Tag Archives: Disadvantage

Advantage to the Max!

As I discussed previously, Advantage is the powerful yet simple super-mechanic that sits within D&D5, providing an easily managed impetus to drive the game in whatever direction the DM wants to go: if not its beating heart, then certainly a clean well regulated kidney or perfectly functioning non-cirrohtic liver. No, I don’t think that metaphor works particularly well either, but feel free to take it and use it yourself all the same, no need to thank me.

The simplicity of Advantage, for some, may also be its weakness. For those gamers who like a little crunch from time to time, the Advantage mechanics are a bit of a one-trick pony. If things are good, you get Advantage. If things are bad, you get Disadvantage. If things are, well, complicated, you get nothing. Simple, yes, but not especially nuanced. However, another of the great things about Advantage is it is actually extremely resilient to being messed around with. Here are a couple of suggestions as to how you can take Advantage to the max.



If you want to reflect a situation where the cards really are stacked in one character’s favour, one easy house-rule is to throw in an extra d20:

Double Advantage: roll 3d20 and take the highest result.

I’d suggest this can add value in your game in some very specific circumstances:

  • Stacked Deck – a character has Advantage from 3 or more sources. E.g. they’re attacking with Help from a colleague against a Blind opponent who has been Stunned.
  • Did I crit? – The die roll could have some bearing on the situation that isn’t just success or failure. E.g. in combat, you might want to know if a blow is a critical hit or not.
  • Failure is an option – the odds aren’t so stacked in that character’s favour that you just automatically give them the most favourable result possible.

When not to use Double Advantage? If there’s no time pressure and no consequences for failure, don’t roll at all. Ever. Just don’t waste everyone’s time. Don’t turn our beautiful game into a dumb exercise in dice rolling.

Don’t show me the odds
Double Advantage has a relatively modest impact on the probabilities:

  • The odds of rolling <4 are pretty small in both Advantage & Disadvantage
  • Advantage gives you an 80% of rolling 10 or better. Double Advantage makes it 91%, the equivalent of another +2 modifier
  • Advantage will get 15 or more 51% of the time. With Double Advantage its 66%
  • Advantage has 9.8% chance of a natural 20. Double Advantage increases this to 14.3%

Advantage Prob 1 You can also check out the non-cumulative probabilities here: http://anydice.com/program/4704

Complicating what is simple
Of course, if you’re interested in taking a simple rule like Advantage and turning up the crunch level, there’s probably another Advantage rule that you’ve already discarded. That’s the rule that says any situation that has both Advantageous and Disadvantageous factors is resolved with a straight d20. It’s a rule with zero impact on any probabilities, it’s just there to keep things clean, simple and tidy. If you can handle a bit of untidiness in your game, just go for it. Not that you need my permission!



As I’ve said before, Advantage increases your chance of success, it doesn’t make success possible where it otherwise wouldn’t be. If that doesn’t sit right with you, you follow the D20 system Modifiers Golden Rule: dish out +2 or -2 as you see fit. Having said, that’s not really D&D5’s style. The Bless spell, with a hint of Cortex system, points to a better, more interesting way:

Boost: a character who has a Boost rolls an addition d4 and adds the result to their total. If you already have a bonus die from some other effect, e.g. Bless, roll this in addition to the boost die and take the highest.

You should apply Boost where something both makes an action easier for a character and makes it possible to exceed their normal limits. E.g. when one character uses the Help action by distracting their mutual opponent to create an opening, instead of awarding Advantage it may make sense to award a Boost. Similarly with the Working Together rules outside of combat: if the party ties a rope around the portly Wizard and gives him a bit of a tug to help him leap the crevice, they’re not just helping him achieve his maximum potential, they’re trying to push him beyond his limits. Award a Boost. Hell, maybe award an Advantage AND a Boost!

To see how this looks, see updated graph below. In terms of probabilities, outside of values <4 or >20, a single boost just increases the score by 2.5, the mean score for a d4, for any given probability. E.g. instead of 50% chance of getting 11, you have a 50% chance of getting 13.5.

Advantage Prob 2

As for Advantage plus Boost. Well, that’s the best option of all for near guaranteed success. And you know what, if you want keep stacking it on, you go for it. Even rolling 5d20, the 22% chance for a critical means there’s still plenty of uncertainty to help keep things interesting.



