Just-in-Time Inventory Calculator
What JIT saves, and what it risks.
Net annual benefit of JIT
$950
the savings outweigh the risk
The savings are steady and the failures are concentrated — make sure supply reliability actually supports the assumed stockout rate.
How the Just-in-Time Inventory Calculator works
Just-in-time minimises stock by taking delivery as close as possible to the point of need. It frees a great deal of cash and removes almost all margin for error — the savings are certain, the risk is occasional and large, and the comparison is worth doing explicitly.
Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price — check the platform's current fee schedule before you price a product against it. This is not tax or business advice.
Frequently asked questions
What does JIT actually save?
Carrying cost on the inventory no longer held, typically 20-30% of that value annually, plus the capital freed for other uses. On £100,000 of stock removed, that is £20,000-30,000 a year plus whatever the cash earns elsewhere.
What does JIT risk?
Everything depends on supply reliability. One late shipment, one port delay, one supplier problem becomes an immediate stockout because there is no buffer. The savings are steady; the failures are concentrated and expensive.
Is JIT suitable for a small ecommerce business?
Rarely in full. It needs highly reliable short-lead-time suppliers, which small buyers seldom command. A partial approach — lean on predictable fast movers, buffered on volatile or long-lead items — captures much of the benefit with far less exposure.
How do I decide?
Compare annual carrying cost saved against expected annual stockout cost at the leaner level. If supply is reliable and stockout cost is modest, JIT wins. If either fails, the buffer is cheap insurance.