Most schools buy one licence per teacher. Almost none need that many, and the overspend is usually the largest avoidable line in an online school's software budget.
The rule
A licence is consumed by a meeting that is happening right now. So what you need is not the number of teachers on your staff list — it is the maximum number of lessons running at the same moment, anywhere in your timetable.
A school with twenty teachers whose busiest slot is Tuesday 4pm with six concurrent classes needs six licences. Not twenty. The other fourteen teachers are teaching at other times, using the same licences.
Counting it properly
Take your timetable and, for every slot in the week, count the lessons in it. Your requirement is the highest number you find, plus a small margin.
Two things people miss:
Overruns overlap. A lesson scheduled 16:00–16:50 that runs to 17:05 is still holding a licence when the 17:00 class starts. If your slots are back to back, add one or two rather than sizing exactly to the peak.
Non-lesson meetings count. Parents' evenings, staff meetings, one-to-one interventions and admissions calls all consume a licence while they run. Parents' evening in particular can be your true peak — twenty simultaneous ten-minute appointments dwarfs any teaching slot.
Flattening the peak is a purchasing decision
This is the part worth internalising: your licence bill is set by one slot in your week.
If Tuesday 4pm has nine concurrent classes and every other slot has four, you are paying for nine because of one hour. Moving two of those classes to a neighbouring slot can cut the requirement by a fifth, permanently.
So it is worth looking at the timetable specifically through this lens once a year. The scheduling constraint that produced the peak is often historical rather than real — a subject blocked together because it always has been, rather than because it must be.
What a licence has to include for a school
Beyond the count, the plan matters:
- Meeting length. Free tiers cap group meetings at around 40 minutes, which is shorter than most lessons. This alone usually forces a paid plan.
- Participant cap. Fine for a class; check it before an assembly or a whole-year event.
- Cloud recording, if you record lessons — and storage is usually a separate, growing cost. A school recording every lesson and keeping them forever will meet that bill in year two.
- API and webhook access, if attendance is generated automatically. This is the one to verify before committing, because the whole automatic register depends on the platform being able to tell your systems who joined.
Who the licence belongs to
Assign licences to the school, not to individuals. A licence attached to a teacher's personal account leaves when they do, taking the recurring meetings and their recordings with it — which is discovered at the worst possible moment, usually during someone's notice period.
Recurring class meetings should be owned centrally and hosted by whoever is teaching that lesson, including whoever is covering it at twenty minutes' notice.
The costs that are not the licence
Two line items surprise schools in year two, and both are worth modelling before you commit.
Recording storage grows and never shrinks. A school recording every lesson adds storage every week and removes none, unless retention is automatic. The licence is a flat cost; storage is a slope. Setting a retention window is a purchasing decision as much as a safeguarding one.
Extra capacity for a handful of days a year. Parents' evenings and assemblies produce a peak that dwarfs any teaching slot. Buying for that peak all year is expensive; topping up for a fortnight is not, provided your plan permits it. Check whether it does — some do not, and that turns two evenings into a year-long uplift.
A worked example
A supplementary school: 14 teachers, 32 classes a week, timetabled Saturday 09:00–15:00 and two weekday evenings. The busiest hour is Saturday 11:00 with seven concurrent classes. Parents' evening, twice a year, peaks at twelve.
They need eight for normal weeks — seven plus one for overruns — and top up temporarily around parents' evening rather than carrying twelve all year.
The instinct was fourteen. The bill is roughly half.
The rest of the platform setup — recurring meetings, join links, the safeguarding settings to fix before day one — is in running live lessons on Zoom for a whole school.
