How to Build a School Timetable and Manage Teacher Cover Fairly

What are the steps to build a school timetable?

A school timetable is a set of decisions about how the curriculum, teachers, students and rooms meet across a repeating cycle. The work goes best in a fixed order, because each step depends on the one before. Here are the eight steps most experienced timetablers follow, in the order they follow them.

• 1. Fix the shape of the cycle: days in the cycle (five, six or ten) and teaching periods per day.
• 2. Agree the curriculum plan: periods per cycle for every subject in every grade, adding up exactly to the cycle.
• 3. Staff it: teacher periods needed per subject, each person's maximum load, and the gap in FTE subject by subject.
• 4. Write the model: option blocks built from students' choices, hard rules that are never broken and soft rules in ranked order.
• 5. Build in sequence: option blocks, part-time staff, specialist rooms and doubles, the most constrained teachers, then everything else.
• 6. Check after every stage: zero teacher, class and room clashes before the next stage begins.
• 7. Publish once: share draft personal timetables for factual errors only, fix them, then publish to everyone on the same day.
• 8. Run and review: rooms, duties, exams and daily cover inside the timetable, every change through one form, and an end-of-year review.

Why should the curriculum plan come before staffing?

If you start from last year's timetable you inherit every compromise made for people who may have left. If you start from the staff you have, the curriculum bends to fit them, and nobody chose the result. Start from what each grade should be taught and for how long.

The plan must add up exactly. On a six-day cycle of eight periods, every class has 48 periods. If a grade's subjects add to 47, a class has an accidental free period; if they add to 49, the timetable cannot be built at all. Add every grade before you go further, and write a short reason beside any number that changed from last year. Treat double periods with suspicion: keep them where a subject genuinely needs a longer block, because each one needs two consecutive free periods for a class, a teacher and a room at once.

How do you calculate how many teachers a timetable needs?

Three numbers do the work. Teacher periods needed for a subject is periods per cycle multiplied by the number of classes or option groups that take it. Each teacher's maximum is your full-time teaching load times their FTE (full-time equivalent), less any reduction for leadership roles. FTE needed is teacher periods needed divided by the full-time load.

Here is an original worked example for a small school with 18 classes on a 40-period week, where a full-time teacher teaches at most 32 periods. Read the gap subject by subject: the total can look comfortable while one subject is short.

• The total gap is only 0.10 FTE, which looks like nothing.
• Mathematics alone is 0.38 FTE short and Humanities 0.25 FTE short: about 12 and 8 periods a week with no qualified teacher.
• Spare English capacity (0.22 FTE) cannot teach Mathematics. The decision is a part-time Mathematics post, or reallocating a qualified colleague, made months before the year starts.

What are hard and soft constraints in timetabling?

Timetabling is usually described as a constraint satisfaction problem: find a place for every lesson that breaks none of the rules. Splitting the rules into two lists makes the job, and the arguments, far easier.

Hard constraints are never broken: no teacher, class or room in two places at once; every class receives its curriculum periods; contracts, agreed part-time days and reasonable adjustments are respected; each teacher keeps at least the minimum planning time that applies to them; practical lessons are in safe, equipped rooms; supervision points are staffed.

Soft constraints are wishes in a written order: subjects spread across the cycle, the widest fair option choice, few teachers per class, non-contact time spread out, short walks between rooms, and staff preferences applied by one rule for everyone. When two soft rules conflict, the higher one wins. Putting the order in a short timetabling policy turns a personal refusal into a policy decision.

In what order should you place lessons?

Place the pieces with the fewest possible positions first. An ordinary single lesson can go almost anywhere; an option block needs several teachers and rooms free at the same moment across a whole grade, and a teacher who works three days a week has far fewer possible slots than a full-timer. If flexible lessons go in first, they fill exactly the slots the inflexible ones needed.

A reliable order is: option blocks and whole-grade lessons; part-time and shared staff; specialist rooms and doubles; the most constrained teachers; then the rest. After each stage, check for clashes and fix them while a fix is still a simple swap. A spreadsheet with one row per lesson can flag a clash on every row by counting how often the same teacher, class or room appears in the same day and period.

How should a school manage daily teacher cover?

Teacher absence is normal. The UK Department for Education's School Workforce in England statistics report that in the 2024/25 academic year 61.8% of teachers took some sickness absence, averaging 8.1 days each among those who did, before training, trips and appointments are counted. Cover is a daily operation, and it works best as a routine with three rules everyone can see.

First, a reporting deadline: a phone call to a named cover line by a set time, early enough to arrange cover before registration. Second, a written priority order, applied the same way every morning. Third, a cap on how many cover lessons a teacher is asked to do each term, pro rata for part-timers, so the same helpful people are not asked every time. Some national conditions limit cover by teachers; in England, for example, the School Teachers' Pay and Conditions Document says teachers should be required to cover only rarely and only in circumstances that are not foreseeable.

What checks do substitute teachers need?

Substitutes, supply teachers, cover supervisors and agency staff sit inside the school's safeguarding structure. What a background check is depends on the country and sometimes the state: in England, Keeping Children Safe in Education sets out safer recruitment and the single central record, and for agency supply staff schools obtain written confirmation from the agency of the checks it has carried out; in Australia each state and territory runs its own Working With Children Check; in India and many other countries police verification or clearance is common, with board and state rules on top.

Whatever applies to you, three practical habits keep cover safe. Keep a status for every substitute (checks confirmed, review date, safeguarding briefing done) and book only people who are clear. Store references and dates in your cover records, and keep certificates in your secure single central record or equivalent. Brief every substitute before their first lesson: who the designated safeguarding lead is, how to report a concern, the code of conduct essentials and the emergency procedures.

What are the most common timetabling and cover mistakes?

• Editing last year's timetable instead of building from this year's curriculum plan.
• Reading the staffing total and missing a subject-level shortfall.
• Placing easy lessons first and leaving option blocks and part-time staff until the end.
• Running specialist rooms at full use, with no slack for practicals or exams.
• Typing changes straight into the system without checking the knock-on effects, then telling only some of the people affected.
• Asking the same reliable teachers for cover because they never refuse.
• Booking a substitute before written confirmation of checks arrives, or skipping the briefing because they have been before.
• Recording medical details in cover or absence logs instead of a category.
• Leaving an absent person's duty uncovered.
• Treating an AI tool's suggestion as an allocation rather than a draft for a person to decide.

Where does AI help with timetabling and cover?

AI assistants are useful for drafting messages and cover work, checking pasted data (adding up a curriculum plan, counting option pairs, scanning a lesson list for clashes), suggesting a first draft of a duties rota or a cover allocation that follows your written rule, and summarising feedback. They should never decide an allocation, and they should never see student names, health details, safeguarding information or background-check records. Check every number a tool gives you against your own records before acting.

If you want the whole method in ready-made files, The School Timetable and Cover Planner from Bodhih Training includes a clash-checking timetable workbook, a staffing calculator, cover and duties policies, a message library and a staffroom print pack. To benchmark your own planning skills, AssessAll's Budget & Resource Allocation Reasoning assessment is a useful starting point, and Jobulary's explainer on the 70-20-10 model shows how to grow a new timetabler's skill through real tasks with feedback.