You have to run the line 24/7, or your shift is already racking up overtime. The schedules that are circulating outline a rotation without specifying who is assigned to each shift. But at night, if the only trained person is absent, the line stops, or a coworker has to come in from their time off.
The scheduling of a factory's rotating shifts is a three-step process: the pace, the roster, and then the skills of each team. It's the third one who decides whether the line runs at night.
Which rhythm should I choose: 2×8, 3×8, 4×8, 5×8, or 2×12?
Each line operates on a schedule that covers its hours, so 2×8 or 3×8 if she takes the weekend off, and 5×8 otherwise. A workshop that operates only during the day is a staff scheduling classic.
If your production line runs 24 hours a day but stops on weekends, you are operating on a semi-continuous schedule. If it never stops, you are operating on a continuous operation, which is governed by a separate law.
| Rhythm | Teams | Cover | Typical Cycle | Average hours per week |
|---|---|---|---|---|
| 2×8 | 2 | 16 hours a day, Monday through Friday | Alternating between mornings and afternoons | 40 hours |
| 3×8 | 3 | 24 hours a day, Monday through Friday | One week of morning shifts, one week of afternoon shifts, and one week of night shifts | 40 hours |
| 4×8 | 4 | 24 hours a day, 7 days a week | 2 mornings, 2 afternoons, 2 nights, 2 days off | 42 hours |
| 5×8 | 5 | 24 hours a day, 7 days a week | 2 mornings, 2 afternoons, 2 nights, 4 days off | 33.6 hours |
| 2×12 | 4 | 24 hours a day, 7 days a week, 12-hour shifts | 2 days, 2 nights, 4 rest days | 42 hours |
When your employees work continuously in successive shifts as part of a continuous cycle, the Labor Code caps their weekly hours at an average of 35 hours per year (Article L3132-15). This cap determines the number of shifts.
For continuous operation, we recommend the 5×8 schedule. The 4×8 schedule requires each employee to work 42 hours per week, and hours worked beyond 35 are converted into days off, during which the operator must be replaced.
Figure 1. Average hours per week, depending on the schedule
Continuous work schedules exceeding 35 hours (in red) result in a gap in rest days; the 5×8 schedule (in purple) remains below that threshold. Shown in gray are Monday-through-Friday schedules, which are not subject to this limit.
2×8, Monday through Friday
3×8, Monday through Friday
4×8, continuous
5×8, continuous
2×12 with 4 teams, continuous play
Calculation: 168 hours per week divided by the number of shifts (8-hour shifts, 12-hour shifts for the 2×12 schedule). Limit: Labor Code, Art. L3132-15. Updated: October 2026.
In terms of health, the 4×8 and 5×8 shifts are comparable, with two consecutive nights each. The 5×8 shift has the edge in terms of staffing levels and its four days of rest after the nights, compared to two.
Is it possible to keep teams on fixed schedules?
Yes. To operate 24 hours a day without a night shift, the INRS proposes a 2×8 schedule combined with a permanent night shift, made up primarily of volunteers.
No one changes their pace, but this team stands apart. Give them their own starters at every key position, since no substitutes are coming in to reinforce them.
12-hour shifts require an agreement
A 12-hour shift is legal only if a company-wide or industry-wide agreement. Unless otherwise agreed, a shift ends at 10 a.m. during the day and at 8 p.m. at night.
However, the 12-hour shift does not reduce the workforce, since the position remains open for the same number of hours throughout the year. A 12-hour shift schedule cannot, therefore, be implemented as is.
How many teams are needed for a 3×8 schedule, 7 days a week?
A 3×8 shift on a 7/7 schedule requires five teams to stay under 35 hours of continuous work, whereas three shifts would each require 56 hours of work over seven days.
A week has 168 hours, and each team’s 56 hours exceed the permitted 48. Furthermore, no one would have a day off or the required 35 consecutive hours of rest.
For continuous operation, 168 hours divided by the 35-hour limit equals 4.8. This means five shifts are needed. Each shift then works 33.6 hours per week on average.
The «3×8, 7 days a week» schedule therefore works out to 5×8. To be open only on Saturdays and Sundays, the substitute teaching team under contract saves you from having to reschedule your week.
How many people are needed per position, including support staff?
A position held continuously requires 5.45 people before absences, and nearly six when absences and training sessions are factored in. The sixth group consists of the reserves, who are not part of the main team and fill in for those who are absent.
You need more than five because a full-time position involves far fewer hours per year than a position that is open day and night. The calculation is done in five steps.
- Count the annual operating hours for the station, which total 8,760 consecutive hours.
- Divide them by 1,607 hours—the annual number of working hours for a full-time employee, excluding vacation time—which equals 5.45 continuously.
- Divide that figure again by 1 minus your absenteeism and training rate, which brings the full-time equivalent to 5.7 to 5.9 people.
- If you don't have your own figures, start with the’Work Absence Monitoring Center : In 2024, downtime accounted for approximately 4.6 % of working time in manufacturing and construction and 6.5 % among blue-collar workers; then add in your training hours.
