A blanket purchase order commits to a supplier, agreed prices and a total value over a period, with deliveries drawn against it. For repeat buying it removes a great deal of administration and concentrates the approval at the only point where it means anything, which is the total. It also introduces one risk that ordinary orders do not carry.
What it is good for
The same items from the same supplier repeatedly: consumables, materials, recurring services. Rather than an order per delivery, one order fixes the terms and each delivery draws against it. Approval happens once, at the blanket value, which is both the efficiency and the reason that value deserves proper thought.
The risk: silent drawdown
Cumulative deliveries can pass the approved total one at a time with nobody noticing, because no individual delivery looks significant. A visible remaining balance and an alert as it nears the limit turn that from a discovery into a decision. Without them a blanket order is an unmonitored spending permission.
Expiry and price review
Blanket orders should end on a date, and the price agreement behind them should be revisited at the same time. Open-ended blankets outlive their agreements and deliveries get drawn at prices nobody has checked in two years. An expiry forces that conversation on schedule rather than leaving it to somebody noticing.
Questions people ask about blanket purchase order
How does matching work against a blanket?
Against the agreed prices and the receipts for each delivery, with the drawdown tracked. Line-level receipting matters even more than usual.
How long should one run?
Usually a quarter or a year, aligned with how often you would want to revisit prices with that supplier.
Do blanket orders weaken control?
Only without drawdown tracking. With a visible balance and an expiry they concentrate the control where it is most useful.