MacroMind matchup data: real ranked games, not opinions
Jax vs Karthus
How often does Jax beat Karthus in Jungle?
Jax into Karthus in Jungle: 48% observed win rate across 190 ranked games.
Global ranked sample: games from every region and every rank pooled together, not one server's stats. Data runs through patch 26.12; curves updated 2026-08-07.
By 15 minutes the median game has Jax behind by 529 gold.
Jax at 15:00
- Gold: -529
- CS: -21
- XP: -907
Typical gap to Karthus, from 190 games that reached 15:00.
Does Jax counter Karthus?
No counter here: Jax sits at 48% over 190 games. The swing lives in the spots below, so play the side you know better and chase the row that moves the number the most in this lane, then hold that lead through the first back.
Beating Karthus: the Jax game plan
A gold lead at 10:00 puts Jax at 61% across 62 games. Flip the lead and Jax falls to 42% across 128.
| The spot | Win rate | Games |
|---|---|---|
| Ahead in gold at 10:00 | 61% | 62 |
| Behind in gold at 10:00 | 42% | 128 |
| First blood | 54% | 129 |
| +kills at 10:00 | 62% | 82 |
| 0 deaths at 10:00 | 54% | 43 |
Someone usually dies here around 6:16 in the median game, and level 6 lands near 7:20. Until your spike is online, respect the all-in.
Jax's Jungle build, with receipts
Into Karthus specifically, Jax finishes Trinity Force first most often: 55.3% over 47 games of this matchup.
The most-finished Jax core is Trinity Force, Sundered Sky, Zhonya's Hourglass: 58.9% across 2,303 games when all three got done. All matchups, patches 26.1-26.12.
Most games start Gustwalker Hatchling + Health Potion; the first finished item is usually Trinity Force (9,957 games).
Skill plan: Jax players max W first and take E at level 1.