Runescape Combat Calculator

OSRS Combat Calculator

Estimate your Max Hit, Accuracy, and DPS in Old School RuneScape. Fill in your stats and gear bonuses below.

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Opponent Stats

Results Table & Chart

Scenario	Effective Str	Max Hit	Accuracy (%)	DPS
Fill inputs and calculate…

Table: Estimated combat performance with different boosts against the opponent.

Chart: Accuracy vs. Opponent Defence Bonus

What is a RuneScape Combat Calculator?

A RuneScape Combat Calculator is a tool designed to help players of Old School RuneScape (OSRS) and sometimes RuneScape 3 (RS3) estimate their combat effectiveness against various monsters or other players. It takes into account your character’s combat stats (Attack, Strength, Defence levels), the bonuses provided by your gear, active prayers, potions, and attack style, as well as the stats of your opponent. The primary outputs are usually your maximum hit (Max Hit), your accuracy against the target, and your Damage Per Second (DPS). This RuneScape Combat Calculator focuses on OSRS melee combat.

Anyone looking to optimize their combat performance should use a RuneScape Combat Calculator. This includes players engaging in Player vs. Monster (PvM) activities like bossing or Slayer, or Player vs. Player (PvP) combat. It helps in gear selection, training decisions, and understanding how different factors influence damage output.

Common misconceptions are that these calculators are 100% accurate for every hit (they predict averages and maximums, individual hits vary due to RNG) or that they include every single niche bonus (most cover common and significant boosts). Our RuneScape Combat Calculator provides a good estimate based on standard formulas.

RuneScape Combat Calculator Formula and Mathematical Explanation

The core calculations in a RuneScape Combat Calculator for OSRS melee involve determining Effective Attack and Strength levels, Max Hit, Max Attack Roll, Max Defence Roll, and finally Accuracy and DPS.

1. Effective Levels:

Effective Strength (Eff Str) and Effective Attack (Eff Att) are calculated first:

Eff Str = floor((Base Str + Potion Boost) * Prayer Bonus * Other Bonus) + Style Bonus + 8

Eff Att = floor((Base Att + Potion Boost) * Prayer Bonus * Other Bonus) + Style Bonus + 8

Potion boosts (like Super Strength), prayer bonuses (like Piety), and ‘Other Bonuses’ (like Slayer Helm) are applied multiplicatively to the base level + potion increase, then style bonus and a base of +8 are added.

2. Max Hit:

Max Hit = floor(0.5 + Eff Str * (Gear Str Bonus + 64) / 640)

The Max Hit is based on the Effective Strength level and the total Strength bonus from your equipment.

3. Max Rolls:

Max Attack Roll = Eff Att * (Gear Att Bonus + 64)

Max Defence Roll = Effective Opponent Defence * (Opponent Defence Bonus + 64)

Effective Opponent Defence is calculated similarly to player effective levels, considering their base Defence level and bonuses.

4. Accuracy:

If Max Attack Roll > Max Defence Roll:

Accuracy = 1 - (Max Defence Roll + 2) / (2 * (Max Attack Roll + 1))

If Max Attack Roll <= Max Defence Roll:

Accuracy = Max Attack Roll / (2 * (Max Defence Roll + 1))

This gives the probability of successfully hitting the opponent.

5. Damage Per Second (DPS):

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

Weapon speed is given in ticks (1 tick = 0.6 seconds). Average damage per hit is Max Hit / 2 (assuming damage is uniformly distributed from 0 to Max Hit).

Variables Table:

Variable	Meaning	Unit	Typical Range
Base Str/Att	Player’s base Strength/Attack level	Level	1 – 99
Potion Boost	Increase from potions (e.g., Super Strength)	Level/Percentage	0 – ~19 (for 99)
Prayer Bonus	Multiplier from prayers (e.g., Piety)	Multiplier	1.0 – 1.23
Other Bonus	Multipliers like Slayer Helm, Salve	Multiplier	1.0 – 1.20
Style Bonus	Bonus from attack style	Level	0, 1, or 3
Gear Str/Att Bonus	Sum of bonuses from equipment	Bonus Points	0 – 200+
Weapon Speed	Time between attacks	Ticks (0.6s)	2 – 7
Opponent Defence	Opponent’s base Defence level	Level	1 – 500+
Opponent Defence Bonus	Opponent’s gear defence bonus	Bonus Points	0 – 300+

Practical Examples (Real-World Use Cases)

Example 1: Mid-Level Player vs. Slayer Monster

A player with 75 Attack, 80 Strength, using a Dragon Scimitar (+67 Attack, +66 Strength, 4 ticks), fighting a monster with 70 Defence and +50 Defence bonus. The player uses Super Strength and Piety, on a Slayer task with a Slayer Helm.

