Batch Size Calculator
Enter the yearly demand, the cost of setting up each batch, the cost of holding one unit for a year and, if you make the item, the daily production rate. The calculator gives the batch size with the lowest total cost.
- Economic batch quantity
- EOQ for orders
- Batches a year
Holding cost includes storage, insurance, spoilage and the cost of money tied up, often 15% to 30% of the unit's value a year. Enter 0 production rate for bought-in items.
Big batches save setup costs but tie up money in stock. The best batch size balances the two. The economic order quantity, √(2 × demand × setup cost ÷ holding cost), puts setup and holding costs exactly level. With 10,000 units a year, 200 per setup and 2 a unit to hold, it is 1,414 units.
Batch size chart
Setup 200, holding 2 a unit a year. Search for a demand.
| Yearly demand | Batch size | Batches a year |
|---|---|---|
| 1000 | 447 | 2.2 |
| 2500 | 707 | 3.5 |
| 5000 | 1000 | 5 |
| 10000 | 1414 | 7.1 |
| 20000 | 2000 | 10 |
| 50000 | 3162 | 15.8 |
| 100000 | 4472 | 22.4 |
Bought-in items, no production rate.
Demand and batch size
Setup 200, holding 2. Slide the yearly demand.
The sawtooth is stock over the year: it jumps up with each batch and falls as it is used.
How to work out batch size
Balance the costs. Step through it.
Demand
A year.
If you make the item, stock builds up more slowly while you use some, so the best batch is a little larger.
EOQ, EPQ or just-in-time
Approaches. Compare them.
Bought-in orders.
Made in-house.
Tiny batches.
Cutting setup time is the most powerful way to make smaller batches pay.
Before using it
Batch checks. Tick each item.
Tick each item as you go.
Round the batch to fit pallets, containers or machine runs. The total cost curve is flat, so a small change costs very little.
What you get
Batch planning. Each tile explains one result.
Units.
A year.
Days between.
Units.
Setup plus holding.
Halving setup cost cuts the best batch size by about 30%.
Frequently Asked Questions
No question matches that search.
What is the economic batch quantity?
The batch size that gives the lowest total of setup and holding costs.
What is the EOQ formula?
EOQ = √(2 × yearly demand × order cost ÷ holding cost per unit a year).
What is holding cost?
The cost of keeping one unit in stock for a year, including storage and money tied up.
What is the difference between EOQ and EPQ?
EPQ allows for stock being used while a batch is still being made, so batches are a little larger.
Why are setup and holding costs equal at the best batch size?
That is where the total cost curve is at its lowest.
How do I make smaller batches pay?
Reduce setup time and cost. Smaller setups mean smaller best batches.
Does the formula work for changing demand?
It assumes steady demand. Recalculate as demand changes.
The batch that costs least
Balance setup and holding costs to find the best batch size, then round it to something practical. Recheck it whenever demand or costs change.
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