As the others have suggested, I would recommend the standard set of polyhedral dice; a d4, d6, d8, d10, d12, d20 and d% (although that last one isn't as often used).

I personally also add to this a second d20 (useful for when rolling with advantage or disadvantage) and 3 extra d6s (so that you have a total of 4d6 when rolling up new stats, if your DM uses that method for character creation).

The standard set of 7 polyhedral dice is the bare minimum. It should include dice with four, six, eight, twelve and twenty sides as well as two with ten sides (one will be numbered 1 to 10, the other 00 to 90).

Depending on what class you play you might want to get some extra dice for damage rolls. For example, if you play a wizard or sorcerer you might want to have extra six and eight sided dice for spells such as Fireball and Cone of Cold.

You could also just go on eBay and search for a pound of dice or assorted dice.

Need? None.

There are digital dice-rolling solutions which can handle this for you. Many apps and websites are available with different features. But you will have to ask your DM if it's okay to use, as it's easier to use dishonestly. Some DMs may or may not put some stipulations, such as using one with a roll history, or maybe they will ask you to only roll where they can see the screen.

There are mobile apps and web apps with varying features, one will surely suit your needs if you wish to not purchase dice or if you forget your dice. There are ones that just show numbers like above, there are ones that show like dice, there are ones that let you swipe/throw the dice, or shake your phone to roll. There are too many options for me to make recommendations, and I do not endorse any individual app.

Personally, I prefer rolling real dice, and if I forget to bring them, I'd rather borrow from the people at my table than use an app. For me it takes some of the "magic" away, whether it's me or my tablemates using the app. In a clutch situation, it's harder to get excited as everyone stands up and hovers over someone, eagerly awaiting the results of the roll, and then the player just tap a button on their phone and you see the number result.

But, it's a good option to explore if you're unable or unwilling to buy them.

Ideal Minimums

If you prefer to roll dice, the minimum you need is simply one set. As suggested in other answers, more is better to a point, they will speed up and simplify a lot of what you might want to do.

There are many calls to having tons of specific dice, but for example, a great axe-wielding barbarian really only needs 2d20s and 1d12 for optimum play. A greatsword barbarian just needs 2d20 and 2d6. About 5-10% of the time you will need to roll the weapon dice twice, but that's that. These dice would cover 99% of your requirements.

Most rogues can get by with 2d20, 1d4, and a few d6 for sneak attack. Other classes, 2d20 is barely a boon, just a nice-to-have. Monks are perfectly fine with 1 set as they rarely use two dice for any one attack, but the die they use changes as they level up.

If you are playing a spellcaster, then they do tend to need copious amounts of dice to play fluidly. If you're a warlock, 4d10 is a must. Wizards and sorcerers do ideally have a minimum of 4d6, but considering fireball uses 8d6 and there are spells utilizing 10+ dice, more is certainly not a bad thing. For spellcasters, I would recommend 3-4 of each: d4, d6, d8, d10. 1d12 and 1d20 is fine.

Any other class, 1 set is perfectly fine. Once in a while you will be rolling a die twice, but not enough to really impact the game.

I have a single set, including d4, d6, d8, d10, D12, d20, d% and d20. That is the standard for a 'set' and I have never wished for more dice.

That said, some people like multiple sets, and whenever one die rolls badly they switch to another one, so there is lots of room for preference, but 1 is good enough.

Minimally, each player will need a single d20, one die corresponding to their class's hit die size, and one die corresponding to their most commonly used attack. A barbarian with a greataxe can even get away with the d20 and a d12. (Occasionally borrowing a die from someone else for specific situations.)

Of course, usually, you'll have a more complicated character where you have different-sized weapons, abilities which use different dice, and so on. A single basic set of polyhedral dice will cover these, although you may find yourself rolling one of them several times in a row and adding.

When you have advantage or disadvantage, you roll d20 twice and pick the best — or worst. Using a single die and re-rolling is, of course, possible, but slows things down: not only does it take more time in sequence, you also have to remember what the first roll is, and if you just roll two dice at once you can quickly pick the right one. So, I suggest that you at least have two d20s.

If you have class features which require an additional die, and you don't have an additional die, re-rolling a single one and keeping a running total also slows things down. For example, rogues frequently add a d6 to damage — and multiple d6s at higher levels. You should have dice on hand for any frequently-used features like this. But this really varies by class selection and even particular path chosen, so there's no general rule.

When I've run games for middle-school kids generally with no previous D&D experience, I have actually given each kid a set of dice pre-matched to their pre-generated character. Two d20s for everyone, and other dice for their main attacks and signature features.

If you're a spellcaster, at higher levels, you'll probably want a wide selection of dice, because spells often require a handful of them. For example, good old fireball does 6d6, and cone of cold is 8d8. If you do that a lot, rolling eight times and adding as you go will get tedious for everyone. You don't necessarily need all eight, though: rolling 4d6 or 4d8 twice will do.

