Minutes worked per period

There are different techniques for managing employees' working hours.

For different scenarios see Work limits.

This guide shows you how to manage employees' hours with minutes worked per period. A period can be defined as a week, month, or the entire schedule.

Prerequisites

To run the examples in this guide, you need to authenticate with a valid API key for the Employee Shift Scheduling model:

Log in to Timefold Platform: app.timefold.ai
From the Dashboard, click your tenant, and from the drop-down menu select Tenant Settings, then choose API Keys.
Create a new API key or use an existing one. Ensure the list of models for the API key contains the Employee Shift Scheduling model.

In the examples, replace <API_KEY> with the API Key you just copied.

1. Define minutes worked in a rolling window rules

Period rules are defined in contracts:

{
  "contracts": [
    {
      "id": "partTimeContract",
      "periodRules": [
        {
          "id": "Max8HoursPerDay",
          "period": "DAY",
          "satisfiability": "REQUIRED",
          "minutesWorkedMax": 480
        },
        {
          "id": "Max32HoursPerWeek",
          "period": "WEEK",
          "satisfiability": "REQUIRED",
          "minutesWorkedMax": 1920
        }
      ]
    }
  ]
}

Period rules define how many minutes employees work in a given period. For instance, 480 minutes (8 hours) per day or 1,920 minutes (32 hours) per week.

PeriodRules must include an ID.

period sets the period the rule applies to, for instance, DAY, WEEK, MONTH, SCHEDULE.

Further information about period:

DAY spans a single day and occurs every day in the schedule.

WEEK spans 7 days and occurs every week (including partial weeks) in the schedule. The default start of the week is Monday, but this can be overridden to any day in the week:

{
  "scheduleParameterization": {
    "weekStart": "THURSDAY"
  }
}

MONTH spans the entire month. MONTH has a variable number of days depending on the days in the month and occurs every month (including partial months) in the schedule.

SCHEDULE spans the entire schedule.

You can define custom periods to apply to this rule in the following way:

{
  "scheduleParameterization": {
    "periods": [
      {
        "id": "PAY_PERIOD",
        "dateSpans": [
          {
            "start": "2023-01-01",
            "end": "2023-01-15"
          }
        ]
      }
    ]
  }
}

The start and end dates are inclusive.

minutesWorkedMax sets the limit on how many minutes the employee can work in the specified period.

In some situations it is necessary to specify rules that apply to both the day and the week.

If a rule for the week is included that sets a maximum number of hours per week at 40, but no rule is included for the day period, an employee could be assigned continuous shifts for 40 hours and then nothing for the rest of the week.

Similarly, if a rule is included that sets a maximum number of hours per day at 8, but no rule is included for the week, an employee could be assigned an 8-hour shift every single day with no days off.

periodRules can include or exclude shifts based on shift tags.

{
  "periodRules": [
    {
      "id": "Max8HoursPerDay",
      "period": "DAY",
      "satisfiability": "REQUIRED",
      "includeShiftTags": ["Part-time"],
      "shiftTagMatches": "ALL",
      "minutesWorkedMax": 480
    }
  ]
}

Further information about including or excluding shifts with shift tags:

Shifts with specific tags can be included or excluded by the rule. Tags are defined in shifts:

{
  "shifts": [
    {
      "id": "2027-02-01",
      "start": "2027-02-01T09:00:00Z",
      "end": "2027-02-01T17:00:00Z",
      "tags": ["Part-time"]
    }
  ]
}

Use includeShiftTags to include shifts with specific tags or excludeShiftTags to exclude shifts with specific tags.

shiftTagMatches can be set to ALL or ANY. The default behavior for shiftTagMatches is ALL, and if omitted, the default ALL will be used.

The rule can define either includeShiftTags or excludeShiftTags, but not both.

{
  "includeShiftTags": ["Part-time", "Weekend"],
  "shiftTagMatches": "ALL"
}

With shiftTagMatches set to ALL, all tags defined by the rule’s includeShiftTags attribute must be present in the shift. With shiftTagMatches set to ANY, at least one tag defined by the rule’s includeShiftTags attribute must be present in the shift.

{
  "excludeShiftTags": ["Part-time", "Weekend"],
  "shiftTagMatches": "ALL"
}

With shiftTagMatches set to ALL, all tags defined by the rule’s excludeShiftTags attribute cannot be present in the shift. This is useful when you want to exclude things in combination with each other. For instance, excluding the shift tags Part-time and Weekend with shiftTagMatches set to All, will exclude shifts that include the tags Part-time and Weekend from the rule. Shifts tagged only Part-time or only Weekend will not be excluded.

With shiftTagMatches set to ANY, any of the tags defined by the rule’s excludeShiftTags attribute cannot be present in the shift. This is useful when you need to exclude tags regardless of their relationship to other tags. For instance, excluding the shift tags Part-time and Weekend with shiftTagMatches set to ANY, will exclude any shift that includes the tags Part-time or Weekend, whether they occur together or not.

