OSRS BiS Calculator
An advanced tool to calculate melee DPS and find your Best-in-Slot gear in Old School RuneScape.
Player Stats & Boosts
Gear & Monster
Calculation Breakdown
| Metric | Value | Formula / Explanation |
|---|
What is an OSRS BiS Calculator?
An osrs bis calculator is a powerful tool used by players of the popular MMORPG, Old School RuneScape, to determine the “Best-in-Slot” (BiS) gear for a specific combat scenario. “Best-in-Slot” refers to the single best piece of equipment a player can wear in each slot (head, body, legs, weapon, etc.) to maximize their combat effectiveness. This effectiveness is most commonly measured in Damage Per Second (DPS), which is the primary output of any good osrs bis calculator. By inputting your character’s stats, active boosts, and target’s defensive stats, you can calculate and compare the DPS of different gear setups to make informed decisions about equipment upgrades.
This tool is essential for anyone serious about Player vs. Monster (PvM) content, from slaying bosses in God Wars Dungeon to tackling challenging raids like the Chambers of Xeric or Theatre of Blood. A common misconception is that BiS gear is always the most expensive; while often true, an osrs bis calculator can reveal budget-friendly alternatives that offer comparable performance, allowing players to optimize their setup without breaking the bank.
OSRS BiS Calculator Formula and Mathematical Explanation
The core of any osrs bis calculator is a series of complex formulas derived from the game’s mechanics by dedicated community members. The ultimate goal is to calculate DPS, which is a function of your max hit, hit chance, and attack speed. Here’s a step-by-step derivation:
- Calculate Effective Strength Level: This is your base strength level modified by potions, prayers, and attack style bonuses. For example, using Piety (23% boost) and a Super Strength Potion at 99 Strength results in a significantly higher effective level. The formula is: `floor((Strength Level + Potion Boost) * Prayer Bonus) + Style Bonus + 8`.
- Calculate Maximum Hit: Your max hit is determined by your Effective Strength and your total Melee Strength Bonus from gear. The formula is: `floor(0.5 + Effective Strength * (Strength Bonus + 64) / 640)`. This value represents the highest possible damage you can deal in a single attack.
- Calculate Player’s Max Attack Roll: Similar to the strength calculation, this determines your accuracy. It uses your Effective Attack Level (calculated similarly to strength) and your Melee Attack Bonus from gear. The formula is: `Effective Attack Level * (Attack Bonus + 64)`. A higher attack roll means a better chance to hit.
- Calculate Monster’s Max Defence Roll: This determines the monster’s ability to block your attack. It’s calculated as: `(Monster Defence Level + 9) * (Monster Slash/Stab/Crush Defence + 64)`.
- Calculate Hit Chance: This compares your attack roll to the monster’s defence roll.
- If Attack Roll > Defence Roll: `1 – (Defence Roll + 2) / (2 * (Attack Roll + 1))`
- Otherwise: `Attack Roll / (2 * (Defence Roll + 1))`
- Calculate DPS: Finally, the Damage Per Second is calculated by combining your average damage per hit with your hit chance and attack speed. The formula is: `(Max Hit / 2) * Hit Chance / (Weapon Speed * 0.6)`. This is the most crucial output of the osrs bis calculator.
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Strength Level | Your character’s base Strength skill level. | Level | 1 – 99 |
| Strength Bonus | The total Melee Strength bonus from all your worn gear. | Bonus Points | 0 – 200+ |
| Attack Bonus | The total attack bonus for your chosen style (e.g., Slash). | Bonus Points | 0 – 250+ |
| Weapon Speed | The speed of your weapon in game ticks. | Ticks | 2 – 7 |
| Monster Defence | The target monster’s base Defence skill level. | Level | 1 – 500+ |
Practical Examples (Real-World Use Cases)
Example 1: Comparing Weapons Against General Graardor
A player is preparing to fight General Graardor. They have maxed combat stats (99 Attack/Strength) and are using Piety and a Super Strength Potion. They want to know whether a Ghrazi Rapier (4-tick, +177 Attack, +123 Strength) is better than a Dragon Hunter Lance (4-tick, +140 Attack, +115 Strength), keeping in mind the lance’s 20% accuracy and damage boost against dragons (which Graardor is not).
- Rapier Inputs: Atk Lvl: 99, Str Lvl: 99, Atk Bonus: 177, Str Bonus: 123, Wep Speed: 4, Monster Def: 250.
- Rapier Output (via osrs bis calculator): ~11.5 DPS.
- Lance Inputs: Atk Lvl: 99, Str Lvl: 99, Atk Bonus: 140, Str Bonus: 115, Wep Speed: 4, Monster Def: 250.
- Lance Output (via osrs bis calculator): ~10.1 DPS.
Interpretation: The osrs bis calculator clearly shows that the Ghrazi Rapier provides significantly higher DPS against a non-dragon target like General Graardor, making it the Best-in-Slot choice here.
Example 2: Budget Setup for Vorkath
A mid-level player with 85 Ranged wants to fight Vorkath. They can’t afford a Dragon Hunter Crossbow. They use an osrs bis calculator to see if a regular Dragon Crossbow with enchanted diamond bolts (e) is a viable alternative.
