By Tim Mack · Updated May 2026 · 5 min read
How much prep a D&D one-shot needs depends entirely on the source. A published, ready-to-run one-shot needs zero prep — read it once and play. A homebrew one-shot usually needs 1–3 hours: roughly an hour to outline the arc and encounters, plus time to stat the key NPCs and pick a couple of maps. For a small group, you can run a complete session tonight with little or no prep if you start from a ready-made adventure.
I’ve prepped one-shots for six hours and run better ones with fifteen minutes of reading. The difference is almost never effort — it’s whether the structure was already done for you. Here’s how the numbers actually break down.
How much prep does a D&D one-shot need?
For a homebrew one-shot, budget 1–3 hours of prep for a 2–3 hour session. That covers a clear objective, three or four encounters, the handful of NPCs who matter, and a map or two. For a published one-shot built to run cold, the prep is a single read-through — fifteen to thirty minutes — and nothing more. The variable isn’t the table; it’s how much of the work someone already did.
What does “zero prep” actually mean?
Zero-prep doesn’t mean you walk in blind — it means the only preparation is reading the adventure once so you know the beats. A true zero-prep one-shot has the encounters balanced, the NPCs statted, the maps included, and the structure laid out, so there’s nothing left for you to build. That’s the entire design goal behind every adventure I publish, and it’s covered in depth in my no-prep one-shot guide.
How long does it take to prep a homebrew one-shot?
Plan on one to three hours, weighted toward the encounters. Most of the time goes to making sure fights are balanced for your group size and that the middle of the adventure has something to do. The story itself usually takes less time than people expect — a one-shot only needs one strong hook, one or two complications, and a clear ending. My guide on how to write a one-shot walks through that structure.
How do you prep a one-shot fast?
Cut scope before you cut corners. Pick one objective, cap yourself at three or four encounters, reuse stat blocks you already know, and skip anything optional. Prep the start and the climax in detail and leave the middle loose — you’ll improvise better than you’ll script. A visible deadline in the fiction does a lot of your pacing work for free, so you don’t have to prep transitions. For ready-made frameworks that collapse prep to almost nothing, my collection 101 Adventures for Busy DMs exists for exactly this problem.
Can you run a one-shot with no prep at all?
Yes — if you use a published one-shot designed to run cold. Pick one up, read the overview, and play the same night; the work is already done. That’s the whole appeal of the format for busy GMs, and it’s why a small group can game on a weeknight without anyone spending an afternoon prepping. See more low-prep adventure tips if you want the fastest possible path to the table.
Key Takeaways
- Published, run-cold one-shots need only a 15–30 minute read-through.
- Homebrew one-shots need roughly 1–3 hours, mostly on encounters.
- “Zero prep” means the building is done — not that you skip reading it.
- Prep fast by cutting scope: one objective, 3–4 encounters, a loose middle.
- A small group can game tonight with no prep using a ready-made adventure.
Frequently Asked Questions
How long should I spend prepping a one-shot? Fifteen to thirty minutes for a published one, one to three hours for homebrew.
Is it really possible to run D&D with no prep? Yes, with a ready-to-run published adventure. Homebrew always needs at least some setup.
What takes the most prep time? Balancing encounters for your group size. The story is usually the quick part.
Can a new DM run a one-shot with little prep? Absolutely — a published, zero-prep one-shot is one of the best ways for a first-time DM to start.
About the Author
Tim Mack writes small-group D&D 5e one-shots and guides at Anvil N Ink Publishing for 2–3 players and a single 2–3 hour session, and personally playtests every adventure before publishing. Browse the full library of small-group adventures for 2–3 players.