What Is RNG?

RNG stands for Random Number Generator — the system games use to introduce unpredictability. Every time a card is shuffled, a die is rolled, or a loot box is opened, an RNG is at work behind the scenes. Understanding how randomness functions in games doesn't just satisfy curiosity — it fundamentally changes how you approach strategy.

True Randomness vs. Pseudo-Randomness

Virtually no digital game uses truly random numbers. Instead, they use pseudo-random number generators (PRNGs) — mathematical algorithms that produce sequences of numbers that appear random but are actually determined by a starting value called a "seed."

This matters because:

  • The same seed always produces the same sequence — used in speedrunning to create predictable "random" outcomes.
  • PRNGs can be manipulated in some older games through specific actions at precise timing.
  • Game designers can tune pseudo-randomness to feel fairer than true randomness.

Types of Randomness in Games

Input Randomness

Randomness that occurs before you make decisions. Examples include drawing cards at the start of a turn or rolling dice to determine available resources. Input randomness is generally considered fairer because you get to react and adapt to whatever the game gives you.

Output Randomness

Randomness that occurs after you've already made a decision. A classic example: you attack an enemy with a 70% hit chance and miss. You made the right call, but the outcome punished you anyway. Output randomness can feel deeply frustrating because it disconnects decisions from results.

Variance Reduction Techniques

Skilled game designers often use techniques to make randomness feel fairer without eliminating it:

  • Pity systems: Guarantee a rare drop after a certain number of failures (common in gacha and looter-shooters).
  • Bag randomization: Instead of pure random draws, shuffle a "bag" of outcomes so each result appears roughly evenly over time (used in Tetris for piece distribution).
  • Dice fixing: Some board games let players reroll dice or choose among multiple dice results to reduce swingy outcomes.

How to Play Better Against RNG

Knowing how RNG works helps you make smarter decisions:

  1. Maximize expected value, not results. A 70% hit chance is still the right move even when it misses. Judge your decisions by their logic, not their outcome.
  2. Build resilience into your strategy. Don't construct plans that only work if luck goes your way. Layer your strategy so it succeeds across a range of outcomes.
  3. Understand variance. High-variance strategies (big swings) are most valuable when you're behind. Low-variance strategies (consistent gains) are best when you're ahead.
  4. Track patterns where possible. In card games, knowing what's been played tells you what's left. That's not luck — that's information management.

Randomness Is a Feature, Not a Bug

Randomness keeps games replayable, creates memorable moments, and ensures that skill alone doesn't create completely predictable outcomes. The best games use randomness to create interesting decisions rather than arbitrary results. Once you understand the difference, you'll start reading randomness as part of the game's design language — and play accordingly.