Each employee must specify which contracts apply to them:

{
  "employees": [
    {
      "id": "Ann",
      "contracts": [
        "partTimeContract"
      ]
    }
  ]
}

The satisfiability can be REQUIRED or PREFERRED. If omitted, REQUIRED is the default.

2. Required minutes worked in a rolling window

When the satisfiability of the rule is REQUIRED, the Minutes worked per period not in required range for employee hard constraint is invoked, which makes sure the number of minutes worked does not exceed the limit specified in minutesWorkedMax.

Shifts will be left unassigned if assigning them would break the Minutes worked per period not in required range for employee constraint.

In the following example, there are 5 shifts, 1 employee, and a rule with a required satisfiability that specifies the employee can work at most 1,920 minutes (32 hours) per week.

4 shifts, totaling 1,920 minutes, are assigned and 1 shift is left unassigned to avoid breaking the Minutes worked per period not in required range for employee hard constraint.

Input
Output

Try this example in Timefold Platform by saving this JSON into a file called sample.json and make the following API call:

curl -X POST -H "Content-type: application/json" -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules [email protected]

{
  "config": {
    "run": {
      "name": "Required minutes worked per period example"
    }
  },
  "modelInput": {
    "contracts": [
      {
        "id": "partTimeContract",
        "periodRules": [
          {
            "id": "Max8HoursPerDay",
            "period": "DAY",
            "satisfiability": "REQUIRED",
            "minutesWorkedMax": 480
          },
          {
            "id": "Max32HoursPerWeek",
            "period": "WEEK",
            "satisfiability": "REQUIRED",
            "minutesWorkedMax": 1920
          }
        ]
      }
    ],
    "employees": [
      {
        "id": "Ann",
        "contracts": [
          "partTimeContract"
        ]
      }
    ],
    "shifts": [
      {
        "id": "Mon",
        "start": "2027-02-01T09:00:00Z",
        "end": "2027-02-01T17:00:00Z"
      },
      {
        "id": "Tue",
        "start": "2027-02-02T09:00:00Z",
        "end": "2027-02-02T17:00:00Z"
      },
      {
        "id": "Wed",
        "start": "2027-02-03T09:00:00Z",
        "end": "2027-02-03T17:00:00Z"
      },
      {
        "id": "Thu",
        "start": "2027-02-04T09:00:00Z",
        "end": "2027-02-04T17:00:00Z"
      },
      {
        "id": "Fri",
        "start": "2027-02-05T09:00:00Z",
        "end": "2027-02-05T17:00:00Z"
      }
    ]
  }
}

To request the solution, locate the 'ID' from the response to the post operation and append it to the following API call:

curl -X GET -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules/<ID>

{
  "run": {
    "id": "ID",
    "name": "Required minutes worked per period example",
    "submitDateTime": "2025-03-31T06:35:05.908682739Z",
    "startDateTime": "2025-03-31T06:35:21.38159037Z",
    "activeDateTime": "2025-03-31T06:35:21.634093236Z",
    "completeDateTime": "2025-03-31T06:40:22.536142384Z",
    "shutdownDateTime": "2025-03-31T06:40:22.832585412Z",
    "solverStatus": "SOLVING_COMPLETED",
    "score": "0hard/-1medium/0soft",
    "tags": [
      "system.profile:default"
    ],
    "validationResult": {
      "summary": "OK"
    }
  },
  "modelOutput": {
    "shifts": [
      {
        "id": "Mon",
        "employee": "Ann"
      },
      {
        "id": "Tue",
        "employee": "Ann"
      },
      {
        "id": "Wed",
        "employee": "Ann"
      },
      {
        "id": "Thu",
        "employee": "Ann"
      },
      {
        "id": "Fri",
        "employee": null
      }
    ]
  },
  "inputMetrics": {
    "employees": 1,
    "shifts": 5,
    "pinnedShifts": 0
  },
  "kpis": {
    "assignedShifts": 4,
    "unassignedShifts": 1,
    "workingTimeFairnessPercentage": null,
    "disruptionPercentage": 0.0,
    "averageDurationOfEmployeesPreferencesMet": null,
    "minimumDurationOfPreferencesMetAcrossEmployees": null,
    "averageDurationOfEmployeesUnpreferencesViolated": null,
    "maximumDurationOfUnpreferencesViolatedAcrossEmployees": null,
    "activatedEmployees": 1,
    "assignedMandatoryShifts": 4,
    "assignedOptionalShifts": 0,
    "travelDistance": 0
  }
}

modelOutput contains the schedule with 4 shifts (1,920) minutes assigned and 1 shift unassigned.

inputMetrics provides a breakdown of the inputs in the input dataset.

KPIs provides the KPIs for the output including:

{
  "assignedShifts": 4,
  "unassignedShifts": 1,
  "activatedEmployees": 1,
  "assignedMandatoryShifts": 4
}

3. Preferred minutes worked in a rolling window

When the satisfiability of the rule is PREFERRED, the Minutes worked per period not in preferred range for employee soft constraint is invoked.

With a satisfiability of PREFERRED a minutesWorkedMin value can also be provided to set the preferred minimum number of minutes worked.