- Multiply by the number of positions on a team, then subtract the starting players from each team to get the bench players.
What about a production line operating on a 3×8 schedule from Monday through Friday? The same calculation gives you 3.8 to 4.1 people per shift—a calculation that needs to be redone every year, since the number of weekday holidays varies.
Involved from the very beginning, the next generation is also taking shape before the need arises, since she has to be proficient in several positions and few operators are proficient in two.
How many people does it take to run your production line?
The steps in this section, applied to your numbers.
Hours to be covered per position0
Number of people per position0
Total workforce0
Including0
Method: annual operating hours ÷ 1,607 hours ÷ (1 − absenteeism and training rate) × positions per shift; continuous: 8,760 hours per year. Reference: In 2024, work stoppages accounted for approximately 4.6 % of time in manufacturing and construction, and 6.5 % among blue-collar workers; add your training hours.
Example of a 5×8 rotating shift schedule
The most common 5×8 cycle consists of two mornings, two afternoons, two nights, and four days off, over ten days, with five teams staggered by two days.
Since this ten-day cycle doesn't follow the week, the weekends rotate on their own, and Each team works 12 out of every 20 days in ten weeks.
| Team | Day 1 | Day 2 | Day 3 | Day 4 | Day 5 | Day 6 | Day 7 | Day 8 | Day 9 | Day 10 |
|---|---|---|---|---|---|---|---|---|---|---|
| A | M | M | A | A | N | N | R | R | R | R |
| B | R | R | M | M | A | A | N | N | R | R |
| C | R | R | R | R | M | M | A | A | N | N |
| D | N | N | R | R | R | R | M | M | A | A |
| E | A | A | N | N | R | R | R | R | M | M |
This fast rotation is the right one, with just two nights in a row. In its profile What is the recommended rotation schedule?, the INRS advises against doing more than three in a row, as the body clock becomes disrupted after the third one.
The weekly 3×8 shift, on the other hand, involves five consecutive nights and forces the body to readjust every weekend to the family’s schedule, making it the schedule to avoid.
In which direction should the teams rotate?
The teams are taking turns in the sense of morning, afternoon, night. Each shift begins 8 hours later than the previous one, and the operator who finished at 2:00 p.m. returns to work the next day at 2:00 p.m., after 24 hours of rest.
Conversely, the next shift begins 8 hours earlier. After finishing at 10 p.m., the operator returns to work at 6 a.m. after 8 hours of rest—less than the legal requirement of 11 hours and even less than the 9 hours stipulated in a collective bargaining agreement.
What are the work schedules for 3×8 shifts?
Jobs usually start at 6 a.m., 2 p.m., and 10 p.m.. You're under no obligation to do so. You can schedule your shift to coincide with public transportation in your area.
Don't start the morning before 6 a.m., because getting up later reduces sleep debt. Also, make sure to set aside time for a handoff so that safety instructions are passed on.
What should we do with six people per position?
With six people per shift, you maintain the same rotation and Add a rest day to the cycle, which is extended to twelve days.
This is the rounded figure of 5.7 to 5.9 people per position. Each person works 32.7 hours per week, and every other day, a substitute comes in to cover for them or receive training.
Draw your bearing and check it
Select a shift, a start date, and the start time for the morning shift: the calendar and checks will update.
M = morning, A = afternoon, N = night, J = 12-hour shift, L = relief shift, R = rest; holidays are highlighted in the header.
Regulations: 11 hours of rest between shifts (Art. L3131-1), no more than 6 working days (L3132-1), an average of 35 hours in a row (L3132-15), no more than 3 consecutive nights (INRS recommendation). The schedule does not replace either the collective bargaining agreement or the opinion of the CSE.
Rules for rest and nighttime that you should check based on your cycle
Your cycle must include at least two rest days, 11 hours between shifts and 35 hours each week. The table lists the other thresholds and their corresponding articles, which can be reviewed in the Digital Labor Code.
The night has its own ceilings. Without an agreement, it runs from 9 p.m. to 6 a.m., and your shift workers quickly become night workers with shorter shifts.
| Rule | Threshold | Section of the Labor Code |
|---|---|---|
| Break between shifts | 11 hours, 9 hours at a minimum as agreed | L3131-1, D3131-6 |
| Weekly Rest | 35 consecutive hours, no more than 6 working days | L3132-1, L3132-2 |
| Job Duration | 10 hours, 12 hours as agreed | L3121-18, L3121-19 |
| Week | 48 hours, 44 hours on average over 12 weeks | L3121-20, L3121-22 |
| Night Shift Worker Position | 8 o'clock | L3122-6 |
| A Night Worker's Week | An average of 40 hours over 12 weeks, 44 hours as agreed | L3122-7, L3122-18 |
| Successive Teams in a Continuous Cycle | 35 hours worked per week, on average over the year | L3132-15 |
| Pause | 20 minutes after 6 hours of work | L3121-16 |
| Physical Demandingness (C2P) | 30 nights a year, with at least one hour between midnight and 5 a.m. | D4163-2 |
The decision to start a night shift is made by collective agreement. Otherwise, the employer must have negotiated in good faith with the unions and then obtained authorization from the labor inspectorate.
