Docs
Docs for timetable constraints
Problem-first recipes for teacher, lesson, room, class, and validation constraints, plus a product reference area as Smootables docs expand.
Juho Isola, Smootables founder
Each recipe answers one scheduling question in plain language: what the problem means, what usually causes it, and what to check next in your timetable data. Steps work in any system, whether you plan in a spreadsheet, legacy software, or Smootables.
Product reference pages will document Smootables screens as they ship. For deeper planning theory, use Learn. For free calculators and converters, use Tools.
Constraint recipes
Short, practical answers when one constraint or validation error is blocking your timetable.
Teacher constraints
Minimize teacher gaps in a school timetable
A free period between two lessons is usually a workload issue, not a clash. Here is how to shrink gaps without breaking availability or room rules.
Read recipeCap a teacher's lessons per day
A daily lesson cap stops one teacher from carrying too much of the week on a single day. Check weekly totals and availability before you tighten the cap.
Read recipeModel teacher availability and unavailable periods
Separate periods a teacher cannot work from periods they would rather avoid. Mixing the two is a common cause of impossible timetables.
Read recipeSchedule part-time teachers on fixed days
Fixed working days remove whole days from the placement set. Check whether assigned lessons still fit in the days that remain.
Read recipeLimit consecutive lessons for teachers
A consecutive-lesson cap stops long teaching runs without a break. Balance it against double periods, labs, and daily workload.
Read recipe
Lesson placement
Schedule double-period or block lessons
Double periods need two adjacent slots with the same teacher, class, and room. Plan them before flexible single lessons.
Read recipeSpread subject lessons across the week
Spread rules stop a subject from landing on too few days. They improve pacing but can fight blocks and narrow availability.
Read recipeAvoid two lessons of the same subject on one day
This rule stops repeat lessons of one subject on the same day unless the curriculum needs a block or double period.
Read recipe
Rooms and equipment
Schedule workshops with limited stations or benches
A workshop can be free in the timetable and still unusable if students outnumber stations. Count benches, bays, and machines.
Read recipeRestrict rooms by subject or activity type
Chemistry needs a lab; food technology needs a kitchen. Separate must-have room types from nice-to-have preferences.
Read recipeSchedule lab blocks without room clashes
A lab block needs two adjacent periods and a lab that fits the whole class. Check the full block before you move one period.
Read recipe
Classes and groups
Split a class into subgroups for parallel lessons
Subgroup splits divide one class into smaller groups. Define who is in each group before you place parallel lessons.
Read recipeSchedule team-taught lessons with two teachers
Team-taught lessons need every assigned teacher free in the same period, plus the class and room.
Read recipe
Validation errors
What to do when lessons exceed the maximum possible
This error means the week does not have enough teaching slots for the lessons you configured. Fix the counts before you tune preferences.
Read recipeWhat to do when a teacher is double-booked
One teacher cannot teach two classes at the same time. Trace both lessons, then move, restaff, or remove the duplicate.
Read recipeWhat to do when a room is assigned twice
Two lessons cannot use the same room at the same time unless you deliberately share the space and model it that way.
Read recipe
See how Smootables fits your school's constraints
Book a walkthrough. We will review your teacher load, rooms, and scheduling rules and show how they work in Smootables.