If your group is using the "4d6, drop lowest" method for ability score generation, you'll definitely want to have four d6s available, but since character generation is usually an infrequent activity (and rolling for ability scores only a small part of it), you can get away with just having 4d6 for the table, which will be easy if each player has a basic set of dice.

Also, just because you have a bunch of dice in your stash doesn't necessarily mean you'll want them in front of you. For example, although that d12 may be all the simple barbarian character needs, it happens that other classes almost never touch a d12, and having that die sitting on the table as an option to pick through can just slow things down (especially when you accidentally grab it instead of a d20 — something I see new players do a lot).

(Bonus tip, found in the DMG but which in my experience new DMs don't usually know about or encourage as much as I'd like:

Players are accustomed to rolling an attack roll first and then a damage roll. If players make attack rolls and damage rolls at the same time, the action moves a little faster around the table.

If you miss, just ignore the damage die, and if you hit, it's already rolled.)

Extra bonus! I said "minimally" in the first sentence, but if you want to go even more minimal you can use a house rule approach so each player only has a one d20 (or two d20s for advantage and disadvantage) but needs no other dice.

To do this, simply use point buy for character generation (or some similar method), and use fixed values for non-d20 rolls. For damage, take the average for the die size on a regular hit, or max damage for a crit. So, if the damage is 1d8, use 5 (or 4 if you prefer rounding down), or 4 (or 3) for 1d6. (You can experiment with other ideas too, like using minimum value when the hit exactly equals the target AC.) Other rolls (like using hit dice for healing) follow this same approach.

I haven't done this in 5E, but our group experimented with it in 3.5, and it works surprisingly well. It's a slightly different feel but also moves faster. In general, reducing randomness favors the PCs over the long term but it wasn't particularly overpowering, and it turns out the randomness from the d20 rolls really feels like plenty of influence from fate. On the downside, it's sometimes just plain fun to roll a bunch of dice and that's definitely missing.

And as a final post-script: I haven't suggested the "none" answer of using a phone app or some other digital approach, partly because I don't find that particularly fun myself, but mostly because it doesn't really change the answer: you still need an app which acts like the above.

Expanding on soxroxr's answer (which covers what dice you need for each class if you want to get physical sets)

You can use a digital roller to have infinite dice sets

There are apps and online dice rollers if you don't want to spend any money. Talk to your DM if they are ok with that beforehand. If they have any reservations, opt for a dice roller with a roll history like the one from WotC so the DM can look at the roll history as an 'audit' that you aren't just spamming roll until you get what you need. Or agree that all 'official' rolls on an app are the ones done where you immediately show the DM the result.

If you like the feel of rolling dice, some dice apps use your phones motion sensors so you can 'roll' your phone (don't actually roll it) to (partially) recapture the feel of rolling actual dice.

Pros of digitial:

• Free infinite dice


• Never lose a die


• Never knock over figurines


• Always legible


• If you are ADHD (figgity), no distracting dice to play with.

Cons of digitial:

• Not strictly random (but it's random in a way that it is indistinguishable from real dice and you can't fudge the results with a 'controlled' roll)


• No physical dice to actually roll / throw at people (in a silly way! Don't assault people!)


• If you are ADHD, no dice to fidget with.

Physical or digital largely boils down to personal preference. (And you need a DM who is ok with it, but I've never had a DM actually say no) I used the WotC die roller when I forget my dice and back before I had my own sets. To be honest, aside from aesthetics, there isn't really a difference play wise. There is a die equivalent for every 'cheat' the digital roller could enable (like rerolling during a lull in play and saying the last good roll was your 'official' roll); so using a roller with a roll history actually makes it easier to prove you aren't fudging the numbers.

I also have had no problem borrowing dice from friends, or using the dice of other people at the table (with their permission). This options only slows the game a bit since you both can't roll the same die at the same time (unless that player has 100+ dice =P).

As other answers have said, you don't strictly need more sets than are necessary for your own use. However it can be a good idea to have more, so that you can handle multiple rolls simultaneously. It's especially useful if you start to DM.

One detail with buying multiple dice which hasn't been covered in the other answers. If you do buy multiple dice, try to make sure you buy different colours. That way it's easy to do simultaneous rolls for events which affect several people, like "The acid splashes Joe and Fred. Joe's the red and Fred's purple. Here we go..." Or if you're dual-wielding, you could roll for your off-hand weapon attack at the same time.

If you buy a bulk set, you tend to get dice which are all the same colour unless it specifically says they're a mix of colours. That removes much of the benefit of having multiple dice. It can still be useful for formation-based combat rules like Warhammer Fantasy Battle, where one entire unit attacks another entire unit, but it's much less useful for RPGs like D&D or skirmish-based combat rules like Warhammer 40,000.

