How do you calculate starved and blocked time?

Divide the starved minutes and the blocked minutes by the observed minutes. 22 starved and 14 blocked minutes in a 450-minute shift are 4.9% and 3.1%, 8% in all, 3 points over a 5% limit, and 360 units at 600 an hour if the station is the constraint, the Starved/Blocked Time calculator's own example.

What is the difference between starved and blocked?

A starved station is ready but has nothing to work on, because the station before it has not delivered. A blocked station has finished but cannot pass the work on, because the station or buffer after it is full.

How does starved and blocked time point to the constraint?

Stations before the constraint fill up and block; stations after it run dry and starve. The station between a run of blocked stations and a run of starved ones is the constraint, the leak test in the example.

Why does only the constraint's lost time cost output?

The constraint sets how many units the line makes. A minute lost there is a minute of output lost for the whole line; a minute lost at a faster station is made up while it waits for the constraint anyway.

Does it count breakdowns?

No. Breakdowns, changeovers and quality stops at the station are its own losses, not flow losses. Record them in a downtime tracker; this workbook is about waiting caused by the line.

Does the workbook use macros?

No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test observations and shows Self-check: PASS.

Production and Throughput

Starved and Blocked Time Tracker Excel Template

Starved and blocked share = (starved + blocked minutes) ÷ observed minutes. Log every station's shift on an assembly or packaging line and see where work waits, which stations exceed your flow loss limit, the pattern that points to the constraint, and the output its lost minutes cost the line.

Free, and a plain .xlsx with no macros to enable. A CSV with live formulas and a printed how-to guide come with it.

Overview

This starved and blocked time tracker is a working Excel workbook for industrial and manufacturing engineers, line supervisors and continuous improvement teams. Each station has a row each shift with the minutes it was observed, the minutes it stood ready with nothing to work on (starved) and the minutes it stood finished with nowhere to pass the work (blocked); each station's running rate comes from Setup, where you also set the flow loss limit and name the constraint. The workbook gives each observation's starved, blocked and total share, the margin to the limit, the minutes lost and the units they would cost if that station were the constraint, then totals every station over the log. It ships with five shifts on a fictional seven-station engine assembly line, so every tile and chart is filled in when you open it.

In the example the three stations before the leak test are blocked 7 to 10% of the time and the three after it are starved 8 to 9%: the classic pattern around a constraint. The leak test itself loses only 3.6% of its time, within the 5% limit, yet those 80 minutes over five shifts are 73 engines the line never builds, because it sets the pace. The other stations' larger losses cost nothing until the leak test is faster than they are.

Breakdowns, changeovers and quality stops at a station are not starved or blocked time and are not counted. The download is a plain .xlsx with no macros. A CSV with live formulas is also included for other tools; the dashboard, charts, dropdowns and self-check are in the .xlsx.

What this template includes

Setup sheet with your line, the flow loss limit and the constraint station, and the stations with their name and running rate
Observations table, one row per station per shift: date, observed, starved and blocked minutes, with a Check column
Per observation: starved, blocked and total share, margin to the limit in points, minutes lost, output lost if the station is the constraint, and a status in words
Dashboard with four tiles (hours observed, starved and blocked share against the limit, stations over the limit, output lost at the constraint), starved and blocked share by station in line order, output lost if each station were the constraint, and the station table
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference and the Starved/Blocked Time calculator (Self-check: PASS)
CSV with live formulas for the Observations table; the dashboard, charts, dropdowns and self-check are in the .xlsx

Suggested use case

Use it to find a line's constraint from where work waits, to measure what its lost minutes cost, or to check whether a rebalance or buffer change reduced starving and blocking.

How to use it

On Setup, type your line, the flow loss limit and the constraint station, and list your stations with their name and running rate.
On Observations, give each station a row each shift: date, observed minutes, starved minutes and blocked minutes.
Fix anything the Check column names.
Open the Dashboard: starved and blocked share by station, and the output lost at the constraint.

Frequently Asked Questions

How do you calculate starved and blocked time?: Divide the starved minutes and the blocked minutes by the observed minutes. 22 starved and 14 blocked minutes in a 450-minute shift are 4.9% and 3.1%, 8% in all, 3 points over a 5% limit, and 360 units at 600 an hour if the station is the constraint, the Starved/Blocked Time calculator's own example.
What is the difference between starved and blocked?: A starved station is ready but has nothing to work on, because the station before it has not delivered. A blocked station has finished but cannot pass the work on, because the station or buffer after it is full.
How does starved and blocked time point to the constraint?: Stations before the constraint fill up and block; stations after it run dry and starve. The station between a run of blocked stations and a run of starved ones is the constraint, the leak test in the example.
Why does only the constraint's lost time cost output?: The constraint sets how many units the line makes. A minute lost there is a minute of output lost for the whole line; a minute lost at a faster station is made up while it waits for the constraint anyway.
Does it count breakdowns?: No. Breakdowns, changeovers and quality stops at the station are its own losses, not flow losses. Record them in a downtime tracker; this workbook is about waiting caused by the line.
Does the workbook use macros?: No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test observations and shows Self-check: PASS.