How long should it take to plan a lesson?

The honest answer to "how long should it take to plan a lesson" is that it varies more than most workload guidance admits. A trainee teacher genuinely seeing the content for the first time, with no shared resources, might spend two hours on a single lesson. The same teacher three years later, with a department scheme of work and a stack of reusable slides, will plan the same topic in fifteen minutes. Neither of those numbers is wrong. They reflect different starting points.

That said, there is a workable range. For most secondary teachers past the early-career phase, planning a single lesson tends to take somewhere between ten and thirty minutes, assuming you are not building everything from scratch. If you are routinely spending an hour or more per lesson, something specific is usually going on, and it is worth working out what. If you are spending under five minutes per lesson, you are probably either an absolute veteran teaching a topic you know inside out, or you are not really planning at all.

This article looks at the variables that drive planning time up and down, the realistic ranges for different career stages and contexts, and the practical moves that tend to compress planning without compromising what happens in the room. It is aimed at teachers who want to teach well without losing their evenings, and at heads of department thinking about how to support their teams.

Before quoting numbers, it is worth being clear about what makes planning time vary so much from teacher to teacher and lesson to lesson. There are roughly five factors that account for most of the difference.

Experience with the specific content. Teaching A-level mechanics for the fifth year running is faster than teaching it for the first time, by a wide margin. The difference is not just familiarity with the content; it is also knowing which examples land, which student misconceptions to expect, and what works for which class.

Quality of department resources. A well-built shared scheme of work, with mapped resources, exam-style questions, and worked examples, dramatically reduces per-lesson planning time. Teachers in departments without this often spend longer on the basics (finding a decent worked example, writing retrieval questions from scratch) than on the lesson-specific thinking that actually changes outcomes.

Class complexity. A class with significant SEND needs, a wide attainment range, or particular behaviour considerations tends to need more planning than a more homogeneous group. The thinking required to adapt the lesson for specific students is real work, not paperwork.

Lesson novelty. New units, new specifications, and lessons that introduce a tricky concept for the first time take longer than lessons that consolidate or practise. The first lesson on quadratic equations takes longer than the third.

The document expected. A planning template that takes two minutes to fill in is very different from one that takes thirty. Some of what teachers report as "planning time" is actually "completing the planning document", which is a different activity.

With those variables in mind, here is a rough sense of where planning time tends to land at different career stages. These are not targets and not benchmarks; they are descriptive ranges drawn from workload research and teacher self-reports. Your own number may sit outside these, and that is fine if there is a sensible reason.

When a teacher reports spending two hours on a single lesson, the time is rarely spent on the parts of planning that matter most for the lesson itself. The two-hour version of the same lesson is not noticeably better than the forty-minute version. So where is the extra time going?

Resource hunting. Trawling the TES, looking through old shared drives, downloading PowerPoints that almost-but-not-quite match the lesson. This is high-volume, low-decision activity. It feels productive and absorbs time without producing much that ends up in the lesson.

Reformatting and prettifying. Reworking somebody else's slides to match your colour scheme, redrawing a diagram, fiddling with fonts. The educational return on this diminishes quickly past a certain point, but the work is concrete and feels finishable, which makes it especially tempting on a Sunday evening.

Over-detailed documentation. Writing the lesson plan in full sentences for nobody to read, completing every section of an over-engineered template, producing a teaching script. The plan is not the lesson, and the more time you spend on the document, the less you spend on the actual planning.

Perfectionism. Rewriting the same paragraph three times. Searching for the ideal hook. Building two versions of the practice questions in case the first set is too easy. Most lessons do not need the perfect version of anything; they need a competent version delivered well.

Mission creep. Starting at planning one lesson, ending at redesigning the whole unit. Useful in the right context, but usually not what you sat down to do.

If your per-lesson planning time feels too high, the following moves tend to help. Not all of them will apply, but most teachers can pull at least one of these levers.

The argument so far has been about compressing planning, but it is worth being honest about when more time is genuinely justified. There are lessons that deserve a longer planning session, and treating every lesson as a 15-minute slot can backfire.

First lessons on tricky concepts. The first time students meet electrolysis, ratios in trigonometry, or the unseen poetry comparison, the lesson needs to be carefully sequenced. Misconceptions formed at this stage are expensive to unpick. Spend the time.

Assessment design. Designing an end-of-unit test, an extended writing task, or a practical assessment is closer to curriculum design than lesson planning, and it warrants a longer planning slot. The downstream effects on student learning are large.

Lessons after a poor previous attempt. If the same lesson last year did not work, the time to fix it is now. A 45-minute planning session that fixes the failed lesson saves several hours of remedial teaching down the line.

Lessons being observed or taught to a new class for the first time. Some additional thinking time is appropriate here, both for the observation framing and because you do not yet know the class well enough to make all the usual shortcuts.

Most teachers who have got planning time under control have settled into some version of the same rhythm. The specifics vary, but the structure is broadly consistent.

Sunday or Monday morning, plan the week's lessons in batches by class, not by day. Identify the two or three lessons that need real thinking and the rest that are essentially small variations on the scheme of work. Block planning time accordingly.

Mid-week, light-touch tweaks. After teaching a lesson, scribble two or three notes on what worked and what did not. These notes inform tomorrow's lesson and next year's planning. Five minutes per lesson is plenty.

Friday afternoon (or wherever your reflection slot lives), look ahead to next week. Check the resources are sorted, flag anything that needs more thought, and shut the laptop. Doing this on Friday rather than Sunday tends to protect weekends without skipping the planning.

The goal is not to minimise planning time. It is to spend the right amount on the right lessons, and to protect time for the thinking rather than the paperwork.