OSRS Inferno Simulator & Zuk Trainer

A free, browser-based OSRS Inferno simulator and TzKal-Zuk trainer. Practice any wave of the Inferno, learn mob spawn patterns, and rehearse the Zuk fight with accurate Old School RuneScape mechanics. Often referred to as "inferno sim", "inferno simulator", "zuk trainer", or "jad simulator".

Features

• Pick any Inferno wave and replay random or specific spawns.
• Practice the TzKal-Zuk boss fight, including the shield phase and healers.
• Simulate Jad and triple-Jad waves with accurate prayer-switch timing.
• Configure gear loadouts, prayers, and tile markers.
• Runs in the browser on desktop and mobile — no install required.
• Open source re-implementation of OSRS combat mechanics.

Frequently asked questions

What is the OSRS Inferno Simulator?

It is a free in-browser trainer for the Inferno in Old School RuneScape. You can practice waves, the shield phase, and the TzKal-Zuk fight without risking your character or supplies in-game.

Is the Inferno Sim / Zuk trainer free?

Yes. The inferno simulator and Zuk trainer are completely free and run entirely in your browser.

Does the Inferno simulator work on mobile?

Yes. The inferno simulator works on modern mobile browsers as well as desktop.

How accurate is the Zuk simulator?

The simulator is built on an open-source re-implementation of the OSRS engine, modeling tick timing, NPC behavior, prayers, and combat formulas as faithfully as possible. Bug reports for OSRS mechanics divergences are welcome.