It also looks more fun to have lots of colours. :)

Use a mixed-quantities, colored set

I don't use a set with one of each die, but a set that contains multiple instances of each die. Each die type is colored in a unique way, making it easy to recognize them. For instance, the set I'm using is Dice of Rolling^[1], and it contains 5 purple d4, 10 red d6, 5 black d8, 5 green d10, 2 white d12, 2 blue d20 and 2 yellow d100. As they say "with this set you get all the quantities you need for gameplay with the 5^th edition".

The fact that all the dice are colored in a similar way given their number of faces greatly improves the speed at the table. My players fetch their dice based on the color and not on the number of faces, and find that it's easier and faster for them, I find it too. We never hear "Hey has anyone seen my d4?" or "Oops, I rolled a d8 instead of a d10, they're all the same color". This allows for a faster pace in the game and less extraneous pause that force everybody to return to their focus.

Also, the numbers of each die is rather well chosen for a full group. Having those dice in such numbers makes it easy to have a standard "roll 4d4, the purple ones". My players don't even bother bringing their fancy dice anymore bar their own d20. Actually, after getting two of these sets of dice (I bought the first one and the group offered me the second one after seeing the benefits), everyone can pick their damage dice at the start of the session for the whole game. The only dice passing hands are two easily recognizable d20. Being the DM, I get to keep a pair of d20 for myself and the players keep the other pair, without any trouble.

_{1: Not affiliated in any way, just a very happy customer.}

For buying purposes you could go with the set of 7 but this somewhat is inaccurate and really you could go with 6:

D10, D4, D8, D6, D20, D12

The Percentage Die and the D10 die are the same.

That said I would suggest getting in addition to those 6 or 7 to get at least 1 more D20 for advantage/disadvantage, and then slowly build up more dies for all the other stuff as well as singles.

Color Spray for example at level 1 requires 6d10 and goes up by 2d10 every additional level you cast it at. If you can at least roll 2d10 at a time you're cutting the time requirement for the spell by a lot which helps the flow of the game. Its the same reason you see more experienced players roll the attack damage and hit die at the same time instead of rolling, waiting to see if it hits, and then rolling for damage. Time at the table is precious and should be respected.

--

Personally I bought two of the sets of 7 in colors I like so I know which die are mine. Then most game shops, if you're playing at an actual store, will have a loosey bin where you can buy individual dice for about $0.20 each. So then I started buying looseys depending on specific spells or abilities I was using to save time -- and to support the local game shop.

Bare Minimum:

• 1d20


• 1d12


• 2d10 (Percentile dice, technically you can get away with 1d10)


• 1d8


• 1d6


• 1d4

My Recommended set as a player to reasonably minimize "multi-rolls" and help speed up gameplay.

• 3x d20 (5d20 if playing a fighter, all different colors) - Multi attack or multiple saves.


• 3x d12 (Weapon damage rolls mostly)


• 5x-10x d10's (Spells)


• 4x d8 (Cleric Spell damage / weapon damage)


• 10x d6's (Spells + sneak attack)


• 5x d4 (Magic Missile)

None

Further expanding Tezra's answer,

I haven't been touching dice for the last 2 years. I didn't touch it as a player and I didn't touch it as a DM other than using them as miniatures. dice rolling software will allow you to remain sane while playing complicated characters and leave you free to focus on other aspects of your character.

Simple well rounded options

roll20: Even if you don't use it as a party, roll20 will let you create macros for your character's actions and quickly roll complicated dice.

On mobile, I just found this app that lets you save macros which seems sufficient for most use cases.

Avoid 3D dice rollers. They mostly keep things equally complicated while also draining your battery if you are using a mobile phone. Some allow having a semblance of macros by letting you to have different tables with different dice on them but from my experience, they are not worth it.

A basic dice roller like the one from WOTC will also be somewhat useful but I find having the ability to save macros in one form or another very crucial as that lifts the maths load in it's entirety. It also means you spend less time interacting with the app you use and more time with the game

What I do

My own pipeline is somewhat specific to my use cases as I write my own software. First, I use this mobile app (not my work) to create my character. I have purchased the full version of this app which lets me automatically level up but free version still works with my pipeline. I then upload the character, created using this app to my own web application where most things about the character can be automated.

When I see something that isn't supported I can usually make sure it is supported before the next game session so I can make sure I have everything I need in electronic form. Currently, most things should be supported. The weaknesses I know about are lack of great weapon fighting support (though you can write your own dice formulas in the "Roll Dice" section to roll correctly for that) and that the spells page tends to elongate into infinity if you are a spell casting class. I will probably fix those once someone complains or I play a great weapon fighting, spellcasting class.

When I DMed in the past or when I was a wizard with animate objects, I used command line to roll the dice for multiple monsters. Now that functionality is available through this app that can quickly roll for damage by multiple monsters on a single target.