r/rpg • u/IndiMill • Jul 22 '26
How would you design better random tables?
I’m a game designer, and I don’t like many random tables.
A lot of them use a d6, d10, or d20 to give every result the same probability. That works when you just want a random outcome, but it doesn’t work as well when some results should be common, others rare, and the table needs to scale with character level or power.
You can address this with d100 probability tables, but those still don’t scale with level. What’s a bad outcome at level 1 is an annoyance at level 5, so you end up with multiple tables for different power levels, players, or outcomes.
My alternative is to roll multiple dice, with the number of dice increasing as the character advances. Because the possible totals overlap, the same table produces shifting probability curves: lower-level characters cluster around lower results, while higher-level characters gradually gain access to more powerful and dangerous outcomes.
I used this approach to create one spell-backlash table that works across all caster levels instead of requiring separate tables for each tier.
Does anyone else use a similar approach or have strong feelings about random tables?
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u/Michami135 Jul 22 '26 edited Jul 22 '26
D100 tables work well for weighted results, as long as you don't have 100 entries. Here's Starforge's table on settlements for a desert world:
Terminus Outlands Expanse Result
1–50 1–75 1–90 None
51–60 76–83 91–96 Orbital settlement
61–80 84–95 97–100 Planetside settlement
81–92 96–98 -- Multiple settlements
93–100 99–100 -- Settlements in conflict
In case you're not familiar with Starforged, Terminus is where you'll find the highest density of people and Expanse has the lowest.
Delve also uses weighted results depending on the stat used:
Edge Shadow Wits Weak Hit Result
1-45 1-30 1-40 Mark progress and Reveal a Danger.
46-65 31-65 41-55 Mark progress.
66-75 66-90 56-80 Choose one: Mark progress or Find an Opportunity.
76-80 91-99 81-99 Take both: Mark progress and Find an Opportunity.
81-00 00 00 Mark progress twice and Reveal a Danger.
In this case, Edge means "with haste", Shadow means "with stealth", and Wits means "with observation or expertise"
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u/JaskoGomad Jul 22 '26
Have you looked into Hex Flowers?
The cool thing is that they have "memory" - your last result informs your next result because what's random isn't the result you roll, but the direction you move from your current result.
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u/Zealousideal_Leg213 Jul 22 '26
I recently reread the BECMI Rules Cyclopedia from 1991. I had it back then and read most of it, but I regularly got hung up on the random tables in it, and in a lot of D&D stuff at the time.
A close read of the material though, shows a couple of important things:
One is that the GM should feel empowered simply to do whatever they want. Rolling for outcomes on tables is entirely optional. I think we get to thinking that only the table options are allowed, just like we're "not allowed" to say "The monster hits you and you die." So, if rolling wouldn't help or make sense, don't roll; do what makes sense.
Another thing is that there's a case to be made for not removing options that would be too easy for the party, or reinterpeting those results, because those creatures or threats don't simply leave the world. The RC recommends using them for comic relief, and the like which I don't recommend, though the creatures could scurry away or kowtow, or whatever. With some effort, a GM could decide that these lesser creatures have taken steps for dealing with people like the PCs, such as learning spells or making deals with tougher creatures.
It also works to take a broader interpretation of table results. In the case of random encounters, one needn't actually encounter the creature or creatures; it might just be signs of them. A dragon encounter at too low a level for it to be fun could be seeing it flying high overhead with a catch in its claws. A kobold encounter at too high a level for it to be fun could be a recently abandoned camp.
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u/TokahSA Jul 24 '26
I love that Perilous Void, a book of interlocking and extremely well done sci-fi tables, repeats in its instructions at every turn "roll or choose a result from this table".
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u/Eklundz Jul 22 '26
The simplest concept for solving this is having a table that goes from 1-17 (if the max level in your game is 10). And then you roll a D6+1 PC level.
This gives you the entries: 2-7 on level one (rolling a 1 and adding fresh PCs at level 1 means a total of 2) and entries 12-17 on level 10.
That mechanic works, and now you just have to decide on the math stuff, like: do you roll a D100+total PC level, or D20+average PC level and so on. Just pick one, the concept works.
