Demand forecasting
Intermittent Demand
By the Supply Chain Manager team · Updated October 16, 2026
Intermittent demand is sales that come in occasional bursts, with many periods of zero demand in between, common for spare parts and specialist items.
Standard methods forecast intermittent items poorly: an average spreads demand thinly over periods when nothing sells, then falls short when an order arrives. Specialized methods such as Croston's method forecast the size of orders and the gap between them separately.
Lumpy demand is intermittent demand where order sizes also vary a lot. It is the hardest pattern to forecast and often better handled with a stocking policy than a precise forecast.
Intermittent demand example
Illustrative numbers: a pump seal sold 0, 0, 12, 0, 0, 0, 10, 0 units over eight weeks. Its average is 2.75 a week, but no week actually sold 2.75; real demand arrives about every three to four weeks, in batches of 10 to 12.
Why intermittent demand matters for distributors
Distributors of industrial, electrical and maintenance supplies often have many intermittent SKUs. Handling them with the wrong method creates both stockouts and dead stock.
Common intermittent demand mistakes
- Judging intermittent forecasts with MAPE, which breaks on zero-demand periods.
- Holding stock to the average instead of to the typical order size.
Intermittent demand in Supply Chain Manager
Supply Chain Manager tests Croston's method and its SBA variant on SKUs whose history shows intermittent demand.
Open the live demoExamples on this page use made-up round numbers to show the calculation. They are not benchmarks or results from real businesses.