Too much text on slides: the fix is the claim, not the font
A slide has too much text when it is written for the reader instead of the room: the full sentences belong in the handout, the reasons in the speaker notes, the second point on the next slide. The fix is not a smaller font; it is the claim as the title, three to five short lines under it, and the rest moved to where it will be read. The deck loses no content.
This guide explains where the text comes from, gives a rule for what a slide can carry, and walks through a pass that thins a forty-slide deck in an afternoon.
Where the text comes from
Instructors write dense slides for good reasons: the slides are also the handout, they are the notes, and a full sentence is defensible. All three are real needs. The problem is that a slide is the worst place to meet them: the room reads the slide instead of listening, the back row cannot read it at all, and the deck becomes a document projected at 20 pixels.
The answer is three artefacts from one source: the deck for the room, the handout for the reader, and the speaker notes for you. Once those exist, the slide can be sparse without losing anything.
A rule for one slide
- The title is the claim, a full sentence if needed ("Round-robin's waiting time depends on the quantum"), not a label ("Round-robin").
- Three to five lines under it, each a fragment of under ten words: the evidence, the example, the caveat.
- One figure, table or code block at most, sized to be read from the back.
- A source line at the bottom.
- Nothing the room is not meant to read now.
A slide that needs more is two slides. A slide that needs a paragraph is a handout page.
The ten-minute pass, per block
For each slide of a block:
- Find the claim. If the title is a label, rewrite it as the sentence the bullets prove. Often the slide's first bullet is the claim in disguise.
- Move the full sentences to the handout. Copy the paragraphs into the week's handout under the claim; replace them on the slide with fragments.
- Move the reasons to the notes. "Because…", "note that…", "this matters since…" become the speaker note, which you will say.
- Split at the second idea. A slide with two claims becomes two slides with one each. Slides are free.
- Cut the seventh bullet. The room will not read it; if it matters, it is the next slide.
- Check the figure. If the text was explaining the figure, the figure needs a caption and the text can go.
Forty slides take about an hour this way, and the deck usually grows to fifty thinner slides with the same content and a handout that did not exist before.
Before and after
Before:
Scheduling criteria. CPU utilisation should be maximised because idle CPU is wasted capacity; throughput, the number of processes completed per unit time, should be maximised; turnaround time, waiting time and response time should be minimised, although in practice these conflict and a scheduler must choose which to favour based on the workload.
After, slide:
No scheduler wins on every criterion
- utilisation and throughput: higher is better
- turnaround, waiting, response: lower is better
- they conflict; the policy picks a winner
Silberschatz et al., 2018, §5.2
The paragraph went to the handout under the same claim; "based on the workload" went to the note as the question to ask the room.
Text that belongs on the slide
Quotations you will read aloud, a definition the room must copy, a formula, the exact wording of an exam question. Those are text and should be large. The rule is not "fewer words" but "only the words the room reads now".
Tools
The font size guide explains why shrinking does not work; the slide count calculator shows how many slides the hour can take, which is usually more than the dense deck has. Lecture Studio's Tighten the slides starter in the unit chat does the pass above on a Marp deck: claim-as-title, fragments, moves the rest to notes, and shows the diff before writing.
FAQ
How much text should be on a lecture slide?
A claim as the title and three to five short lines under it, plus one figure or table and a source line. More than that is the next slide or the handout.
What do I do with the text I remove from slides?
Full sentences go to the handout under the same claim; reasons and asides go to the speaker notes; a second idea becomes its own slide.
Is a smaller font a fix for dense slides?
No. Below about 18 px the back row cannot read it, and the slide still competes with you for attention. Split, move or cut instead.
Should slides work as a handout on their own?
No; that is what makes them dense. Produce the handout from the same claim list and let the slides be sparse.