How is Pokémon catch rate calculated?

Pokémon catch rate is calculated using the formula: a = ((3×MaxHP – 2×CurrentHP) × CatchRate × BallMultiplier × StatusModifier) / (3×MaxHP). A value ≥ 255 means guaranteed catch. The probability is then 1 – (1 – a/255)^3 in Generation III+ mechanics.

What Pokémon have the lowest catch rate?

Pokémon with the lowest catch rate of 3 include most legendary and mythical Pokémon such as Mewtwo, Rayquaza, Zekrom, Reshiram, and all box legendaries. At full HP with no status, even an Ultra Ball has only a ~0.4% catch rate against these.

Does sleep help catch rate?

Yes — sleep and freeze apply a ×2.5 status modifier to catch rate (Generation VI+). This is the strongest status condition for catching Pokémon. Paralysis, poison, and burn apply a ×1.5 modifier.

Catch Rate Calculator – Pokémon Catch Probability Calculator

⚪CATCHCALC

⚪ POKÉMON CATCH RATE CALCULATOR

Catch Rate
Calculator

Calculate the exact catch probability for any Pokémon. Input HP, status condition, and Poké Ball to see your odds.

▶ CATCH RATE CALCULATOR

SELECT POKÉ BALL

⚪Poké Ball×1

🔵Great Ball×1.5

🔴Ultra Ball×2

⚫Master Ball×∞

🏥Heal Ball×1

🌊Dive Ball×3.5

🌿Net Ball×3.5

🌙Dusk Ball×3.5

🏆Quick Ball×5(T1)

💛Timer Ball×4(T30)

Pokémon Catch Rate (0–255) Look up base catch rate in Pokédex (Mewtwo=3, Ratata=255)

Max HP Pokémon’s maximum HP at its current level

Current HP Lower = higher catch probability

Status Condition

Generation

Catch Probability per Throw

⚪

0a value

0%1-throw catch

0%5-throw catch

0%10-throw catch

HOW CATCH RATE WORKS

The Pokémon catch rate system is one of the most satisfying pieces of game mathematics in the series. Every throw of a Poké Ball runs a precise probability calculation using four variables: the Pokémon’s base catch rate, its current HP relative to maximum HP, the Poké Ball’s multiplier, and the status condition modifier. Understanding this formula lets you optimise every catching scenario for maximum efficiency.

As a competitive Pokémon player and data analyst who has studied the Gen III+ catch mechanics in detail, I’ll walk through the complete formula and how each variable affects your catch probability.

THE CATCH RATE FORMULA (GEN III+)

The standard catch rate calculation proceeds in two steps. First, calculate the a value: a = ((3 × MaxHP – 2 × CurrentHP) × CatchRate × BallMultiplier × StatusModifier) / (3 × MaxHP). If a ≥ 255, the catch is guaranteed. Otherwise, the per-throw catch probability is: P = (a / 255)^(1/4), which simplifies to approximately 1 – (1 – a/255)^3 for the three-shake check.

POKÉ BALL MULTIPLIERS REFERENCE

Ball	Multiplier	Best Used When
⚪ Poké Ball	×1	Common Pokémon, early game
🔵 Great Ball	×1.5	General mid-game catching
🔴 Ultra Ball	×2	Rare and legendary Pokémon
⚫ Master Ball	×255 (guaranteed)	Save for the rarest legendaries
🌊 Dive Ball	×3.5	Pokémon encountered while diving/surfing
🌿 Net Ball	×3.5	Bug-type and Water-type Pokémon
🌙 Dusk Ball	×3.5	Night-time or cave encounters
🏆 Quick Ball	×5 (turn 1 only)	First turn of battle — best opener
💛 Timer Ball	×4 (30+ turns)	Long legendary battles

💡 Pro Strategy: The optimal catch strategy for legendaries is: Quick Ball on turn 1 (×5 multiplier), then status condition (Sleep = ×2.5), chip to 1 HP, and switch to Timer Ball at 30+ turns (×4 multiplier). This maximises your probability at each stage of the battle.

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FREQUENTLY ASKED QUESTIONS

For legendaries, the optimal strategy uses: Quick Ball on turn 1 (×5), then Timer Ball after 30+ turns (×4), always with the Pokémon at 1 HP and asleep (×2.5 status). The Master Ball guarantees a catch but is usually limited to one per game — save it for roaming legendaries or your highest-priority target.

False Swipe (or Hold Back) is the safest way to reduce a Pokémon to exactly 1 HP without fainting it. At 1 HP, the HP component of the catch formula is maximised: (3×MaxHP – 2×1) / (3×MaxHP) ≈ 1.0, giving the full weight to the catch rate multiplier. This is the single most impactful variable you can control.

Pokémon with a base catch rate of 255 are guaranteed to be caught with any ball at any HP with no status condition. These include many common early-route Pokémon like Magikarp, Caterpie, Weedle, Pidgey, Rattata, Sentret, Wurmple, Bidoof, and most other route-1 encounter types.

This catch rate calculator uses the Generation III+ formula (Pokémon FireRed and later), which covers the vast majority of modern Pokémon games including DS, 3DS, Switch, and mobile titles. Generation I and II used a different formula — select “Gen I–II” in the Generation dropdown for the classic calculation.

Most legendary Pokémon have a base catch rate of 3 — the minimum possible. This includes Mewtwo, all three legendary birds (Articuno, Zapdos, Moltres), Rayquaza, Zekrom, Reshiram, and virtually all box art legendaries. Some sub-legendaries like the legendary beasts (Entei, Raikou, Suicune) have a catch rate of 3, while others like the Tapus have 70 and Cosmog has 45.