Home / Flow & productivity

SMED and EPEI calculator

Enter the current changeover, how much can become external and how much internal work can shrink to see the new changeover time, hours freed per year, the mix EPEI and the value of the gain.

Pre-sizing and estimating tool: results do not replace design, calculations or reports signed by a licensed professional, nor verification against the applicable codes and standards.

Preliminary estimate
Changeover

Examples: preparing tools and materials before stopping (becomes external); quick clamps, standardized heights and parallel work (reduce internal time).

Product mix (EPEI)
Value of the gain
Economic analysis
—New changeover time
—

Changeover before and after SMED

Internal time (machine stopped) and external time (machine running) at each stage of the method.

Tap the chart to see the values.

EPEI versus changeover time

Days to run the whole mix with the day’s free time. Points mark the current and proposed situations.

Tap the chart to see the values.

Project payback

Cash flow of the improvement: investment in year 0 and annual savings escalated at the rate entered, discounted at the MARR.

Tap the chart to see the values.

The report gathers this page's inputs, results, equations, assumptions and references, with fields for project, engineer and revision. In the print dialog, choose Save as PDF.

Method, assumptions and references

Equations used

New changeover = current × (1 − external share) × (1 − internal reduction)
Hours freed per year = (current − new) ÷ 60 × changeovers per week × weeks
EPEI (days) = items × changeover time ÷ (available time per day − run time per day)
Smaller lots: cycle stock ∝ lot size ∝ changeover time (same total changeover time)

Assumptions and limits

  • Conversion and reduction percentages estimated by the team from filming and analyzing the changeover; typical results range from 50% to 90% reduction.
  • The margin-based hourly value only applies to a bottleneck with demand; otherwise use avoided hourly cost or inventory reduction.
  • EPEI assumes one changeover per item in each mix cycle and constant run time.

Standards and technical documents

  • Shingo, S. A Revolution in Manufacturing: The SMED System. Productivity Press, 1985
  • Smalley, A. Creating Level Pull. Lean Enterprise Institute, 2004 (EPEI)
  • Rother, M.; Shook, J. Learning to See. Lean Enterprise Institute, 1999

U.S. regulations

  • OSHA 29 CFR 1910.147: lockout/tagout applies to setups and changeovers; the minor servicing exception requires alternative effective protection
  • OSHA General Duty Clause: ergonomic risks of manual tool handling

Frequently asked questions

How do you apply SMED?

Film the changeover, list the activities, separate those that need the machine stopped (internal) from those that can be done before or after (external), convert as many internal tasks as possible and streamline the rest with quick clamps, standardization and parallel work.

What is EPEI?

It is the interval in which every item in the mix can be run at least once. With 12 items, 180-minute changeovers and 2.5 free hours per day, EPEI is 14 days; at 70 minutes per changeover it drops below 6.

Should SMED gains be used for more output or smaller lots?

If the equipment is a bottleneck with demand, use the time to make more. If not, run smaller lots: inventory and lead time fall and the plant responds faster.