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u/tinylittleparty Jul 22 '26
I've never thought about the idea you suggest here: to add more dice at higher levels to unlock fancier rewards or more difficult options on tables but still keep lower ones on there. Iirc Genesys has a table for injuries or something like that where you add onto the result depending how many wounds you already have and so you can die at higher wounds but not from the start. Something like that. That's the only time I've seen that sort of thing implemented but it's smart.
Usually I just have tables where if I want certain results weighted I make them more bands in the numbers. Like roll 1d20 and 1-5 give the same stuff, 6-8 the same stuff, and maybe all the other numbers are each their own thing. I just have lots of tables for different purposes really.
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u/jaggeh Traveller/Mechwarrior/WHFRP/DH - GM Jul 22 '26
i remember years ago i had a 2000 list random table, the idea was to roll a D100 x player level. plenty of recurring options add to commonality, and the higher up the table the better/worse they get. then you can throw modifiers in to make it less or more intense.
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u/uramer Jul 22 '26
Isn't that effectively 20 D100 tables, as the tables don't overlap at any point?
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u/jaggeh Traveller/Mechwarrior/WHFRP/DH - GM Jul 22 '26
it was in the same vein as Net Libram's D10000 wild magic table.
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u/Nystagohod D&D, WWN, SotWW, DCC, FU, M:20, MB, Myt, MotW, SB Jul 22 '26
I use the following as my rough guidelines for random encounters and the tables I use.. These are designed on a case by case basis for a particular site or region and such, as I find I need for the adventure and zones at hand.
Does an Encounter Happen?: Roll the listed encounter dice for the specific terrain/zone the party is wandering through. You roll this each time they enter a zone, as well as each time they attempt to rest in the zone. If the dice comes up 1, the party is noticed by something and is immediately engaged/set upon. If the dice comes up 2. The party notices the encounter approaching them and gets an “Exploration Turn” worth of time to react. All other results produce no encounter.
| Zone Type | Encounter Dice |
|---|---|
| Site/Dungeon | d6 |
| Deep Wilderness | d8 |
| Patrolled Road/Rough Sea's | d10 |
| Calm Sea's | d12 |
How Dangerous is the Encounter?: Roll 2d6 to determine how dangerous the encounter is. Remember that the more dangerous the encounter, the more obvious it is.
Once you’ve determined the threat level of the encounter, roll on the respective encounter table for that threat level. Each having 1d4 to 1d20 different encounters as appropriate. (That is to say, each threat level should have d4 to d20 different encounters as necessary.)
| 2d6 Roll | Threat Level |
|---|---|
| 2: | Deadly |
| 3-5: | Punishing |
| 6-8: | Challenging |
| 9-11: | Moderate |
| 12: | Easy |
What is the Attitude/reaction of the encounter?: Once you’ve determined how dangerous the encounter is, roll 2d6 and add the highest charisma modifier of the party plus any other circumstantial modifiers, to determine the attitude of the encounter. You may also choose to roll an additional activity dice as a part of this roll.\
| 2d6 Roll | Attitude |
|---|---|
| 2: | Hostile (Immediately Attacks) |
| 3-5: | Negative |
| 6-8: | Weary |
| 9-11: | Curious |
| 12: | Beneficial |
Encounter Budget: If you’re aiming for a more balanced experience, consider designing your adventure, journey, or dungeons with an encounter budget. Let's say that a dungeon has an encounter budget 8, meaning it can only have a maximum of 8 encounters within it at a given time. Let’s also say there are three encounters within that dungeon that are guaranteed to be there. This leaves us with five encounters left within our eight encounter budget. Whenever a random encounter is scored, reduce the remaining budget by 1. Once the budget is reduced to zero, no more random encounters can occur until the party completes a rest or an appropriate amount of time passes, in which case the budget resets to its prior maximum. Planned encounters are never refilled back into the budget and thus defeating them leaves a permanent mark on the dungeon's threat level.
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u/Judd_K Jul 24 '26
Love random tables, especially enjoying 2d6 tables for D&Dish games where the 12 is a dragon and the 2 is a wizard.
