How to Build a School Timetable: A Step-by-Step Guide

School starts in a week. On the deputy head's desk: the teacher list, the classes and a pile of notes. “Ms. Aydın can't come on Fridays.” “The physics lab is taken on Tuesday mornings.” “Maths in double periods.” All true, all important. The trouble is that all of it has to be true at the same time.

A timetable is a puzzle whose pieces change every year. The good news: build it in the right order and it gets much easier. The steps below are how a timetable is built in Atlas, in order. The same order works on paper too.

1. First the frame: days and periods

Everything starts with the bell schedule. Which days have lessons, how many periods a day, where the breaks and lunch fall. In Atlas you set this up on the Days / Periods screen. A period can exist only on some days, for example no seventh period on Friday, and days can have their own clock times.

The order of the periods is the real frame of the timetable. Clock times (09:10, 10:00) appear on the printouts; Atlas places lessons by the order of the periods.

2. Teachers, classes, subjects and rooms

Next comes the school itself: under Definitions, teachers, classes, subjects and classrooms. If your lists are in Excel you don't need to retype them; you can import them from an Excel or CSV file.

Give each classroom a category. The categories in Atlas are General / Classroom, Lab, Gym, Library, Auditorium, Workshop, Cafeteria, Yard and Other. When a lesson needs a lab, Atlas places it only in a room of that category with enough capacity.

3. Lesson requirements: who, which class, how many hours

The real content of a timetable is its lesson requirements: which class, which subject, which teacher, how many hours a week. For each one you also choose how the weekly hours are split:

• Single: every hour on its own.
• Double: blocks of two (2+2+1 for five hours).
• Mixed: blocks of three first, then two.
• Custom pattern: your own, for example 2+1+1+1. A session is 1 to 3 periods long.

If several teachers teach a lesson together you pick them all, and all of them are busy in that period. Lessons that several classes take together at the same time are set up as a shared lesson. Block lessons have a post of their own: What is a block lesson, and how is it placed?

4. The school's rules: required and preferred

Every school has its own rules. In Atlas a rule is either a required rule or a preference. A required rule is never broken. Preferences get a Low, Medium or High priority, and Atlas meets them as far as it can. A few of the rules schools use most:

• Teachers' and classes' hours, on the Availability tab: Available, Discouraged, Closed. No lesson is ever placed in a closed period.
• Keep one day free for a teacher. More: How to plan a teacher's day off
• Spread a lesson evenly across the week and Schedule heavy subjects earlier in the day. More: How to spread weekly hours across the days
• Not on the same day, At the same time, Before–after order: where two lessons sit relative to each other.
• Synchronized lesson: the selected classes take the same subject on the same day and period.

5. Before building: the pre-check

When you press Generate Timetable, Atlas first runs a pre-check. Some problems are clear before any timetable is tried. If a teacher has more lessons than open periods, or a block lesson has no run of consecutive periods to fit in, Atlas says so up front. The headings look like: “Teacher availability is insufficient”, “No consecutive window for the block”, “Room category capacity is insufficient”.

The pre-check finds two kinds of things. A blocker must be fixed before a timetable can be built. A warning doesn't stop the build; it tells you about something that may strain the timetable's quality.

6. Build the timetable

If the pre-check is clean, Atlas builds the timetable: no teacher in two classes at once, no room given twice in the same period, every required rule kept. The same input always gives the same result. If no timetable exists under these rules, Atlas says so plainly and shows why. We wrote about that separately: What to do when the timetable won't build

7. Edit, lock, save as a version

A built timetable is not the end. You can drag a lesson to another period; Atlas checks the change before saving it and, if it breaks a rule, tells you which one. A lesson you Lock stays where it is. Save as version the one you like and compare it with another. More: How to change a timetable without clashes

8. Share it

The last step is getting the timetable to everyone. You can view it by class, teacher and room, and as a master sheet. Print it on A5, A4 or A3, or download it as PDF or Excel. The published version can also be emailed to teachers. More: Master timetables and teacher schedules

All of this is summarised on the Atlas school timetabling page, and the part that builds the timetable for you on the automatic timetable generator page. To try it with your own school, start a 7-day free trial; no card needed.