Key takeaways
- A hard constraint must always hold, like no teacher or group double-booked; a soft constraint is a preference the plan can trade off once the hard rules leave no room.
- A manual canvas or template suits a single class and a single teacher, but nothing checks the grid once a second teacher, room, or group enters the picture.
- A spreadsheet holds more data than one page can, but it does not know a hard constraint from a soft one, and checking either is manual arithmetic every time.
- Dedicated timetabling software runs hard constraints as rules, optimises soft constraints as preferences, validates before generating, and can name the reason when a solve turns out infeasible.
Manual canvases and templates
The simplest version: a blank grid, printed or as a PDF or image template, filled in by hand. This is the right tool for a single class run by a single teacher, where the whole timetable fits on one page and in one person's head. There is no software to learn and nothing to configure.
It stops being the right tool the moment a second teacher, room, or group enters the picture, because nothing checks the grid for you. A double booking is only caught when a human happens to look at the right two cells at once, and a kickout, a lesson with nowhere to go because its teacher or students are not simultaneously free, stays invisible until someone tries to actually run the lesson.
Spreadsheets
Most schools past the single-class stage end up here, and for good reason: a spreadsheet holds far more than one page can, and everyone already knows how to open one. The trouble is where the data ends up. Once several people or several campuses are each building a piece of the same plan, the timetable is spread across separate Excel files that then have to be pulled together by hand, and the year's plan has to finish before any actual placement can start.
A spreadsheet does not know the difference between a hard and a soft constraint either. It can hold both, but checking whether a teacher's weekly hours are over the cap, or whether a "musical chairs" style FIT, a chain of small moves that clears space for one stuck lesson, actually works, is manual arithmetic every time. That is fine at small scale and becomes the whole job at larger scale.
Dedicated timetabling software
Software built specifically for this problem treats the hard/soft split as the thing it does, rather than something a person maintains by eye. It runs the hard constraints as rules a plan cannot violate and the soft constraints as preferences it optimises for, and it validates the setup before generating anything, so a doomed attempt fails before it wastes an afternoon rather than after. When a lesson genuinely cannot be placed, this kind of software can name the reason, rather than leaving someone to work out which interacting constraint is the actual blocker.
This is also the category built to handle the cases that break the group-shaped assumption underneath a simple grid: a vocational programme where a workshop has a fixed number of stations and cohorts rotate through them, or a placement block that sends students off-site for a day or two a week. Neither fits neatly into the whole-class, single-room model a simple grid assumes, and a spreadsheet has no native way to represent either beyond a manual note.
Which method fits which process
The tool question and the process question are really one question, because the process decides who is doing the checking.
Teachers build their own timetable, in full. This is the manual-canvas or single-sheet case: one person, one scope, nothing to consolidate. A template or a simple spreadsheet is proportionate here; the coordination problem the other methods solve does not exist yet.
Teachers draft, and a planner consolidates. This is where a shared spreadsheet starts to strain, because the planning phase is not standardized across planners or campuses at this stage, and quality and timing end up depending on which person happens to be doing the consolidating. Consolidation is exactly the moment a hard-constraint clash between two people's drafts, each plausible on its own, only shows up once someone combines them, and combining them by hand is where the real hours go.
Planners build the whole timetable themselves, teachers mostly supply preferences. This is the fullest coordination load, and the one where dedicated software earns its keep the most: one person now holds every teacher's hour ceiling and the curriculum's dependencies at once, on top of every room's availability, which is exactly the job a constraint solver is built to carry instead.
Cost efficiency here is not really about licence price. Nothing about our own pricing is settled or published yet. The real cost is whose time the coordination step consumes: a manual grid or a spreadsheet costs time in proportion to how many people and constraints touch the plan, and that cost grows with scale, while a solver's checking does not.
Where Smootables fits into this
For the software category above, Smootables is one example: the solver separates 11 hard constraint families from 6 weighted soft preferences, validates a plan before generating it, and names the reason when a solve turns out infeasible instead of failing silently. Whether that shape suits your school depends on which of the three processes above you are actually running.
If you want to see the solver itself in action, how the automatic timetable solver works goes through it in more detail. If you are already weighing named tools against each other, the software comparison is the more useful next stop than this page.
Questions planners ask about choosing a timetabling method
What's the difference between a hard constraint and a soft constraint?
A hard constraint must always hold, for example no teacher or group double-booked, or nobody over a weekly hour ceiling, or the plan does not count as usable. A soft constraint, like a teacher's preferred free period or spreading a subject evenly across the week, is a preference the plan tries to honour but can trade off once the hard rules leave no room.
When is a template or spreadsheet enough to build a school timetable?
A manual canvas or template suits a single class run by a single teacher, where the whole timetable fits on one page. A spreadsheet can carry a school further, since it holds more than one page and everyone already knows how to open one, but neither checks for a double booking or a hard-constraint violation automatically. That stays manual arithmetic.
What can dedicated timetabling software do that a spreadsheet can't?
It runs the hard constraints as rules a plan cannot violate and the soft constraints as preferences it optimises for, validates the setup before generating anything, and can name the reason when a solve turns out infeasible. It is also built to handle cases a simple grid or spreadsheet cannot represent, like a vocational workshop with a fixed number of stations or a placement block that sends students off-site part of the week.
Which method fits our timetabling process?
It depends on who does the building. If teachers build their own timetable in full, a template or simple spreadsheet is proportionate. If teachers draft and a planner consolidates, a shared spreadsheet starts to strain once a hard-constraint clash between two people's drafts only shows up at consolidation. If planners build the whole timetable themselves, dedicated software earns its keep the most, since one person now holds every constraint at once.