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Percentile (Zocchihedron / 2xD10) • 100 Faces

D100 Roller

A D100 is a percentile die producing uniform numbers from 1 to 100. Each outcome represents an exact 1.00% probability.

Dice Tray
1d100
Click button or press Space to roll
Total Result
-- Ready
Roll Breakdown
Roll the dice to see outcome
Select Die Type Standard Polyhedral Set
Roll Configuration Quantity & Modifiers
1 – 100
2 – 1000
± bonus
âš™ Advanced Expression (NdM±K) â–¼
Shortcuts:
âš¡ Quick Dice Rolls 1-Click instant roll

Saved Presets

Roll History

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Exact Mathematical Probability

Combinatorial Engine

Calculates discrete binomial distributions, probability density, and cumulative odds for the active dice expression.

Range (Min - Max) --
Theoretical Average --
Most Likely (Mode) --
Total Permutations --
Query Target Probability
Exactly ( = X ) --%
At Least ( ≥ X ) --%
At Most ( ≤ X ) --%
Probability Density Distribution Hover / tap bar to view odds
View Full Probability Table & Combinations â–¼
Total Ways Exact % ≥ At Least ≤ At Most

Roll N Times (Multi-Trial Simulation)

Execute up to 10,000 repeated trials to calculate empirical distributions and statistics.

Trials --
Mean (Avg) --
Median --
Mode --
Min --
Max --
Sum --

Empirical Frequency Table

Roll Total Hits (Count) Frequency Bar Percentage
Click "Run Trials" to simulate rolls and generate frequency data.

About the D100 (Percentile (Zocchihedron / 2xD10))

The D100 is commonly known as percentile dice (d%). Because spherical 100-sided physical dice (Zocchihedrons) roll forever and can be hard to read, gamers almost exclusively roll two 10-sided dice: one for the tens column (00–90) and one for the single units (0–9).

Geometric Properties

Physical standalone D100s are based on 100-facet spherical polyhedra (Zocchihedron). In digital and standard tabletop practice, it represents the exact uniform Cartesian product of decimal tens and units.

Common Tabletop & Gaming Uses

  • • Call of Cthulhu and Delta Green percentile skill checks (roll under skill rating)
  • • Wild Magic Surge random tables in fantasy RPGs
  • • Loot drop tables, random encounter charts, and critical fumble tables
  • • Determining exact percentile probabilities and simulations

D100 Probability Basics

Every single integer from 1 to 100 has a flat 1.00% probability.

Minimum Roll 1
Maximum Roll 100
Theoretical Average 50.5
Odds Per Face 1 in 100 (1.00%)
Face Value Theoretical Odds Exact Percentage
1 1/100 1.00%
25 1/100 1.00%
50 1/100 1.00%
75 1/100 1.00%
100 1/100 1.00%

Frequently Asked Questions About D100

What is the average roll of a D100?
The mathematical expected average of a 1–100 die is (1 + 100) / 2 = 50.5.
How do two D10s make a D100?
One die marked 00, 10, 20... 90 serves as the tens digit, and a standard 0–9 die serves as the ones digit. A roll of 70 and 4 is 74. A roll of 00 and 0 equals 100.