Replenishment Quantity Calculator

Work out replenishment quantity instantly with clear inputs, formula shown and shareable results.

About Replenishment Quantity Calculator

Replenishment quantity is the target stock less what is on hand and already on order, rounded up to whole cases. The rounding overage matters for slow-moving lines, where a single case can represent several months of cover.

Formulas

Net requirement

Net requirement = Target stock - On hand - On order

Order quantity

Order = ceiling(Net requirement / Case size) x Case size

Worked example

With the default values below, Replenishment Quantity Calculator returns Order quantity of 312. Change any input above and every figure here is recalculated in your browser.

Inputs used

Target stock level: 600
Current stock on hand: 180
Units already on order: 120
Case or pack size: 24

Results

Order quantity: 312
Cases to order: 13
Net requirement before rounding: 300
Extra units from case rounding: 12

Step by step

1Values used
2Net requirement
3Order quantity
4Order quantity= 312
5Cases to order= 13
6Net requirement before rounding= 300
7Extra units from case rounding= 12

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why round up rather than down?

Because rounding down creates a shortfall against the target and risks a stockout before the next replenishment cycle.

What if the case size is too large for the line?

Negotiate a smaller pack, or accept a longer review cycle. Ordering full cases of a very slow line is a common cause of excess stock.