The Ultimate OSRS Defence and Hit Chance Calculator

Ever wonder why you’re burning through supplies at Vorkath while others seem to last forever? Or maybe you’re debating if that expensive Justiciar armour is really worth the investment for your next slayer task. This tool is built to answer those exact questions.

This OSRS Defence and Damage Mitigation Calculator is designed for players who want to optimize their survivability. Whether you’re an Ironman planning a gear grind, a mid-level player prepping for your first boss, or a veteran min-maxing your setup, this calculator helps you understand exactly how your gear and stats protect you, allowing you to make smarter decisions and extend your trips.

Real-Life Example: Prepping for Vorkath

Let’s say you’re a mid-level player trying to improve your Vorkath runs. You want to know if upgrading from a Dragonfire Shield to a Dragonfire Ward is worth it against Vorkath’s Ranged attacks.

• Your Setup: 85 Defence, wearing Karil’s leathertop, using Protect from Missiles.
• Scenario A (Dragonfire Shield): Your Ranged Defence Bonus is +125. You input this into the calculator.
  • Output: Vorkath has a 14.2% chance to hit you with his Ranged attack.
• Scenario B (Dragonfire Ward): Your Ranged Defence Bonus is +145. You update this value.
  • Output: Vorkath’s hit chance drops to 12.8%.

This simple comparison shows a tangible defensive improvement, helping you decide if the cost is justified for longer, more consistent trips.

How to Use the Defence Calculator: Step-by-Step

Our calculator simplifies the complex OSRS combat formula into a few easy steps.

1. Enter Attacker’s Details: Start with your opponent. Select a common boss from our list or input the monster’s Attack Level and Attack Bonus if you know them.
2. Input Your Defensive Stats: Fill in your character’s information. This includes your Defence Level and any active prayers like Piety or Steel Skin.
3. Find Your Equipment Defence Bonus: This is the most important step. Open your “Worn Equipment” tab in-game and click the “View equipment stats” button. Find the specific defence bonus for the attack style you’re facing (e.g., “Defence – Ranged”) and enter that number into the calculator.
4. Analyze Your Results: The calculator instantly shows you the monster’s exact Hit Chance (%) against you. This tells you how often you can expect to take damage, giving you a clear measure of your survivability.

Is there a free OSRS DPS Calculator online

Key Features of the Calculator

• Instant Hit Chance Calculation: Stop guessing. Get the precise percentage chance a monster has of landing a successful hit on you.
• Side-by-Side Gear Comparison: Easily swap your equipment bonus values to see the real-world impact of upgrading a shield, a chestplate, or any other piece of gear.
• Focus on Survivability: Unlike DPS calculators that only focus on damage output, this tool is dedicated to your defence, helping you plan for longer trips and use fewer supplies.
• Simple Interface: No confusing spreadsheets or endless dropdowns. Just the essential inputs you need for a quick, accurate calculation. Perfect for using on a second monitor or your phone while you play.

Frequently Asked Questions (FAQ)

What’s the difference between my Defence Roll and Hit Chance?

Your Defence Roll is a hidden number calculated from your level and gear bonus. The calculator uses this roll to determine the final Hit Chance, which is the actual percentage probability that an enemy’s attack will be successful against you.

How much does my Defence level really matter?

Your Defence level is a major factor in your Defence Roll. Each level provides a significant boost to your base defence, making it more effective than gear bonuses at lower levels. It’s the foundation of your character’s ability to avoid damage.

Why doesn’t this calculator show my Max Hit?

This tool is specifically a defence and damage mitigation calculator, designed to measure your survivability. It focuses on how often you get hit, not how hard you hit back. For offensive stats, you would use a separate OSRS DPS calculator.

Can I use this calculator for OSRS PvP?

Yes, you can! Instead of selecting a monster, you can manually input another player’s Attack Level, prayer, stance, and Equipment Attack Bonus to see how likely they are to hit you in a PvP scenario.

How accurate are the calculations?

The calculator uses the officially recognized OSRS combat formulas. As long as you input the correct stats and equipment bonuses from your in-game screen, the resulting hit chance will be highly accurate for almost all standard combat situations.

Does the calculator account for Protection Prayers?

The main calculation shows the chance of being hit, which prayers don’t affect. However, remember that against monsters, an active Protection Prayer (e.g., Protect from Melee) reduces damage from a successful hit to 0, providing 100% damage mitigation.