How do you calculate economic batch size?

Take the square root of (2 x annual demand x setup cost) divided by the annual holding cost per unit. With 24,000 units, a $320 setup, and $1.80 holding cost, that is sqrt((2 x 24,000 x 320) / 1.80) = about 2,921 units.

What is the difference between EOQ and economic batch size?

They share the same square-root formula, but EOQ is an order quantity for purchased goods (ordering cost) while EBS is a production run quantity (setup/changeover cost). EBS variants can also subtract a production-rate term when items are made and consumed simultaneously.

How many runs per year does this batch size give?

Divide annual demand by the batch size. For 24,000 units at a 2,921-unit batch, you get about 8.2 production runs per year, or roughly one run every 30 days.

What is days of supply for this batch?

Divide the batch by daily demand. At 96 units/day and a 2,921-unit batch, each run covers about 30 days of supply before you need to run the part again.

Should I always run the exact economic batch size?

No. Round to a sensible multiple of your pallet, tote, or tooling cavity count, and check it against shelf life and storage. The cost curve is flat near the optimum, so a batch within 15-20% of EBS costs almost the same.

How does reducing setup cost change the batch?

Lower setup cost shrinks the optimal batch, because cheaper changeovers let you run smaller, more often. Halving the $320 setup drops the batch to about 2,066 units, which is the whole point of SMED and quick-changeover work.

Planning calculator

Batch Size Calculator

Economic Batch Size (EBS) is the production run quantity that minimizes the combined cost of machine setups and inventory carrying. Planners and production schedulers use it to decide how many parts to make per run instead of guessing round numbers like 1,000 or 5,000. Run too small and you bleed money on frequent changeovers; run too big and you tie up cash and floor space in stock that sits for weeks. EBS is the lean answer to 'how big should this batch be?' and it directly drives setup labor, WIP, and inventory turns.

What this calculator does

Estimate an economic batch size using setup cost, holding cost, and demand.
Use when balancing changeover cost against inventory cost.
It computes the run quantity that minimizes total setup-plus-holding cost, then translates that into runs per year and days of supply.

Formula used

Economic batch size = √((2 × annual demand × setup cost) ÷ holding cost)
Runs per year = annual demand ÷ batch size
Days of supply = batch size ÷ daily demand

Inputs explained

Annual demand: undefined
Setup cost per run: undefined
Annual holding cost per unit: undefined
Working days per year: undefined

How to use the result

Use it when scheduling repetitive parts on shared equipment where each run requires a meaningful changeover and finished stock incurs a carrying cost.
The classic EBS formula assumes steady demand and constant costs; lumpy demand, shelf-life limits, or shared-tooling constraints can make the math-optimal batch impractical.

Current U.S. benchmarks

U.S. manufacturing runs at 75.6% of capacity (Federal Reserve, May 2026). New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate economic batch size? Take the square root of (2 x annual demand x setup cost) divided by the annual holding cost per unit. With 24,000 units, a $320 setup, and $1.80 holding cost, that is sqrt((2 x 24,000 x 320) / 1.80) = about 2,921 units.
What is the difference between EOQ and economic batch size? They share the same square-root formula, but EOQ is an order quantity for purchased goods (ordering cost) while EBS is a production run quantity (setup/changeover cost). EBS variants can also subtract a production-rate term when items are made and consumed simultaneously.
How many runs per year does this batch size give? Divide annual demand by the batch size. For 24,000 units at a 2,921-unit batch, you get about 8.2 production runs per year, or roughly one run every 30 days.
What is days of supply for this batch? Divide the batch by daily demand. At 96 units/day and a 2,921-unit batch, each run covers about 30 days of supply before you need to run the part again.
Should I always run the exact economic batch size? No. Round to a sensible multiple of your pallet, tote, or tooling cavity count, and check it against shelf life and storage. The cost curve is flat near the optimum, so a batch within 15-20% of EBS costs almost the same.

Last reviewed 2026-05-12.