{
  "contracts": [
    {
      "id": "partTimeContract",
      "periodRules": [
        {
          "id": "Min2HoursMax8HoursPerDay",
          "period": "DAY",
          "satisfiability": "PREFERRED",
          "minutesWorkedMin": 120,
          "minutesWorkedMax": 480
        },
        {
          "id": "Min16Max32HoursPerWeek",
          "period": "WEEK",
          "satisfiability": "PREFERRED",
          "minutesWorkedMin": 960,
          "minutesWorkedMax": 1920
        }
      ]
    }
  ]
}

Shifts will be assigned to employees even if the shifts take the employees minutes worked over the limit specified by minutesWorkedMax or under the limit specified by minutesWorkedMin, however, this constraint adds a soft penalty to the run score for any matches to the constraint, incentivizing Timefold to find an alternative solution.

In the following example, there are 5 shifts, 1 employee, and a rule with a preferred satisfiability that specifies the employee should only work 1920 minutes (32 hours) per week.

All 5 shifts are assigned, totaling 2,400 minutes, and a soft penalty is applied to the score run.

Input
Output

Try this example in Timefold Platform by saving this JSON into a file called sample.json and make the following API call:

curl -X POST -H "Content-type: application/json" -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules [email protected]

{
  "config": {
    "run": {
      "name": "Preferred minutes worked per period example"
    }
  },
  "modelInput": {
    "contracts": [
      {
        "id": "partTimeContract",
        "periodRules": [
          {
            "id": "Max8HoursPerDay",
            "period": "DAY",
            "satisfiability": "PREFERRED",
            "minutesWorkedMax": 480
          },
          {
            "id": "Max32HoursPerWeek",
            "period": "WEEK",
            "satisfiability": "PREFERRED",
            "minutesWorkedMax": 1920
          }
        ]
      }
    ],
    "employees": [
      {
        "id": "Ann",
        "contracts": [
          "partTimeContract"
        ]
      }
    ],
    "shifts": [
      {
        "id": "Mon",
        "start": "2027-02-01T09:00:00Z",
        "end": "2027-02-01T17:00:00Z"
      },
      {
        "id": "Tue",
        "start": "2027-02-02T09:00:00Z",
        "end": "2027-02-02T17:00:00Z"
      },
      {
        "id": "Wed",
        "start": "2027-02-03T09:00:00Z",
        "end": "2027-02-03T17:00:00Z"
      },
      {
        "id": "Thu",
        "start": "2027-02-04T09:00:00Z",
        "end": "2027-02-04T17:00:00Z"
      },
      {
        "id": "Fri",
        "start": "2027-02-05T09:00:00Z",
        "end": "2027-02-05T17:00:00Z"
      }
    ]
  }
}

To request the solution, locate the 'ID' from the response to the post operation and append it to the following API call:

curl -X GET -H 'X-API-KEY: <API_KEY>' https://app.timefold.ai/api/models/employee-scheduling/v1/schedules/<ID>

{
  "run": {
    "id": "ID",
    "name": "Preferred minutes worked per period example",
    "submitDateTime": "2025-05-23T04:28:00.33365481Z",
    "startDateTime": "2025-05-23T04:28:11.482387879Z",
    "activeDateTime": "2025-05-23T04:28:11.680636874Z",
    "completeDateTime": "2025-05-23T04:28:42.436311376Z",
    "shutdownDateTime": "2025-05-23T04:28:42.689771356Z",
    "solverStatus": "SOLVING_COMPLETED",
    "score": "0hard/0medium/-960soft",
    "tags": [
      "system.profile:default"
    ],
    "validationResult": {
      "summary": "OK"
    }
  },
  "modelOutput": {
    "shifts": [
      {
        "id": "Mon",
        "employee": "Ann"
      },
      {
        "id": "Tue",
        "employee": "Ann"
      },
      {
        "id": "Wed",
        "employee": "Ann"
      },
      {
        "id": "Thu",
        "employee": "Ann"
      },
      {
        "id": "Fri",
        "employee": "Ann"
      }
    ]
  },
  "inputMetrics": {
    "employees": 1,
    "shifts": 5,
    "pinnedShifts": 0
  },
  "kpis": {
    "assignedShifts": 5,
    "unassignedShifts": 0,
    "disruptionPercentage": 0.0,
    "activatedEmployees": 1,
    "assignedMandatoryShifts": 5,
    "assignedOptionalShifts": 0,
    "travelDistance": 0
  }
}

modelOutput contains the schedule with all 5 shifts assigned to Ann.

inputMetrics provides a breakdown of the inputs in the input dataset.

KPIs provides the KPIs for the output including:

{
  "assignedShifts": 5,
  "activatedEmployees": 1,
  "assignedMandatoryShifts": 5
}

See the full API spec or try the online API.
Learn more about employee shift scheduling from our YouTube playlist.
See other options for managing employees' work hours: Work limits.

Minutes worked per period

Prerequisites

1. Define minutes worked in a rolling window rules

2. Required minutes worked in a rolling window

3. Preferred minutes worked in a rolling window

Next