · Updated September 29, 2026

Quick answer: a perpetual system updates stock with every purchase and sale; a periodic system only knows stock when you count, and COGS is beginning inventory + purchases − ending inventory. Most small businesses run periodic with regular counts, or a light perpetual system.

The difference is not only accounting: with perpetual you know what you have without walking to the stockroom; with periodic you find shrink at the end.

	Perpetual	Periodic
Updates	Every transaction	At each count
Stock known	Any time	After counting
COGS	Per sale	Beginning + purchases − ending
Shrink	Visible as it happens	Found later

mise combines both: every delivery and adjustment is recorded, and physical counts confirm the numbers.

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Keep reading Restaurant COGS: how to calculate cost of goods sold Beginning and ending inventory: formulas and examples Cycle Counting: How to Do Inventory Cycle Counts Inventory Valuation Methods: FIFO, Average, Specific All guides

Frequently asked questions

Does perpetual inventory remove the need to count?

No: physical counts still verify the records.

Which is better for a restaurant?

Periodic with weekly counts works well; perpetual needs recipe-level sales data.

How is COGS calculated under periodic?

Beginning inventory + purchases − ending inventory.

How much does mise cost?

A 7-day free trial, then US$33 a month per location (£26 in the UK).