How to Read D100 Percentile Dice (don’t make this mistake)

Dice are so integral to the gameplay of Dungeons and Dragons that we might as well use the abbreviation D&D&D… D3?

We use these polyhedrons to decide the outcomes of a lot of the situations our adventurers find themselves in.

While not everything comes down to pure chance, one thing is for sure… D&D players love our shiny math rocks.

Today, we’re going to be discussing one of the less common dice in our collection, a d100. 

What is a d100?

There are actually two answers to this question. One version of a d100 is a dice with one hundred sides. The other option is known as percentile die, consisting of two d10s, one labeled with every single-digit number 0-9, the other labeled for the tens place, so 00-90.

How do you read percentile die?

So percentile dice, 2d10s, are the far more common set up we’ll see, for a number of reasons.

One dice tells us what the tens digit is, while the other tells us what the ones digit is. On a specified set of percentile dice, a roll of 70 and a roll of 3 would be a very straightforward 73.

Non-specified percentile dice don’t have clearly designated tens digit dice, so I’d recommend rolling two colors and deciding ahead of time which represents which.

Otherwise, you might end up in a situation where a 1 and a 9 might give you dramatically different results.

Another note on non-specified percentile dice is that a normal 10 is denoted with a 10, or maybe a fun symbol, but very rarely a 0 like you’ll see on percentile dice.

Whenever we use standard d10s as percentile dice, we treat 10s as we would 0s, and then go about finding our result. It can be very confusing, and honestly I just suggest picking up percentile dice for like fifty cents at your local gaming store.

There is one thing that often comes up when dealing with percentile die, and that is the occurrence of a 0 and a 00. 

What does 00 mean on a percentile dice?

A result of 00 in your tens place, almost always means that there is no number in the tens place. A result of 00 and 1 is simply 1. However, when you roll a 0 and a 00, we treat that roll as a 100. 

The logic for this is actually very simple. There is no result of 0 when we roll percentile dice. Personally, I think it would be a lot easier, and much more intuitive, if we treated the dice rolls as if we went from 0 to 99, but that’s not how it works. 

Here’s a small table of some common results and what they are, just in case reading the explanation isn’t helping you one bit. I totally get it, this was a concept that took me an uncomfortably long time to wrap my head around.

Percentile Dice Chart
Red and Blue D10 Dice

With the standard dice I used to show these results, red signifies the tens place, while blue signifies the ones place.

The dice app I used is simply called Dice, by 7pixels, and you can download it for your phone here.

What is a One Hundred sided Dice?

A dice with 100 sides is pretty overwhelming. Unsurprisingly, there are 100 different sides to these bad boys. They look less like dice and more like golf balls that fell through the math department of MIT. 

Realistically, that’s a pretty apt description. One hundred-sided dice are almost misappropriately named. Dice come in many shapes and sizes. I’ve even seen a set of novelty dice that have tentacles sticking out of their various sides. Still, one of the staple definitions of dice is that they can be used in fair gameplay.

Are 100 sided dice fair?

No. At least, not anywhere near as fair as the dice we regularly use in D&D. Just looking at one of these monstrosities will show you that not all faces are created equally. Most of them don’t even resemble shapes, but rather an assortment of confused blobs.

Looking at the highest die we commonly roll, the d20, we see 20 triangular sides of matching surface area. That should be the bare minimum for fair dice, but there’s actually a lot more math involved.

If you’re interested, check this two-part video from Numberphile here. It gets into a discussion about the transitive symmetries of dice, which I’ll let them explain in more detail. Basically, we want dice that have an equal chance of landing with any side face-up. 

While d100s are incredibly unfair, there is a drive in the community to improve them. Some have weights inside that offset the unfair sides of the die, others have weird edges that allow you to have same-shaped sides.

It’s quite the undertaking and brings me to the only point that really matters to me about these dice. They’re cool.

I can throw all the fairness off the game completely out the window to break out a really cool piece of art on rare occasions. Just like jumbo d20s and tentacle dice, d100s are here for our entertainment.

They shouldn’t be rolled to decide everything at a table, but I don’t think we ever really thought that was the point.

What do we use percentile dice for?

Percentile dice are used for two main things, rolling percentages and rolling on large random generation tables. Unless you’re a wild magic sorcerer, these rolls will be pretty rare for you, and that’s okay. It makes it more fun when your DM finally utters the words “roll me a percentile die.”

Some other systems, and I believe at times older versions of D&D itself, utilize percentage dice for skill checks. I can see the benefits, it gives you a very clear picture of how much effort you put in. And yes, I don’t believe anyone can ever really give “one hundred and ten percent.”