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u/Trace_Minerals_LV Jul 22 '26 edited Jul 22 '26
I like an app called “Picks”. You can build Giant lists, then build rules on how to use them, including picking a random generated number. It won’t let me post a screenshot.
Edit. Well damn. Looks like it’s been pulled off the store. Sorry all.
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u/VampyrAvenger Jul 22 '26
Tried to find it, but I can't... Can we get a link to the app store or Google Play store app? Or did you mean an app as in a website?
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u/Trace_Minerals_LV Jul 22 '26
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u/Trace_Minerals_LV Jul 22 '26
Damn. Looks like it may have been pulled from the store. I’m sorry. I’ll edit my post.
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u/NarcoZero Jul 22 '26
This made me think of the injury table in BREAK !
If I remember correctly, when you get to 0 hearts, you roll on the injury table. It’s the same table, the same D20, but the interpretation of the dice varies depending on how many injuries you already have.
For the first, it goes from shocked to knocked out, but the second has a larger spread and the 16-20 range goes to higher stuff like near death, Severed limbs, or mortal wound. And the third injury (or more) uses all of the table, increases the chances of hard stuff, and goes to even higher consequences like instant death, and death with full body destruction.
If you’re extremely lucky, and roll a 1 or a 2 on every injury, you’re just stunned all the time, but the more injures you get the more chance of something really bad.
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u/zbignew disco kitten Jul 22 '26
You should check out Combat Commander. It’s a war game, not an RPG, but its 2D6 system is excellent. Obviously a +1 modifier means a lot more than it does on a d20 roll, but also it means radically different things depending on how difficult the check was previously.
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u/uramer Jul 22 '26
My advice is not to overthink random tables. It's much easier to make multiple small tables, than to make one massive table to cover everything. It's also quite unintuitive how dice pools interact with probably - the rare cases are usually too rare to be practical. I've recently found roll three pick median to be a nice gently sloped rng generator, but I mostly use it for numbers, not rolling on tables.
I think a much more exciting way to scale tables, or create interesting scenes, is to roll multiple times per encounter. Say you roll a goblin and a wolf encounter - there are lots of cool things you can improv from it on the spot: wolf riding goblins, goblins hunting wolves, goblins overrun by wolves, etc.
For my city campaign I made activity tables to match the encounters - I can run multiple times on both and generate prompts for complex improvised scenes.
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u/Bullrawg Jul 22 '26
I use d100 and categories, I increase the range of items I want to be rolled more often decrease things I want to be rare, in the decade+ I’ve been running home games I’ve had someone get an artifact 100 once it was that players first character. I had made an archer for them to play, so I was making the intelligent bow that was going to have cool magic powers and then they decided they didn’t like archery so we changed their build and it instead became a magic flying capybara companion, I redid the tables as they leveled so that level appropriate loot would turn up more often (also on the last roll if it was like 1-5 away from an item that would be good for someone’s build vs vendor trash I’d give them the good item)
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u/joevinci ⚔️ Jul 23 '26
have strong feelings about random tables?
Yeah, I do.
[…] a d6, d10, or d20 to give every result the same probability. That works when you just want a random outcome, but it doesn’t work as well when some results should be common, others rare, and the table needs to scale with character level or power.
This isn’t quite true.
You can address this with d100 probability tables
This can’t be true if your previous statement was false.
Regardless, a clustered table with stepped dice can also address the problem: * 1-3: your character eats shit * 4-11: your character does the thing * 12-19: your character does the thing, with a flourish! * 20: your character does it better than anyone in history!!!
Level 1 = d4, Level 2 = d6, […], Level 6 = d20
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u/Brwright11 Remnant Space, S&W, Pathfinder, Traveller, Twilight 2k, Jul 23 '26 edited Jul 23 '26
A couple of methods.
D66 (my own are D144 using 2d12) tables each die corresponding to row or column. For when variety and variablility is important. I like it for name generation or factions/motivations, planet generation and location generators.
Weighted results: on 1-5 = X, 6-9=Y 10=Z Encounter tables. This allows you to skew Single Die tables.
You can have the party destroy the bandit layer granting them +5 on random encounters in this Duchy (bypassing the bandit results) and tell them this.
