Converting 5E to OSR

"My players are used to D&D 5th Edition but I'd like to try an Old School Renaissance-style game. Can I convert or modify 5E?"
I've seen this question asked a lot. The answer is... yes. Technically.
Alexandr Komarov

The Right Tool For the Right Job

You're used to driving a compact automatic 2 wheel drive car on your daily commute. It's light, fuel efficient, smooth, and nimble.

You'd like to try off-road bouldering.

You could modify your commuter car. You could, given time and money and enormous amounts of effort, convert it to 4 wheel drive, rebuild the suspension, etc. You might get a decent off-road car for your troubles, but chances are you won't. Unless you undertook this project for fun or passion, the end result won't be satisfying. If you did it to save time, money, or effort, you definitely chose the wrong method.

D&D 5th Edition

As I see it, 5E has two halves. The first half is a character generation minigame. Read and buy books, pick options, imagine a future, plan a path. Usually, GMs ask people to show up with pre-built characters, so you might have weeks or even months of gestating a character in your head, getting attached, imagining them into life.

The second half is a story generation game using D&D combat rules. The goal is to generate interesting stories that highlight the characters. Deaths should be important and meaningful and tragic. Characters gain significant power, allies, contacts, and otherworldly abilities automatically by leveling. They go from heroes to superheroes.

The status quo of the world is threatened. The world is an OK place. Maybe it's not perfect, but it's not actively awful. The job of the PCs is to keep the world on an even keel. Challengers to the status quo are the enemy; chaos, orcs, cultists, criminals, madmen, supervillain schemers, and the like. Threats go from local to apocalyptic. The ideal end goal seems to be to generate a story that's really exciting to tell. People draw a lot of art of their characters and groups and of their adventures.

The rules are designed by other people. There are FAQs and patches and revisions. Official content usually takes priority over homebrewed content.

5th Edition handles this type of game extremely well.
Dwarf Fortress

OSR Games

There are several great OSR Primers out there. I like Ben Milton, Steven Lumpkin, David Perry, Bryce Lynch, and Chris McDowall's Principia Apocrypha (secret V2 here).

OSR character generation isn't a minigame. In most OSR systems it's highly randomized. You don't "build" a character;  you let the dice decide and deal with the results. Sometimes the numbers are good. Sometimes they're not. It rarely matters. Rolling up a new character takes a few minutes at most, and you'll need to roll up several new characters. Death is frequent and rarely glamorous.

Old-school games are not designed to generate stories. Stories will emerge, but they won't be planned or pre-written. Success depends entirely on the skill of the players in making good choices, but failure is still interesting. The world is usually ruined or disorganized. The status quo is not always worth preserving.

There are no official rulings. Your guess is as good as anyone's, most of the time.

Actually Converting  5E

First, ask yourself why. What is the goal?

If you all wanted to run a detective story set in 1950s France, you wouldn't use 5E just because your players know it. It's not the right tool. You'd probably pick a system specifically designed to help you tell a detective story.

Are you worried about learning a new system? Don't worry. If you can run a 5E game you can run an OSR game. In many ways it's easier. If you have problems, there's a large and supportive community out there willing to assist. This thread should answer most initial questions. There's a Discord channel here and a G+ community here. Most blog authors are happy to answer questions in their comments.

I've written a free "learning dungeon" for new players. People seem to like it.

Are you worried about a complicated, fiddly, badly-written system full of obscure tables and misleading descriptions, written when RPGs were a slightly different type of wargame? Don't worry about that either. There are plenty of "new" old school games with all the modern conveniences, and the "old" ones aren't nearly the tomes you're imagining. Most people tend to run some sort of franken-system anyway.

Pop The Hood
If you still want to convert 5E to OSR, you'll need to get your hands dirty. This isn't a clean operation like changing a headlight bulb or replacing a filter. It's messy. You'll need cut, weld, and modify.

Major Changes
-adjust the general tone of the implied setting
-rewrite character generation to use a random method. Dan D has a decent system here. Minimal backstories, minimal "optimal" mechanical choices.
-the only way to gain XP is gold. No story milestones, no killing monsters. Just loot.
-no balanced encounters

Best of luck. There's a complete guide out there but it's 191 pages long. Seems excessive.

You may just want to try another game. Anything with "AD&D", "OD&D" or "B/X" should work as a starting point.

Andreas Rocha

The Ludicrous Mechanical Compatibility of OSR Games

As you make these changes and pull apart the system, you may start to appreciate how it was put together. Once you understand the general principles (discussed in Principia Apocrypha) you can do two amazing things:

1. Adapt all sorts of content to your games. A module, monster, or idea no longer needs the right "brand" to be used. Grab a 5th edition monster book, a strange zine, a map from a 3.5 module, and some random tables from an AD&D booklet and run a game. If you understand how to adapt things to your system of choice, anyone who makes content is now making content for you. Some content is easier to adapt of course, and your tolerance for conversion might vary from others.

