OSRS Damage Calculator (Melee)

Calculate your Max Hit, Accuracy, and DPS in Old School RuneScape.

Max Hit Comparison (With Prayers)

A chart comparing your max hit with different strength prayers.

What is an OSRS Damage Calculator?

An osrs damage calculator is a vital tool for any serious Old School RuneScape player looking to optimize their combat performance. It allows you to simulate your damage output by inputting various stats, gear bonuses, and active buffs like potions and prayers. Instead of relying on guesswork, this calculator provides precise metrics such as your maximum possible hit (Max Hit), your chance to successfully hit an opponent (Accuracy), and your overall Damage Per Second (DPS). By understanding these numbers, players can make informed decisions about which gear to buy, what prayers to use, and how to approach different monsters or PvP situations for maximum efficiency.

This type of calculator is not just for high-level players. Mid-level players can use an osrs damage calculator to determine if a new weapon is a worthwhile upgrade or how much a few extra Strength levels will impact their training. For anyone serious about bossing, slayer, or Player vs. Player combat, using a damage calculator is the first step in advanced theorycrafting. You can find more about slayer in our OSRS Slayer Guide.

The OSRS Damage Calculator Formula and Explanation

The core of any osrs damage calculator revolves around a series of formulas defined by the game’s mechanics. While they might seem complex, they can be broken down into logical steps to determine your final damage output.

1. Effective Level Calculation

First, we calculate your ‘Effective’ Attack and Strength levels. This isn’t just your base stat; it’s your level after boosts from potions, prayers, and attack styles are applied.

Effective Strength = floor((Strength Level + Potion Boost) * Prayer Bonus) + Style Bonus + 8

Effective Attack = floor((Attack Level + Potion Boost) * Prayer Bonus) + Style Bonus + 8

2. Max Hit Calculation

Next, the calculator determines your base max hit using your Effective Strength and total Melee Strength bonus from gear.

Base Max Hit = floor(0.5 + Effective Strength * (Strength Bonus + 64) / 640)

Finally, this base hit is multiplied by any special gear bonuses, like a Slayer Helmet or Void Knight set.

Final Max Hit = floor(Base Max Hit * Special Gear Bonus)

3. Accuracy and DPS Calculation

To find your accuracy, the calculator computes your maximum Attack Roll and compares it to the opponent’s maximum Defence Roll.

Max Attack Roll = Effective Attack * (Attack Bonus + 64)

Max Defence Roll = (Monster Defence Level + 9) * (Monster Defence Bonus + 64)

The probability of hitting is then calculated based on which roll is higher. This hit chance, combined with your max hit and weapon speed, gives the final DPS value.

DPS = (Max Hit / 2) * Accuracy / Weapon Speed (seconds)

Variable Explanations

Variable	Meaning	Unit	Typical Range
Strength Level	Your base Strength skill level.	Level	1 – 99
Strength Bonus	The “Melee strength” value from your gear.	Points	0 – 200+
Prayer Bonus	The percentage multiplier from a prayer (e.g., Piety is 1.23).	Multiplier	1.0 – 1.23
Weapon Speed	The speed of your weapon in game ticks.	Ticks	2 – 7

Practical Examples

Example 1: Mid-Level Slayer Task

A player is on a slayer task for Aberrant Spectres with a Black Mask. They want to see their potential with a Dragon Scimitar.

• Inputs: Attack: 75, Strength: 80, Super Strength Potion, Protect from Magic, Ultimate Strength prayer, Aggressive style, Dragon Scimitar (Attack +67, Strength +66, Speed 4), Black Mask (i) bonus. Monster Defence: 110, Monster Defence Bonus: +0.
• Results: This player’s osrs damage calculator would show a significant Max Hit and DPS increase due to the slayer helm bonus, making the task much faster.

Example 2: High-Level Bossing

A maxed player is fighting General Graardor with a Ghrazi Rapier. They are using Piety and an Overload potion.

