Part-time teachers in the timetable: days off, gaps and fair rules

A part-time teacher timetable works when a handful of decisions are made before the first run, not after it. In short: collect every part-timer's working days and blocked times on one form by a fixed date; treat the days in the contract as fixed and almost everything else as a preference; agree how many days in school a given share of the week means; keep part-timers' days compact, because a gap costs them a larger share of their week; count meetings, duties and cover in proportion; check the arithmetic (lessons against usable slots) before you solve; and tell anyone whose wish could not be met before the timetable is published, with the reason.

This post is about part-time staff. The general trade-off between teacher and class gaps is in Teacher gaps, student gaps; finding impossible combinations before a run in Why timetables become impossible.

What makes a part-time teacher timetable different

• The days are often in the contract. In maintained schools in England, the STPCD 2026 (paragraph 52.9) says a part-timer may not be required to be available for work on a day, or part of a day, they do not normally work. Elsewhere an agreement or a state rule fixes them. Either way, they are not a wish to trade away in July.
• Every blocked day narrows other people's weeks. If Year 10's only chemistry teacher works Monday to Wednesday, Year 10's whole week arranges itself around that.
• Fixed costs weigh more. A free period, a meeting or a duty costs the same minutes whatever the contract; out of 13 lessons instead of 25, they are a bigger share of the week.

Part-time teachers' days off: a fixed day or "any three days"?

This decision has the largest effect. With "Friday off", every lesson the teacher gives, in every class, must fit into four days. With "any three days", the timetable chooses the days that suit the classes, and usually finds a better week for everyone. It gets harder when four part-timers all want Friday, or Monday. So ask two questions on the form: which days the contract fixes, and whether a preferred day is negotiable. The DfE's guidance on flexible working in schools (updated 26 October 2026) says an employee who wants to work part time "could be flexible about their non-working days".

In Bildena both are entered in the teacher wizard, step Availability. A fixed day off is a whole day painted Not available (✕); the solver never places a lesson there. "Any three days" is Max days per week set to 3, which counts days with at least one lesson; the solver picks which. Both are hard limits.

A 0.5 teacher on how many days?

A share of the week does not say how many days. Take a five-day week with six periods a day (30 slots) and a full-time timetable of 25 lessons. A teacher on 0.5 teaches 12 or 13 lessons. Spread over five short days, they come in every day for two or three lessons; packed into two long days, they teach six or seven lessons a day and have no room to move.

Some German states write a rule down, and the rules make useful starting points anywhere. Lower Saxony gives a teacher whose hours are reduced by at least a third at least one teaching-free day a week, and no days with fewer than two lessons from a one-fifth reduction. Brandenburg plans a teaching-free day from a 25 % reduction, if the teacher wants one, and asks schools to avoid days with fewer than three lessons and days with both morning and afternoon lessons. A regional authority in North Rhine-Westphalia (Cologne, 2018) recommends this:

Then check the slack, which is what the timetable needs to make everyone else's week work. A 0.6 teacher has 15 lessons. On three fixed days of six periods there are 18 slots for 15 lessons: three to spare, and every class she teaches must fit her subject into those three days. On four days there are 24 slots for 15 lessons, nine to spare, and three or four lessons a day, which also stays clear of Brandenburg's three-lesson floor. The more slack, the fewer compromises for her classes.

In Bildena the wizard's Teaching step has a field Contract lessons per week. It is information, not a constraint: the solver places the lesson cards the teacher has, and the wizard shows the lessons against the contract ("2 below contract"). The wizard does not let you past Availability while fewer slots are usable (Available or Only if needed) than the contract has lessons. Its limits are Max lessons per day and Max days per week. It has no field for a minimum number of lessons on a working day, and no rule against morning-and-afternoon days; if those matter to you, check them in the finished plan.

Gaps cost part-timers more

Three free periods in a week are a nuisance for a full-timer with 25 lessons: about 12 % on top of their teaching time. For a colleague on 13 lessons the same three gaps are 23 %, nearly twice the share. That is why Brandenburg asks for free periods in proportion to the part-time rate, and why Lower Saxony, in all-day schools, rules out gaps for teachers with at least a one-fifth reduction unless they want them.

