Takt and staffing, from your own numbers
The calculator
Type in one shift: its length, its breaks and planned stops, the units it has to make, and the seconds of work each station does on one unit. The page works out the takt time, how far each station sits from it, and the fewest people each station needs to keep the beat.
Every figure comes with the sum that produced it, so you can check it against your own floor. Nothing you type leaves this page; there is nothing to send and nothing is kept.
Work it out
One shift, worked through
42.0 s takt — one unit every 42.0 seconds, 85.7 an hour
- Working time. 8 h 00 min is 480 min; less 45 min of breaks and 15 min of planned stops leaves 420 min, which is 25,200 s.
- Takt. 25,200 s ÷ 600 units = 42.0 s per unit.
- Pick. 38.0 s of work against a 42.0 s takt is 4.0 s under it, so one person keeps the beat with a load of 90%.
- Check. 22.0 s of work against a 42.0 s takt is 20.0 s under it, so one person keeps the beat with a load of 52%.
- Pack. 51.0 s of work against a 42.0 s takt is 9.0 s over it: 51.0 ÷ 42.0 = 1.21, rounded up to 2 people. With 2, each unit takes 25.5 s of the beat, a load of 61%.
- Label and despatch. 14.0 s of work against a 42.0 s takt is 28.0 s under it, so one person keeps the beat with a load of 33%.
- All stations. 125.0 s of work per unit ÷ 42.0 s = 2.98, so no layout can make this demand with fewer than 3 people. Station by station, as typed, it needs 5.
- The slowest step. As laid out, Pick sets the pace at 38.0 s per unit, so the shift can make 663 units.
The words
What the words mean here
- Takt time
- The working time in a shift divided by the units wanted in it. It is the beat the whole flow has to keep, set by demand rather than by how fast anyone works.
- Seconds of work
- The time one person needs to do a station's work on one unit, from picking it up to passing it on. If the station involves walking, the walk is part of its seconds.
- Gap
- Takt minus a station's seconds of work. A positive gap is time the station waits each beat; a negative one is time it falls behind, every unit.
- People at a station
- The seconds of work divided by the takt, rounded up, because a fraction of a person cannot stand at a station. Our convention: always round up, never down.
- Load
- How much of each beat the people at a station are busy: seconds of work divided by people times takt.
- Fewest people overall
- All the seconds of work added up and divided by the takt, rounded up. It is the floor no rebalancing can go under; the gap between it and the station-by-station count is what rebalancing works on.
What it misses
What the arithmetic cannot see
These sums treat every unit as the same. Real floors vary: a heavy order, a missing label, a new starter on their second day. Time a run of units on the floor, use a typical figure here, and look at the spread separately — a station whose times swing widely needs more room than its average suggests.
Changeovers, absence, equipment stops and the queue a slow step builds are not in these numbers either. They are exactly what a walk and a baseline are for, and why we take times on the floor rather than from a spreadsheet of standards.