Days of Inventory Cover Calculator
Calculate how many days your current stock will last at average demand. Enter available stock and average daily demand to get days of cover.
Days of inventory cover estimates how long your current stock will last at the average usage rate. It is a fast health check for each item and for total inventory.
How it works
Divide available stock by average daily demand. Keep both in the same unit, whether units, cases, or value.
The formula
Days of cover = available stock / average daily demand. For a value basis over a year, weeks of cover = stock value / annual usage x 52.
Worked example
With 600 units on hand and average demand of 100 units/day, days of cover = 600 / 100 = 6 days.
Frequently asked questions
What is the difference from inventory turnover?
Days of cover is forward-looking from current stock and expected demand; turnover is a backward-looking ratio over a completed period.
Does it account for demand spikes?
No. It uses average demand, so pair it with safety stock and a reorder point for variable items.
Can I use it on value instead of units?
Yes, as long as stock and demand are both expressed in the same unit or currency basis.