Inventory glossary
What is Intermittent demand?
Intermittent demand is a sales pattern where a product sells in occasional, irregular bursts with many periods of zero sales in between, rather than a steady stream of orders.
Intermittent demand matters because it breaks forecasting models built for steady sellers. A store owner who treats a lumpy SKU like a regular one will either overstock after a single busy week or run out right after a quiet stretch ends and demand returns.
Spotting intermittent demand early lets you set reorder points and safety stock based on the real pattern, not a smoothed-out average that never actually happens week to week. It also helps you decide which slow, irregular SKUs are worth keeping on the shelf at all.
Example
A candle shop sells a limited-edition scent: 4 units in week 1, 0 units in weeks 2 through 5, 3 units in week 6, then 0 again for three more weeks. Over 9 weeks that is 7 units sold, averaging under 1 unit per week, but all the sales happened in two short bursts. A standard weekly average forecast would miss both the slow stretches and the bursts.
Common mistakes
- Using a simple average of all periods, which hides the gaps and overestimates typical demand.
- Setting a reorder point as if demand is steady, causing stock to sit unsold for months.
- Panicking and reordering right after a sales burst, before confirming it is a pattern and not a one-off.
Intermittent demand and SteadyShelf
SteadyShelf's forecasting looks at each SKU's actual sales pattern, so a slow, lumpy seller does not get treated the same as a steady one when it suggests reorder timing and quantities.
SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.
Related terms
Lumpy demand · Demand variability · Safety stock · Slow-moving inventory · Long tail SKUs
FAQ
How do I know if a product has intermittent demand instead of just being slow-moving?
Yes, if sales are sporadic but not zero most of the time, like a backup phone case model selling twice a month, it is intermittent. If it sells only during one holiday and nothing else all year, it is more seasonal.
Why does a normal forecasting formula not work well for intermittent demand?
A simple average works for steady sellers. For intermittent demand it overstates typical weeks and understates the long gaps, so you either hold too much stock or run out between orders. Methods built for sparse data give better order timing.
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