# EPEI (Every Product Every Interval)

**URL:** https://kaizumi.com/dictionary/epei

**Description:** EPEI measures how frequently a process can produce every product in its mix, indicating production flexibility and responsiveness.

**Category:** lean-tools

**Tags:** flow, metrics, advanced

## Definition

EPEI (Every Product Every Interval) measures how often a process can produce its complete product mix. If a line can produce every SKU once per week, EPEI is one week. If it can produce every SKU every day, EPEI is one day. Shorter EPEI means greater flexibility and responsiveness—customers wait less, finished goods inventory is lower, and demand changes are absorbed faster. EPEI is primarily determined by changeover time and frequency; reducing changeover time through SMED enables more frequent changeovers and shorter EPEI.

## Examples

### Manufacturing

> A packaging line runs 20 SKUs. With 2-hour changeovers, they batch large quantities and achieve EPEI of two weeks—each SKU runs once per two weeks. After SMED reduced changeover to 15 minutes, they run smaller batches more frequently, achieving EPEI of one day. Finished goods inventory dropped 80%.

### Healthcare

> A hospital kitchen serves 30 different meals. Originally, each meal was prepared weekly in large batches (EPEI = 1 week), requiring freezing. Process improvements reduced setup time between meals, enabling daily preparation of all options (EPEI = 1 day), eliminating freezing and improving quality.

### Administrative

> A print shop produces 50 standard products. Long press setups meant each product ran monthly (EPEI = 1 month), requiring large print runs. Digital press technology with instant changeover enabled EPEI of 1 day, dramatically reducing inventory and enabling faster customer response.

## Key Points

- EPEI = total changeover time / available changeover time per interval
- Shorter EPEI means lower inventory and faster response
- SMED (changeover reduction) is the primary lever for improving EPEI
- Not all products need the same frequency—A items may run daily while C items run weekly

## Common Misconceptions

**EPEI must be the same for all products.** High-volume A items may need daily or more frequent production while low-volume C items may only need weekly or monthly runs. EPEI targets should align with demand patterns and customer expectations.

**Short EPEI always justifies the investment.** Changeover reduction has costs. If customers are satisfied with current lead times and inventory costs are manageable, extremely short EPEI may not provide sufficient return.

## Try It

Calculate your own EPEI right here. Enter available minutes per day and each part's cycle time, demand, and setup time to find how often you can cycle through every part. (Also available as a [standalone tool](/tools/epei).)

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## See Also

- [Heijunka](/dictionary/heijunka) - Leveling production
- [SMED](/dictionary/smed) - Single Minute Exchange of Die

Source: https://kaizumi.com/dictionary/epei
Licence: free to quote and cite with attribution to Kaizumi.