Watch the blocked periods in the middle of a day. If a teacher cannot teach Tuesday periods 3 and 4 (a second school, a regular appointment) and teaches periods 2 and 5, those two blocked periods are two gaps in school. "Mornings only" or "from period 3" usually produce a better week than a hole in the middle.

In Bildena Max gaps per day is a hard limit per teacher, and a blocked period between two lessons counts as a gap. Beyond that limit, gaps are a weighted cost, and the weight is one value for the whole school: with the default weights a teacher gap costs 2 points and a class gap 40. The profile Teacher-friendly (under What to Prioritize when you start a run) raises the teacher gap to 8. There is no way to weigh one person's gaps more heavily than another's; to protect a part-timer, set their Max gaps per day to 0 or 1. The Pre-generation Checks warn when that teacher's blocked periods already force more gaps than their limit allows.

Meetings, training days and the meeting afternoon

Fix the meeting slot before you collect wishes. Once the weekly meeting afternoon is known, nobody can be surprised that their preferred day off is the meeting day. In maintained schools in England the STPCD is clear: a part-timer cannot be required to attend non-pupil days on days they do not normally work (it can be agreed, and paid; guidance paragraph 42); duties outside school sessions can be asked only on working days, and only in proportion to the contract (52.10–52.11). Brandenburg goes further and excuses teachers below 80 % from conferences case by case, unless the topic needs them.

Workable patterns: the meeting after the last period of a day nobody has off; a meeting day that rotates each term; or, agreed in writing, the minutes for those who are not in.

In Bildena there is no single switch that blocks a meeting slot for the whole staff; you block it in each teacher's availability grid, or keep the meeting after the last period. Max days per week counts days with lessons, so a day with only a meeting is not counted as a working day.

Job shares: two teachers, one class

In primary schools a job share usually splits by days (Monday to Wednesday morning, Wednesday afternoon to Friday); in secondary schools more often by subject or group. Decide up front:

• The handover. The DfE guidance calls a full handover essential and encourages employers to fund an overlap between the partners. Put it in the timetable, not in a lunch break.
• The class's first contact, and how parents reach the other partner.
• Whole subjects, not halves. Splitting one subject's weekly hours between two people doubles the coordination.

In Bildena each partner has their own availability grid with their own days off. A handover lesson is a lesson card with a second teacher ticked: both take the lesson together and both are busy that period. The class wizard takes a class teacher and a deputy, so each partner can hold one of them. When one partner is away, cover suggestions rank the class's own teachers high ("Knows the class"). But cover suggestions do not read the availability grid: the partner can appear on their day off, marked "no lessons today" and ranked lower. A person confirms every cover, and that person should know the job share's days.

Duties and cover: count them in proportion

Rules agree on the principle. In England the time a part-timer can be asked for outside sessions is capped at their share (52.11). Lower Saxony deploys part-timers for supervision and cover "only in line with their part-time rate". Germany's Federal Administrative Court ruled in 2015 (2 C 16.14) that part-time teachers may not be drawn on beyond their part-time rate. What a school still has to decide is the method: duties exactly in proportion, or equal per head with a cap for part-timers. More in Break duties: how to share them fairly.

In Bildena the duty plan gives a teacher duties only around the periods they are in school (one period before their first lesson to one after their last), so a free day stays free once a timetable exists. Its fair share is the same for every candidate; a lower load for part-timers is set per person with Max break duties per week, or Exempt. In the Cover ranking, the weight Contract hours puts "teachers under their contract hours first, part-timers spared": a contract below 80 % of the largest in the school marks a teacher "part-time" and moves them down. The fairness weight compares this term's covers with the school average, a plain count not divided by the contract. Never ask, with the reason Part-time that only management sees, takes a teacher off the list; Max covers per week ranks them last once reached.