- Inputs: Ranged Lvl: 85, Potion: Ranging Potion, Prayer: Eagle Eye, Gear Bonus: +120 Ranged Attack, +75 Ranged Strength, Target Def: 214, Target Magic Lvl: 150.
- Output: The calculator would show a specific DPS value. The player could then compare this to a setup with a Toxic Blowpipe to see the DPS difference and decide if the Dragon Crossbow setup meets their needs for consistent kills.
How to Use This OSRS BiS Calculator
Using this osrs bis calculator is a straightforward process designed to give you powerful insights quickly. Follow these steps:
- Enter Player Stats: Input your character’s Attack and Strength levels in the “Player Stats & Boosts” section.
- Select Boosts: Choose the potion (e.g., Super Strength) and prayer (e.g., Piety) you will be using from the dropdown menus. These significantly impact your effective combat levels.
- Input Gear Bonuses: In the “Gear & Monster” section, enter the total Melee Attack Bonus and Melee Strength Bonus from your equipment. You can find these values in your in-game equipment stats screen.
- Set Weapon Speed: Enter the attack speed of your weapon in game ticks (e.g., 4 for a whip, 5 for a godsword).
- Enter Monster Stats: Input the target monster’s Defence level. You can find this information on the OSRS Wiki.
- Analyze the Results: The calculator will instantly update. The primary result, Damage Per Second (DPS), is displayed prominently. You can also see key intermediate values like your Max Hit and Hit Chance. The table and chart provide a more detailed breakdown for deeper analysis. Use this information to compare different setups and find your Best-in-Slot gear. Check out our OSRS DPS Calculator for more options.
Key Factors That Affect OSRS BiS Calculator Results
Several critical factors influence the output of an osrs bis calculator. Understanding them is key to mastering PvM combat.
- Combat Stats (Attack, Strength, etc.): Higher levels directly increase your effective level, boosting both accuracy and damage. This is the most fundamental factor.
- Gear Bonuses (Attack & Strength): Your equipment is crucial. Attack bonus increases your accuracy, while Strength bonus increases your max hit. An osrs bis calculator helps balance these two stats for optimal DPS.
- Weapon Speed: A faster weapon attacks more often, which can often lead to higher DPS even if its max hit is lower than a slower weapon. The osrs bis calculator perfectly models this trade-off.
- Prayers: Prayers like Piety provide massive percentage-based boosts to your combat stats, dramatically increasing your DPS. They are a cornerstone of high-level PvM.
- Potions: Potions provide a temporary, flat boost to your stats, further increasing your effective combat level and overall damage output.
- Monster-Specific Gear: Items like the Slayer Helmet (on-task) or a Salve Amulet (against undead) provide enormous, situational damage and accuracy bonuses that are essential to factor into any calculation. For more info, see our PvM Gear Progression Guide.
- Target’s Defensive Stats: The higher a monster’s defence level and defensive bonuses, the lower your hit chance will be, directly reducing your DPS. This is why high-accuracy setups are vital against bosses.
- Attack Style: Your chosen attack style (e.g., Accurate, Aggressive, Defensive) can provide invisible level boosts (+3 to Attack or Strength), which are accounted for by the calculator.
Frequently Asked Questions (FAQ)
This calculator uses the community-verified combat formulas that are widely accepted as being highly accurate to the in-game mechanics. While minor discrepancies can exist due to rounding or un-polled game updates, the results are extremely reliable for comparing gear setups.
This specific tool is configured for melee calculations. The formulas for Ranged and Magic are different, involving ranged strength, magic damage %, and different effective level calculations. We have specialized tools for those combat styles, such as our Magic Max Hit Calculator.
“BiS” stands for “Best-in-Slot,” which means the single most effective item for a particular equipment slot to maximize DPS or another desired stat. What is “BiS” can change depending on the monster you’re fighting and your budget.
High-defence monsters drastically reduce your “Hit Chance.” Even with a high max hit, if you are only landing a successful hit 30% of the time, your overall damage output (DPS) will be low. This is why accuracy is just as important as strength.
Not always. While Strength Bonus directly increases your max hit, Attack Bonus is needed to actually land those hits. The best approach, which an osrs bis calculator helps with, is to find a balance. Against low-defence monsters, strength is king. Against high-defence bosses, you need to invest more in accuracy.
This calculator focuses on the DPS of basic attacks. Special attacks often have unique damage and accuracy multipliers and are not included in this standard calculation. They should be considered separately when evaluating a weapon’s overall utility. Explore our Special Attack Weapon Guide for more.
In-game, click the “Worn Equipment” icon. On the left, you will see a list of stats. The values you need for this osrs bis calculator are typically “Melee strength” and the attack bonus for your style (e.g., “Attack slash”).
Yes, you can approximate PvP DPS by entering the opponent’s Defence level and their gear’s defensive bonuses. However, PvP is more complex due to varied gear, protection prayers, and eating, so the results should be taken as a guideline, not an absolute.