Slido Free vs Mentimeter Free: Participant Caps, Export, and What Breaks First

The short answer: two free plans measured on different axes

Both Slido and Mentimeter give away a real, usable free tier — not a time-limited trial. The reason a straight "which is better" never settles cleanly is that the two plans are generous and stingy in mirror-image places. Slido is unlimited where Mentimeter meters, and Mentimeter is unlimited where Slido meters. So the right answer depends entirely on the shape of your event, not on which tool is "better".

The single most important difference is how each one counts participants. Slido's free Basic plan allows up to 100 participants per event, while Mentimeter's free plan allows 50 participants per month, counted cumulatively across every session on your account (GetApp, Mentimeter Help Center). Read those two sentences twice: one is a per-event ceiling, the other is a monthly, account-wide pool. They are not comparable on the same number line, and that is exactly why the choice flips depending on your cadence.

Participant caps: 100 per event vs 50 per month

For a single larger session, Slido's free plan simply stretches further: 100 participants in one event versus Mentimeter's 50. But Slido's cap is per *event*, and reusing the same "slido" across two sittings adds up — Slido's own community notes that two 75-person runs of the same slido count as 150 and trip the limit (Slido Community). The overage is not a hard wall: hosts get warned, and a session can be blocked only if you go significantly over.

Mentimeter's 50 is the opposite shape. It is a monthly pool that refills on the day of the month you signed up (not the 1st), and it is shared across *all* your presentations — two 30-person workshops in the same month already exhaust it. There is one escape hatch: Mentimeter never kicks live participants out and gives roughly an 8-hour grace period to finish a session, so a single presentation can run past 50 once — but you cannot start another live session until the counter resets. For more on how that grace period really works, see our breakdown of the Mentimeter free plan limits.

Polls, quizzes and question types: where each one meters you

Past the participant line, the two plans swap roles. Mentimeter Free is generous on content: unlimited presentations, unlimited question and content slides (up to 200 per presentation as a performance ceiling), and almost every question type — only the Quick Form slide is reserved for Pro. If you want to build a long, varied deck of polls, scales, rankings and word clouds, Mentimeter lets you.

Slido Free is the reverse. Its standout is unlimited Audience Q&A — participants submit and upvote questions with no cap, which is genuinely the best free Q&A on the market. But it rations the other interaction types hard: 3 polls per event and 1 quiz per event (GetApp). For a Q&A-led town hall that is fine; for a workshop that runs eight quick polls, you will hit the wall by the mid-point. It also includes event analytics, passcode protection and 30+ present-mode themes on the free tier.

• Choose Slido Free if your event is mostly live questions with a few polls — unlimited Q&A is the gift here
• Choose Mentimeter Free if you need many and varied interactive slides in one session — polls, word clouds, scales and rankings without a per-event cap
• Choose neither if your audience is over 100, or you need to keep the results — read on for why

Export, saved results and the vendor badge

This is where the two free plans agree, and where most comparison tables go quiet. Neither free plan lets you export your results. On Slido, a slido created under the free Basic licence cannot export data — even if you personally hold a paid account as a guest (Slido Community). On Mentimeter's free plan you cannot export to Excel, and worse, results are *not saved after the session ends* — institutional guidance is blunt: screenshot during the session or lose the data (UAL Digital Learning Support).

If a post-event report is a deliverable — a summary of what the room actually said, handed to a client or a leadership team — both free plans fail you on the same point. Export (CSV/Excel) only unlocks on a paid plan for either tool, which is quietly the most common reason people upgrade, more than the participant cap itself.

Both free tiers also keep a vendor badge on screen — "Powered by Slido" and "Powered by Mentimeter" respectively. For an internal retro nobody minds; for a client workshop or a branded conference stage, it reads as unfinished, and removing it is a paid feature on both.

Moderation of anonymous posts: neither free tier holds the line

When you collect anonymous input in front of a live room — a word cloud or an open-text question on the big screen — one abusive or off-topic submission is visible to everyone the instant it lands. The natural defence is *pre-moderation*: hold each entry and approve it before it shows. On both tools, that is a paid feature. Slido puts question moderation on its Professional plan and up; Mentimeter does not make it a free-tier focus either, and its profanity filter is a fixed word-list that its own help centre admits cannot keep up with new abusive terms, leaving the rest to manual deletion.

So on either free plan, your real-world options are: don't take anonymous open text, or station a person to watch the screen and delete fast. That is a staffing cost that never appears in a pricing table, and it is the single most underrated difference between a demo and a real event. If keeping the screen clean matters, price the moderation tier of whichever tool you pick — or a tool that moderates automatically, which the last section covers.

What upgrading costs — and why neither sells a cheap monthly plan

The free-vs-paid decision is really a free-vs-*annual* decision, because neither tool offers a true pay-as-you-go monthly plan. Mentimeter is billed per presenter, annually: the entry Basic tier is listed at $11.99 per presenter/month billed yearly (about $144/year) and Pro at $24.99, both excluding tax, on the official plans page as of October 2026 (Mentimeter Plans). Every seat is paid for twelve months whether it runs one event or fifty.

Slido has no monthly billing at all. Lifting the free caps means either an annual plan (its Engage plan lifts you to 200 participants with unlimited polls and exports, reported from around $150/year) or a one-time event plan — a single slido usable for up to 7 days, priced in tiers by audience size. That one-time option is the closest either incumbent comes to pay-per-use, but the per-event price climbs steeply with headcount, and it is still one event at a time.

What breaks first: deciding by how you actually run events

Forget "which tool is better" and ask "which limit do I hit first?" Three checks settle it without a spreadsheet.

That second check is where the whole free-vs-paid framing quietly fails. The occasional larger event — a couple of all-hands or workshops a year, each with 150–300 people — fits neither free plan (too big) nor an annual subscription (too idle). This is the gap a pay-per-use model fills: pay only for the days you actually run an event, with no cap and no idle months.

ZENIN CLOUD is built around exactly that. It is $70 for 7 days ($10/day), pay-per-use, with no contract, no cancellation step and no sales call — card checkout only. There is no plan-based participant cap (it handles hundreds to thousands of people on one live word cloud), everything collected exports as CSV on every use, and participants join by QR code only — no app, no login, no numeric code to read out. On the moderation point above, an AI classifier judges each post rather than matching a fixed word-list, so anonymous open text stays cleaner without someone babysitting the screen. For a single large event a year, that is a $70 charge instead of a full annual seat you would barely touch.

If your choice is still between the two incumbents, our deep dives on the Mentimeter free plan limits and the Slido free plan limits walk each cap in detail; if you only need one event covered, the single-event pricing comparison and the ZENIN pricing page lay out the pay-per-use maths.

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