• Inputs: Attack: 99, Strength: 99, Overload Potion, Piety, Aggressive style, Ghrazi Rapier (Attack +94, Strength +89, Speed 4). Monster Defence: 250, Monster Stab Defence Bonus: +90.
• Results: The calculator would show their max hit, their accuracy against Graardor’s high defence, and their final DPS. This helps them compare the rapier to other weapons like a Scythe of Vitur. For more comparisons, check out our osrs dps calculator tool.

How to Use This OSRS Damage Calculator

1. Enter Your Base Stats: Input your character’s visible Attack and Strength levels.
2. Select Your Boosts: Choose the potions and prayers you are using. The calculator automatically applies the correct percentage boosts.
3. Input Equipment Bonuses: Look at your “Worn Equipment” screen in-game and enter the total Melee Attack and Melee Strength bonuses. Do not forget to select your attack style.
4. Add Special Gear: If you’re using gear like a Slayer Helmet or Void set, select it from the dropdown to apply the special multiplier.
5. Enter Target’s Stats: Input the monster’s Defence level and its specific defence bonus against your attack style (e.g., Stab, Slash, Crush).
6. Analyze the Results: The osrs damage calculator will instantly update your Max Hit, Accuracy, and DPS. Use these numbers to theorycraft your best setup!

Key Factors That Affect OSRS Damage

• Strength Level: The single most important factor for increasing your max hit. Each strength level provides a noticeable boost.
• Strength Bonus: The total strength bonus from your gear is directly multiplied in the damage formula. Getting a +1 strength bonus is often a bigger upgrade than several attack bonus points. Our osrs max hit calculator can help you see this difference.
• Prayers: Prayers like Piety provide a massive percentage-based boost to both strength and attack, making them essential for high-level combat.
• Potions: Super strength and overload potions provide a temporary but significant level boost, pushing your damage potential higher.
• Attack Style: Using an “Aggressive” style provides +3 to your strength level for the calculation, a free and easy damage boost.
• Opponent’s Defence: Your accuracy, and therefore your DPS, is highly dependent on the monster’s defence level and bonus. Against low-defence monsters, strength bonus is king. Against high-defence bosses, attack bonus becomes much more valuable.

Frequently Asked Questions (FAQ)

1. How is accuracy calculated in OSRS?

Accuracy is a roll of your Attack value against your opponent’s Defence value. The osrs damage calculator determines your maximum possible roll and compares it to the opponent’s to find the probability of a successful hit.

2. Is Attack or Strength more important?

For raw damage (Max Hit), Strength is more important. For consistency (Accuracy), Attack is more important. The best balance depends on your target.

3. Does this calculator work for Ranged or Magic?

This specific tool is configured for Melee. The formulas for Ranged and Magic are similar but use different stats (Ranged/Magic level), bonuses (Ranged Strength), and prayers (Eagle Eye/Mystic Might).

4. What does DPS mean?

DPS stands for Damage Per Second. It is the most important metric for measuring combat effectiveness over time, as it accounts for your max hit, accuracy, and attack speed. A higher DPS means you will kill the monster faster.

5. Why is my max hit not changing when I add +1 strength bonus?

The max hit formula involves division and rounding down. Sometimes, a small increase in strength bonus isn’t enough to push the result over the next whole number threshold. It might take +2 or +3 strength bonus to see a new max hit.

6. Does weapon speed affect my max hit?

No, weapon speed does not affect your max hit. However, it is a crucial component of your DPS. A faster weapon will attack more often, leading to higher DPS even if the max hit is lower than a slower weapon.

7. How accurate is this osrs damage calculator?

This calculator uses the widely accepted combat formulas from the OSRS community. It is highly accurate for standard melee combat scenarios without complex special attack mechanics.

8. Where can I find monster defence stats?

The best resource is the Official OSRS Wiki. Search for your target monster and look at its combat stats to find its Defence level and specific defensive bonuses.