• Inputs: Att 75, Str 80, Att Bonus 67, Str Bonus 100 (incl. other gear), Wpn Speed 4, Opp Def 70, Opp Def Bonus 50, Super Str, Piety, Slayer Helm, Aggressive Style.
• Expected Outputs: The RuneScape Combat Calculator would show a significantly increased Max Hit and DPS due to all boosts combined, with high accuracy against the mid-level monster.

Example 2: High-Level Player vs. Boss

A player with 99 Attack, 99 Strength, using a Ghrazi Rapier (+94 Attack, +89 Strength, 4 ticks) against a boss with 250 Defence and +150 Defence bonus. The player uses Super Combat Potion and Piety.

• Inputs: Att 99, Str 99, Att Bonus ~150 (Rapier + gear), Str Bonus ~140, Wpn Speed 4, Opp Def 250, Opp Def Bonus 150, Super Combat (Super Str effect), Piety, Aggressive Style.
• Expected Outputs: The RuneScape Combat Calculator would show a high Max Hit but potentially lower accuracy due to the boss’s high defence, resulting in a specific DPS value crucial for boss fight planning.

How to Use This RuneScape Combat Calculator

1. Enter Your Levels: Input your Attack and Strength levels.
2. Enter Gear Bonuses: Input the total Attack and Strength bonuses from all your equipped gear (including weapon).
3. Weapon Speed: Enter your weapon’s speed in ticks (e.g., 4 for scimitar/whip).
4. Select Attack Style: Choose your combat style (Accurate, Aggressive, etc.).
5. Select Boosts: Check the boxes for any active potions (Super Strength/Combat), prayers (Piety/Chivalry), or other modifiers like Slayer Helm/Salve Amulet.
6. Enter Opponent Stats: Input the Defence level and Defence bonus of your target.
7. Calculate: Click “Calculate” or observe the results update as you change inputs.
8. Read Results: The calculator displays Max Hit, Accuracy, DPS, and intermediate values. The table and chart provide more context.
9. Decision-Making: Use the results to compare gear setups, prayer usage, or to see if you meet DPS checks for certain bosses.

Key Factors That Affect RuneScape Combat Calculator Results

• Combat Levels (Attack, Strength): Higher levels directly increase effective levels and thus max hit and attack roll.
• Gear Bonuses (Attack, Strength): The bonuses from your weapon and armour are crucial for both max hit and accuracy. Higher bonuses mean higher rolls.
• Prayers: Prayers like Piety provide significant percentage-based boosts to Attack and Strength levels, dramatically increasing DPS.
• Potions: Potions like Super Strength provide temporary level boosts, increasing effective levels.
• Attack Style: Provides small, invisible level boosts to Attack, Strength, or Defence.
• Opponent’s Defence: A higher opponent Defence level and Defence bonus reduce your accuracy, lowering DPS.
• Weapon Speed: Faster weapons (lower tick count) attack more often, which can lead to higher DPS even with a lower max hit, provided accuracy is good.
• Special Modifiers: Items like the Slayer Helmet (on task) or Salve Amulet (vs undead) give substantial damage and accuracy boosts.

Understanding these factors allows you to make informed decisions when using the RuneScape Combat Calculator to optimize your setup.

Frequently Asked Questions (FAQ)

Q1: How accurate is this RuneScape Combat Calculator?

A1: It’s based on widely accepted OSRS combat formulas and provides a very good estimate for average and max damage. However, actual combat involves Random Number Generation (RNG), so individual hits will vary.

Q2: Does this calculator work for RS3?

A2: No, this calculator is specifically designed using OSRS (Old School RuneScape) combat mechanics. RS3 has a different combat system (EoC).

Q3: Are all prayers and potions included?

A3: We include common melee boosts like Super Strength (or Combat potions which include it) and Piety/Chivalry. More niche potions or prayers might not be explicitly listed but their effects can sometimes be manually approximated if you know the stat boosts.

Q4: How do I find my gear’s Attack and Strength bonuses?

A4: In OSRS, open the “Worn Equipment” interface, and at the bottom, click the button showing a character with stats. This will display your total bonuses from equipped items.

Q5: What about ranged or magic combat?

A5: This specific RuneScape Combat Calculator focuses on melee. Ranged and Magic have different formulas for max hit and accuracy involving Ranged/Magic levels and bonuses.

Q6: How important is weapon speed?

A6: Very important. A faster weapon might have a lower max hit but can result in higher DPS because it attacks more frequently.

Q7: Why does accuracy change so much with opponent defence?

A7: Accuracy is calculated by comparing your attack roll against the opponent’s defence roll. Higher opponent defence significantly increases their defence roll, making it harder for your attack roll to succeed.

Q8: Can I use this for PvP?

A8: Yes, if you input the opponent player’s Defence level and approximate Defence bonus from their gear, you can get an estimate of your effectiveness against them.