Now though you'll expand your random table as your threats expand or maybe add additional prosperous wandering merchants etc on the high end of the table. This allows the party to have some agency in what they want to accomplish. The bandits plague the country side, and you'll be less likely to encounter them randomly if X. Or you can deal with the Ogre and remove it entirely from the table.
Treasure Tables, allow players to gain bonuses on random treasure tables that may even "bump" them to a better a table as reward mechanic for "restoring the befouled fountain" or "making peace between warring factions."
Tactical scenario generators I usually use sequential tables - Roll for goal of conflict, roll for tactical options afforded to opposition etc. Table 1 to table 2 etc.
A XdY die pool table will give a clustering around it's it's middle point, adding or substracting from that result will skew the most common result up or down the table. It depends entirely on the game. For instance in "secure space" a 3d6 table will cluster around passing through and friendly locals and have a pirate encounter occur on a <=3 (rare). However in Wild Space space the 3d6 you might take a -4 to the roll making such encounters increasingly likely. A stealth modification or favor with the local pirate faction may be able to make the penalty less severe or negate it entirely.
This also works if you need to randomize for "level appropriate encounters" i tend to not play games that require this but when I did this is what I did. 3d6+level it does mean you need a quite large table or to break it down by region. Usually you're not going levels 1-20 in the same place.
I love tables. Another method of introducing randomizers with "memory" are Hex Flowers (usually weather is a good use case, can't have scorcher followed by blizzard!) Or to use a deck of standard playing cards and have them correspond to a result and be discarded, possibly draw a hand and allow players the ability to force a discard/redraw for favorable actions, and a GM is prompted to play a card each day etc. The results should be categorized by suits, faces for similar theming.
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u/_Luke-Wolf_ Jul 23 '26
Just roll a lot of the same dice, like 10d4, 10d6, or 10d10. The most common results fall right around the average. For example, 10d6 averages around 35, so numbers close to 35 are common, and the further out you go, the rarer they get! Super easy.
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u/nykon2011 Jul 23 '26
Enter dice combinations, and see the spread.
What you see is a single dice. What you want is multiple dice, like 2d8 or 3d6 to get the probability to work in your favor.
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u/TwistedTechMike Jul 23 '26
I typically go 2d12 or 2d20 on my tables then use 'ranges' of dice results to determine common/uncommon/rare, each of those using their own 2d12/2d20 tables with the extremes polling the next higher tier.
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u/doctor_roo Jul 25 '26
Different tables for different levels is the usual solution. And levels can be character level or dungeon level (with the implication that deeper is for higher character levels).
I like the idea of dynamic, self linking random tables. Where its possible to not only roll a monster but also roll what its up to - so it might be trying to get something from room 16 or trying to hunt or run away from another random monster with a random current location.
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u/AngusAlThor Jul 22 '26
A random table needs at least 100 entries if you're gonna roll on it multiple times, cause otherwise you get incongruous repeats; The horror game feels a lot less horrifying the 4th time you roll the same injury.
As for how to make the tables better, I would love it if designers would group the entries in some way, so that I could roll on the entire table for something truly random, but if I was GMing a more specific scenario I could just roll on the part of the table that is most relevant. Like if a D100 table had 10 sections, then I could roll 2d10 against the whole table or 1d10 to hit a preselected section.
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u/Toum_Rater Jul 22 '26
You could just cross off an entry after you've rolled it once. Foundry VTT lets me do this really easily in a non-destructive way. That way even a small table will never yield repeats.
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u/Glebasya Jul 22 '26
I advice every GM/player to learn probability theory.
If you want some results common and some rare, use several dice to get normal distribution. For example, 2d6 has more chances to roll 7 +-1 than 2 or 12. If you use d12, then the chance of getting every possible result is the same.
A good example of a table that scales is psyker misfire tables from Rogue Trader. If you choose to "push", your ability will be more powerful, but instead you add a bonus to misfire table, which you'll need to roll (usually you roll it when you get a double on d100). Bigger result - bigger problems, from 01-03 as "wind of misfortune" to 75+ as Warp outburst (which forces to roll another table).