2. Write new content for other people to use. Content for OSR games varies enormously. Everyone's an amateur in a way. Write the stuff you want to see in the world.


  1. There's a new, super secret preview version of Principia Apocrypha here https://drive.google.com/open?id=1HEYO4a3AwQEZ29pjaPKPyQCip8PwSeodAZtmtKfZ2X4
    I'd also really appreciate my name in front of it with Ben and Steven's. Thanks!

    1. Will do! Wasn't sure how to credit, but I'll add everyone on the title page.

    2. Thanks, yeah no problem. At some point I realized I added about as much text as I was cribbing, so figured I shouldn't give myself such subtle billing.

  2. I'm running a 5e game, which I've glued a lot of OSR content onto.

    XP is mostly from treasure (50 xp per HD of enemies murdered, but it doesn't add up to much unless there's a LOT of blood)

    PCs are tougher than OSR characters, but they sometimes die ignoble deaths. One long-running character recently died unexpectedly in a hole in the ground when he poked the wrong puddle and got eaten by an ooze. I think he was seventh level? And the entire party had just finished a months-long ship expedition off the edge of the map, partly because of his 'epic quest' he was trying to complete. And now they're stuck on the Isle of Dread, with half the reason they came missing.

    I use the Death and Dismemberment rules from hack and slash/ ten foot polemic, pretty much as-is. I recently wrote up a 'psychic damage' extension to it, since psychic attacks seem to be common in the game.

    Players are encouraged to have alternate characters ready to go. New characters start at level 5 (I know I know), so players frequently play with their alternates, so if their 'main' dies, they're not too far behind in level. It's fairly organic, they spend a lot of time on the same ship, so they switch back and forth, or double up for adventures on occasion.

    One of the player's alternate is Many Goblins. I uh... didn't really convert this to 5e. I'm just using 'em as-is from this blog. It works well enough for an alternate, but if they ever became a main character I might haveta tweak it.

  3. Still have 5e game running, it's been 100% OSR by my reckoning:

    1) LotFP encumberance, LotFP xp awards for monsters (I award for stuff survived, not killed), everyone uses cleric xp advancement table.

    2) Last Gasp rules for Magic users and clerics.

    3) Roll on death & dismemberment at 0hp. Instant death if damage exceeds hp 0-CON.

    4) Group initiative.

    5) Keep 1 HD and 2 HD monsters the same. Double HD of everything else. Double damage too, most of the time.

    6) Roll on DCC alternate careers instead of backgrounds.

    7) Slow heal variant from DMG

    8) no feats.

    1. Yup - Only a few changes bring you 50% to OSR... a lot of it is about the philosophy of adventure design, and that's not that system dependent.

    2. Oh and just roll stats in order and again, that's 50% of the old school game (ie you don't "choose" your class by putting the best stats where you want)

    3. At that point, what's left?
      Just joking. I'm still not entirely sold on 5E's progression system and builds matching with the OSR style, but given the other changes listed, it's probably a negligible issue.

    4. I do take your point Skerples. That said, my players were used to getting progressively better; just for levelling up...so I wanted to keep that element. Also, it's just fun... cobbling it all together. The big D&D logo, shiny-shiny, etc... got a bunch of people interested, who I think otherwise might not have been (hipsters, musicians, festival people---no prior gaming background).

      Also, yes Ancalagon 3d6 in order. I did allow the concession of re-rolling net negative stat arrays.

      Just for the record, I've been running LL with the same group and it's going very smoothly indeed.

  4. Re: 5) that's with conversions from OSR stuff.

  5. If you're going to link to my stuff give my blog a shout out too

    1. Wait, the link was to the PDF directly, not to the blog post. Fixed it!

  6. I find with 5e and using OSR adventures, it's not the big picture but the particulars that will trip you up. The ranger can trivialize any wilderness exploration for the party by level 5. If you nerf the rangers ability without anything else though, you're nerfing one of the weakest classes in the game. Lesser restoration means disease becomes an easy to handle threat at level 3 rather than at level 5. Diseases in general are much weaker. Short rests radically alter the way attrition works and the time limits on things like torches, spells, resting, etc. aren't designed with ease of use for strict time keeping like you would in OSR games. As well, the movement rates, time to do an action, etc. aren't designed to neatly interact with resources for a time management minigame that's central to OSR dungeon crawling.
    I'm a big fan of 5e and it does its heroic fantasy gaming well but just focusing on the big things is going to simply make a more high lethality and treasure hunter focused version of 5e rather than a real OSR game.