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Just In Time Batch Size Calculator

Work out just in time batch size instantly with clear inputs, formula shown and shareable results.

About Just In Time Batch Size Calculator

Just-in-time batching uses the economic production quantity, the EOQ variant that accounts for goods being consumed while they are still being made. The (1 - d/p) factor shrinks peak inventory, and lower changeover cost is what allows genuinely small batches.

Formulas

Economic production quantity

EPQ = sqrt(2 D S / (H x (1 - d/p)))

Peak inventory

Peak = EPQ x (1 - d/p)

Worked example

With the default values below, Just In Time Batch Size Calculator returns Economic batch (production) quantity of 5,409. Change any input above and every figure here is recalculated in your browser.

Inputs used

Annual demand (units)
96,000
Setup or changeover cost per batch
320
Annual holding cost per unit
4.5
Annual production capacity (units)
180,000

Results

Economic batch (production) quantity
5,409
Batches per year
17.7
Peak inventory
2,524
Annual setup + holding cost
$11,358.87

Step by step

  1. 1Values used
  2. 2Economic production quantity
  3. 3Peak inventory
  4. 4Economic batch (production) quantity= 5,409
  5. 5Batches per year= 17.7
  6. 6Peak inventory= 2,524
  7. 7Annual setup + holding cost= 11,358.87

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 or tax into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

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

Frequently Asked Questions

How do I make batches smaller?

Attack setup cost. Halving changeover time reduces the economic batch by about 29%, which is the whole logic behind SMED and quick-change tooling.

What if production rate is below demand?

Then the line cannot keep up and the formula collapses to plain EOQ; capacity, not batching, is the constraint.

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