What to collect from part-time staff, and by when

The DfE suggests asking staff to submit flexible working requests "by a particular date to ensure there is sufficient time to plan the timetable". A statutory request can be made from the first day of employment, up to two in any twelve months, and needs an answer within two months. Count back: the answer has to come before you build next year's timetable. Then send one form to every part-timer, with the same questions for everyone:

1. Contract share and lessons a week, from the contract, not from memory.
2. Working days: fixed by the contract (which), or "any N days".
3. Must-blocked periods: day and period only. The reason goes to the head, not into the timetable.
4. Preferences: a preferred day off, no first or last period, compact days. Marked as preferences.
5. Most lessons in a day they can manage, and the fewest worth coming in for.
6. The meeting slot: can they attend, and if not, what has been agreed.
7. Job share: the partner, the split, the handover.
8. Changes during the year, such as a return to full time in February.

Ask everyone to confirm last year's blocked times again rather than copying them forward: the childcare slot of a child who has started school is a common leftover.

When wishes cannot all be met: hard, soft and an order

Agree the order before the forms come back, and publish it with the form: first what the contract and the law fix (working days, a state rule on free days); then health and disability; then caring for children or relatives; then a part-timer's preferred day; then personal preferences. Everything below the contract line is a preference that the timetable meets where it can.

Then check the arithmetic, teacher by teacher. Mr Adeyemi teaches 16 lessons, wants at most three days and at most five lessons a day: three times five is 15, one short. No timetable can satisfy that, however long it runs, and the sooner you find out the cheaper the conversation.

In Bildena the Pre-generation Checks catch this case: "the per-day/per-week lesson limit cannot cover the assigned total hours" is a critical issue, and critical issues block generation. Fix with AI offers to raise the daily limit to the smallest value that fits (here six a day, which keeps his three days; the days only if that is not enough) or to cut the hours, shows each old and new value, and changes nothing until you apply it. A soft wish is painted Only if needed (?): with the default weights a lesson there costs 3 points, about a teacher gap and far below a class gap, whoever it belongs to. When a run fails on rules the Checks cannot see in advance, the result names them, for example "… — max days per week".

How to tell a part-timer which wish could not be met

Before the timetable is published, in person or in a short note, never first on the noticeboard. One regional authority in Germany asks schools to tell the teacher "as soon as possible" when a timetable wish cannot be met; that is good practice anywhere. Say four things:

• What was not met, exactly: "Tuesday period 1 is taught" rather than "we couldn't do everything".
• Why: which class, which rule, which other wish came first under the published order.
• What was kept: the fixed day, the no-afternoon Wednesday.
• What happens next: priority for that wish next year, written down.

In Bildena the list is ready. Plan › Overview shows, under Changed since publishing, every teacher whose Only-if-needed slots hold a lesson: a line "Wish · " with the teacher's name, and below it, for example, "Tue 1st lesson wished free — still open". Not-available slots are never used, so they never appear there.

What Bildena does not do for part-time staff

It does not read contract lessons when it builds the timetable. It has no per-teacher gap weight, no minimum of lessons per working day in the teacher wizard, no morning-and-afternoon rule and no whole-staff meeting slot. Its duty fair share is equal per head, and cover suggestions do not read blocked days. In England, its PPA Compliance report counts every period without a lesson or duty as free, a part-timer's day off included, while the STPCD asks for PPA of at least 10 % of their timetabled teaching time within the timetabled week (53.4): check part-timers' PPA by hand. When hours change during the year, the timetable can be repaired without starting over: see Change one lesson, keep the rest.

Frequently asked questions

How many days should a 0.5 teacher work?

Usually three or three and a half. Fewer days leave the timetable no room; five short days mean coming in for two lessons. The contract or a state rule comes first.

Can a part-time teacher be asked to come in on a non-working day?

In maintained schools in England, not as a requirement (STPCD 52.9). They can agree to, and the extra time is paid.

Bildena Scheduler starts at €490 per school a year. In the free month you can enter your part-timers' days and blocked times and see what the Pre-generation Checks say before the first run. No card needed.