Figure 2. The three shifts over a 24-hour period
When do the legally defined nighttime hours and the time period considered arduous end?.
Shifts in a 3x8 rotation
Night work, 9 p.m.–6 a.m., without an agreement
Midnight to 5 a.m. shift, counted toward the workplace prevention account
| Position | Legal Night Hours | Hours between midnight and 5 a.m. |
|---|---|---|
| Morning: 6:00 a.m.–2:00 p.m. | 0 | 0 |
| Afternoon: 2:00 p.m.–10:00 p.m. | 1 | 0 |
| Night: 10 p.m.–6 a.m. | 8 | 5 |
Labor Code, Articles L3122-2 and L3122-20 (night shift), D4163-2 (occupational safety account: 30 nights per year, with at least one hour between midnight and 5 a.m. in alternating successive shifts). Updated: October 2026.
Before adding a name to the night shift roster, make sure to the employee's consent. The Court of Cassation requires this for the transition from day to night, even with a mobility clause.
A schedule change should be announced in advance seven days in advance, or within the timeframe specified in your agreement. If no agreement has been reached, allow seven business days. The CSE provides its opinion before a decision is made, based on a cycle that has already been verified.
Fill every critical position on every team
Every team needs a'At least two independent individuals at each critical workstation, plus one in training. In a 5x8 schedule, that makes for eleven people trained for the position.
A critical position shuts down the line when it is unstaffed, or requires certification such as the CACES. At night and on weekends, the team operates on its own, and if its sole line operator is absent without a trained replacement, the line shuts down or a coworker is called back from their break.
Of the 98 sites categorized by sector, the median proportion of positions staffed by fewer than three employees ranges from 24.8 % (pharmaceuticals) to 77.8 % (automotive). In a 5x8 shift schedule, each site leaves three or more shifts understaffed.
With only one independent worker, the position becomes vacant the first time that worker is absent. In a 3x8 schedule, seven trained workers are therefore needed per critical position—two per shift and one on standby—and eleven when switching to a 5x8 schedule.
- List the critical positions—those that halt production and those that require authorization.
- In each team, count the number of people who can work independently and have a valid security clearance.
- Aim for two self-sufficient individuals per team and one in the pipeline for each critical position.
- First, move one person from a well-staffed team to an understaffed team—this is faster than training someone.
- Spread out the recycling tasks among the teams, following the deadlines in your authorization matrix.
We recommend forming teams based on the versatility matrix, which determines who is qualified for which position, before considering seniority or personal connections.
Training sessions are getting underway before publishing the cycle, because in this sample, the median time to validate a skill ranges from 8 days (automotive) to 57 days (cosmetics). Versatility becomes a real successor.
Are your critical positions filled on every team?
For each critical position, enter the number of independent and authorized personnel per shift. Pre-filled example: a 5x8 shift schedule.
Target: Two qualified individuals per team and one backup at each critical position. Count only those with valid clearances as of the cycle’s publication date.
In what order should you fill in for someone who is absent?
Replacement for an absent person follows a rule established before the first absence, a fact known to all team leaders, because at night, the decision-maker is on his own.
What about the days when there's no relief? This schedule is mainly for those days, and they work every other day in a rotation of six people per shift.
- A contract worker from the same team, reassigned from a less critical position.
- The next shift, if it's a day shift that day.
- An employee called back from time off, provided that his or her 11 hours of rest and maximum of 6 working days allow it.
- A temporary worker who has already been trained for the position—never a newcomer to a critical position.
Limit the number of nights and weekends outside the regular schedule, and offer them first to the volunteers. A 12-month cycle is easier to manage because everyone knows their schedule in advance.
A A spreadsheet is all you need to draw a cycle. It no longer shows you who can cover for whom when skills, authorizations, and daily absences overlap within the same team.
The Work Schedule at Weiss
The Weiss Chocolate Factory showcases its digitized production schedule on the factory floor.
Before implementing the system, Bonduelle managed its schedules using 25 Excel files, with no visibility into maximum working hours or rest periods. The Bonduelle Case describes the transition to shared scheduling.
The assignment schedule Mercateam handles this process. It provides a qualified, authorized, and available replacement, even from another team.
Where to start this week
Start by the tightest line, the one where you call operators back from their time off. Before making any changes to the schedule, count the number of independent workers on each team for each critical position in the schedule matrix.
Just one hour with your team leaders is enough to determine whether your gaps stem from the process or from skills, and a staff scheduling software Being connected to the matrix then saves you from having to count them.
Assign the right skills to each team
Mercateam's staffing schedule assigns qualified and authorized operators to each position, taking into account shifts and absences.