In summary, if you want to crunchify the Advantage rules, there are three immediately obvious options:

  • Allowing for super Advantages of 3d20 or even more
  • Scrapping the rule that says any number of Advantage + any number of Disadvantage cancel each other out
  • Replicating the die-based bonus from spells like Bless for more general modifiers such as team work bonuses.

Although they all add complexity, none of these will do any harm to the fundamental probabilities built into the system. So if you like crunch and you miss the stacking modifiers of 3rd edition D&D, you can easily replicate that style of play in D&D5 without breaking the game.

Caveat: there is one class that disproportionately gains from the Double Advantage house rule. With an increased critical range, the Champion sub-class of Fighter would benefit more than any other class from multiple Advantage. E.g. a crit range of 19-20 is 8% more likely with Double Advantage, compared to just 5% more likely for a natural 20. Game breaking? Probably not.


So what do you think, loyal, intelligent and charming reader? Is this something you’d consider adding to your game, or mere statistical frippery?

Please feel free to leave your comments below or send your thoughts, considered or otherwise, via Twitter @thedicemechanic

Edited 24th September: added Conclusion & Caveat. Corrected a typo, graph titles and ended probability curves for d20 rolls at 20.


Many Advantages of Advantage

One of the innovations in the new 5th edition of Dungeons & Dragons is the introduction of the Advantage / Disadvantage mechanic. In case you’ve somehow managed to miss it, instead of tracking lots of individual modifiers, a situation that is helpful to you gives you Advantage: roll 2d20 and take the best result. Similarly, when things are against you, you have Disadvantage: roll 2d20 and take the lowest value.

The benefit of the this mechanic in terms of simplicity – and I’ll just call it Advantage from now on, but everything I’m going to say applies in similar ways to Disadvantage – is pretty self evident. You don’t need to learn lots of individual modifiers, you don’t need to add and subtract lots of numbers on the fly: you have Advantage, or you don’t. Easy. However, it actually offers a range of other benefits that maybe aren’t quite so obvious, but that reveal just how damned clever Advantage is.

  • Keeping it tight – through Advantage, you improve the chance of success without increasing the range of success. The average result is higher, you are more likely to get a high number, but the maximum result is still 20. Why is this useful? It means DMs don’t have to account for the possibility of lots of modifiers when assigning a suitable difficulty number to a task. Even with the most positive circumstances, a DM can easily work out the maximum range for any given group of characters and set challenges at an appropriate level. It also means that whether a PC can accomplish a near impossible task is ultimately down to that character’s ability, not a pile of external bonuses. Advantage increases the chance of success, it doesn’t make success possible when otherwise it was not.
  • Preventing cock-ups – where Advantage has its biggest impact is in reducing the odds of getting a really low result. In this respect, it’s an excellent mechanic to represent operating under no pressure: you won’t always achieve amazing success, but you’re unlikely to absolutely muck it up. With Advantage, you only have a 25% chance of rolling under 11. To get the same odds using flat modifiers, you’d need a +5 bonus.
St George - Critical!

Critical Hit!

  • Vital blow! – giving flat modifiers can create the odd situation where you’re almost guaranteed to hit an enemy, but your chance of a critical hit is largely unaffected. This doesn’t make a lot of sense. If an opponent is easier to strike, it follows that it also ought to be easier to find that chink in their armour or land that especially telling blow. Advantage, on the other hand, increases both the chance of success and the chance of a Critical hit quite substantially (typically, from 5% to 9.8%). A victory for common sense and another reason for players to seek it out wherever possible!
  • Setting the tone – the final benefit I’m listing here is probably the most important. Most people I’ve spoken to assumed that the intent with Advantage is that it was the replacement for old situational modifiers such as flanking and the like. In fact, this isn’t explicitly the case. The D&D5 rules are actually rather ambiguous about when Advantage should be used. This makes it an extremely powerful tool for GMs to use in setting the tone of their game. You want a highly tactical 3rd edition style game? Award Advantage for getting into good positions, teamwork, attacking from elevation and so forth. You want a cinematic swashbuckling game? Award Advantage for over the top action, colourful description and bold derring do. You want a cautious slow-paced game? Award Advantage for taking care and planning ahead. You want reckless PCs charging at breakneck speed through your dungeons? Award Advantage for throwing caution to the wind, dynamism and energy.

In short, Advantage is probably the most powerful tool D&D has ever seen to reinforce whatever is important to you and make your game, your game.

Next up I’ll be looking a bit more at Advantage and how you might take it to the max.