How to Collect T-Shirt Sizes for 100 Employees in Slack

How do you collect t-shirt sizes for 100 employees in Slack? Not with a thread. The “drop your size below 🧵” message tops out around 60% response even after three reminders, and turning 80 scattered, inconsistent replies into a clean vendor order sheet is an evening of copy-paste you’ll resent. T-shirt sizes look like the most trivial data-collection task there is, which is exactly why teams under-invest in the method and then lose a week to it — it’s a small problem that scales badly the moment you have a real headcount and a hard order deadline.

Why the thread fails

Threads fail in three specific ways, and each one costs you. They have no structure — people reply “M” without specifying fit, cut, or whether they meant unisex or fitted, so you’re left guessing or asking again. They have no tracking — finding out who hasn’t answered means manually diffing the thread against your roster, by hand, every reminder round. And they have no persistence — next year you start from zero and run the whole campaign again. Emoji-react voting is worse, not better: it hard-caps your options to the number of reactions you set up and silently double-counts whoever taps two.

The pattern that works

1. Structured collection. A short form or, better, a bot prompt with exactly three fields: cut (unisex/fitted), size, and quantity. (Still on Google Forms for this kind of recurring people-ops data? See our Google Forms alternative for HR for why it breaks down here specifically.) Link a real size chart — “M” varies between brands more than people expect, and an unlinked size question guarantees a batch of returns. Keep it to three fields; every extra one costs responses.

2. DM the stragglers, by name. This is the highest-leverage step. Channel reminders mostly reach the people who already answered — they’re the ones still reading the channel. A personal “hey, need your size by Friday for the order” reaches the rest, because a named, direct ask is much harder to scroll past than a broadcast.

3. Order with a buffer. Roll responses into counts per cut and size, then add roughly 10% in your two most common sizes. New joiners between order and delivery, the inevitable sizing mistakes, and the person who “definitely said L” will all draw down that buffer — budget for them rather than being surprised.

4. Keep the data. Sizes barely change year to year. Store them once and next year’s collection becomes a one-tap “still a medium?” confirmation instead of a fresh campaign — the same collect-once principle that should govern every durable fact about a person.

The 100-person math

At 100 people, plan around realistic numbers rather than hope: expect roughly 70% response to a well-run structured ask in the first week, climbing to about 90% once you’ve sent named DMs to the holdouts, and a final 3–5 people you’ll simply decide for — order their best-guess size, rounded up, because chasing the last few past the deadline costs more than the spare shirts. Budget a full week for the cycle, with the vendor’s order deadline as a hard, non-negotiable backstop you build the schedule backward from.

The automated version

This is a whole category of task — recurring, structured, low-stakes-but-genuinely-annoying — that bots exist to absorb. TeamRally runs the entire loop in Slack: it prompts each person individually, tracks responses against the roster automatically, chases non-responders without you writing a single DM, and stores sizes in the Preference Vault so you never run the campaign a second time. The identical loop handles dietary preferences and any custom preference you define, which is the point — the method generalizes, and so should the tool.

Part of the HR event logistics guide.

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Collect sizes once, reuse forever. TeamRally automates preference collection in Slack and Basecamp — join the waitlist.