At most tables, rng is at its peak when you’ve got a huge table to do it on.Wild magic, trinkets, how much gold your Orc throws at people, or whatever you want really. It just comes down to giving you a lot more options than even a d20 provides. 

Below is the wild magic surge table for Wild Magic sorcerers. It paints a really good picture of how many options you can have, and the ability to give certain outcomes a weighted chance of being chosen. As a DM, if you want to give your players a better chance of ending up with positive results, you simply assign more numbers to those results.

Wild Magic Surge Table

d100Effectd100Effect
01-02Roll on this table at the start of each of your turns for the next minute, ignoring this result on subsequent rolls.51-52A spectral shield hovers near you for the next minute, granting you a +2 bonus to AC and immunity to Magic Missile.
03-04For the next minute, you can see any invisible creature if you have line of sight to it.53-54You are immune to being intoxicated by alcohol for the next 5d6 days.
05-06A modron chosen and controlled by the DM appears in an unoccupied space within 5 feet of you, then disappears a minute later.55-56Your hair falls out but grows back within 24 hours.
07-08You cast Fireball as a 3rd-level spell centered on yourself.57-58For the next minute, any flammable object you touch that isn’t being worn or carried by another creature bursts into flame.
09-10You cast Magic Missile as a 5th-level spell.59-60You regain your lowest-level expended spell slot.
11-12Roll a d10. Your height changes by a number of inches equal to the roll. If the roll is odd, you shrink. If the roll is even, you grow.61-62For the next minute, you must shout when you speak.
13-14You cast Confusion centered on yourself.63-64You cast Fog Cloud centered on yourself.
15-16For the next minute, you regain 5 hit points at the start of each of your turns.65-66Up to three creatures you choose within 30 feet of you take 4d10 lightning damage.
17-18You grow a long beard made of feathers that remains until you sneeze, at which point the feathers explode out from your face.67-68You are frightened by the nearest creature until the end of your next turn.
19-20You cast Grease centered on yourself.69-70Each creature within 30 feet of you becomes invisible for the next minute. The invisibility ends on a creature when it attacks or casts a spell.
21-22Creatures have disadvantage on saving throws against the next spell you cast in the next minute that involves a saving throw.71-72You gain resistance to all damage for the next minute.
23-24Your skin turns a vibrant shade of blue. A Remove Curse spell can end this effect.73-74A random creature within 60 feet of you becomes poisoned for 1d4 hours.
25-26An eye appears on your forehead for the next minute. During that time, you have advantage on Wisdom (Perception) checks that rely on sight.75-76You glow with bright light in a 30-foot radius for the next minute. Any creature that ends its turn within 5 feet of you is blinded until the end of its next turn.
27-28For the next minute, all your spells with a casting time of 1 action have a casting time of 1 bonus action.77-78You cast Polymorph on yourself. If you fail the saving throw, you turn into a sheep for the spell’s duration.
29-30You teleport up to 60 feet to an unoccupied space of your choice that you can see.79-80Illusory butterflies and flower petals flutter in the air within 10 feet of you for the next minute.
31-32You are transported to the Astral Plane until the end of your next turn, after which time you return to the space you previously occupied or the nearest unoccupied space if that space is occupied.81-82You can take one additional action immediately.
33-34Maximize the damage of the next damaging spell you cast within the next minute.83-84Each creature within 30 feet of you takes 1d10 necrotic damage. You regain hit points equal to the sum of the necrotic damage dealt.
35-36Roll a d10. Your age changes by a number of years equal to the roll. If the roll is odd, you get younger (minimum 1 year old). If the roll is even, you get older.85-86You cast Mirror Image.
37-381d6 flumphs controlled by the DM appear in unoccupied spaces within 60 feet of you and are frightened of you. They vanish after 1 minute.87-88You cast Fly on a random creature within 60 feet of you.
39-40You regain 2d10 hit points.89-90You become invisible for the next minute. During that time, other creatures can’t hear you. The invisibility ends if you attack or cast a spell.
41-42You turn into a potted plant until the start of your next turn. While a plant, you are incapacitated and have vulnerability to all damage. If you drop to 0 hit points, your pot breaks, and your form reverts.91-92If you die within the next minute, you immediately come back to life as if by the Reincarnate spell.
43-44For the next minute, you can teleport up to 20 feet as a bonus action on each of your turns.93-94Your size increases by one size category for the next minute.
45-46You cast Levitate on yourself.95-96You and all creatures within 30 feet of you gain vulnerability to piercing damage for the next minute.
47-48A unicorn controlled by the DM appears in a space within 5 feet of you, then disappears 1 minute later.97-98You are surrounded by faint, ethereal music for the next minute.
49-50You can’t speak for the next minute. Whenever you try, pink bubbles float out of your mouth.99-00You regain all expended sorcery points.