OSRS Armor Calculator
Estimate effective defence rolls, incoming hit chance, and gear setup differences for stab, slash, crush, ranged, and magic attacks.
🛡Gear Presets
⚔Defence Inputs
Armor Defence Estimate
📊Current Defence Bonus Grid
🔁Gear Setup Comparison
| Metric | Current Setup | Comparison Setup | Difference |
|---|---|---|---|
| Selected style roll | - | - | - |
| Enemy hit chance | - | - | - |
| Best defence style | - | - | - |
| Weakest defence style | - | - | - |
⚙Reference: Defence Roll Formula
| Step | Formula Piece | What It Uses | Why It Matters |
|---|---|---|---|
| Effective defence | Level x prayer + stance + 8 | Defence, prayer, stance | Raises every style roll before gear is applied. |
| Magic defence | Weighted defence level | Defence and Magic levels | Magic attacks care about Magic level more than melee styles do. |
| Defence roll | Effective x (bonus + 64) | Chosen style bonus | The main number compared against an enemy attack roll. |
| Hit chance | OSRS accuracy curve | Attack roll vs defence roll | Turns the two rolls into an estimated chance to be hit. |
🧪Reference: Preset Defence Bonuses
| Preset | Strongest Style | Typical Weakness | Primary Use |
|---|---|---|---|
| Rune F2P Tank | Slash | Magic | Free-to-play melee tanking and simple melee threats. |
| Barrows Melee Bulwark | Slash | Magic | General melee bossing where magic damage is limited. |
| Torva Max Melee | Slash | Magic | High-stat melee armour with strong mixed melee defence. |
| Justiciar Boss Tank | Slash | Magic | Defence-heavy tanking where damage reduction matters. |
| Karil Magic Screen | Magic | Crush | Magic-heavy encounters needing better magic defence. |
| Armadyl Range Defence | Ranged | Crush | Ranged setups that still need incoming ranged protection. |
🎯Reference: Enemy Attack Profiles
| Enemy Profile | Attack Level | Attack Bonus | Use In Calculator |
|---|---|---|---|
| Low quest monster | 45 | 25 | Early testing or low-combat accounts. |
| Slayer task brute | 120 | 75 | Common melee pressure from regular PvM. |
| Boss melee swing | 180 | 115 | Mid-to-high boss melee accuracy checks. |
| Raid ranged attack | 220 | 145 | High-end ranged attack pressure. |
| Magic boss cast | 240 | 160 | Magic defence checks with high Magic level value. |
| Special attack roll | 280 | 190 | Use with an empowered or special multiplier. |
💡Calculation Tips
Old School RuneScape allow players to select a defense levels for there character. However, there isnt no single defense numbers in RuneScape. Instead, there is five attack styles for players to separate their defense numbers.
When enemies attacks, they use one attack style. Only the defense number for that specific attack style will have any influence on the player. For example, if the enemy use a stab attack, then only the player’s stab defense will factor into the outcome of the combat.
How Defense Works in Old School RuneScape
Switching to a piece of equipment that improve a different attack style, such as crush defense, will not impact the damage taken from a stab attack. Magic defense are another distinct defense value for RuneScape players. Unlike the other defense stats, magic defense use two different values to determine the defense level of a RuneScape player.
The magic defense value is based off a player’s magic level and defense level. For this reason, a RuneScape player that has high defense in melee attacks may still take a significant amount of damage from magic attacks. When a player choose an attack style in the defense calculator, the defense calculator will use that specific defense value to calculate the outcome of the attacks.
Besides defense values, there are two additional attributes that may impact the outcome of combat in RuneScape: stance and prayer bonuses. Both of these attributes will increase the defense rolls that a RuneScape player take before the attacks are made against the player. The prayer bonus increases the effective defense level of a player prior to there defense bonuses from there equipment.
This means that a player that use a prayer will have more defense from their armor. Additionally, a defensive stance will provide bonus defense rolls. These two attributes will compound each other.
For instance, a player might use a stance and prayer that may change a 55% chance of landing an attack to a 35% chance. This means that the player will require less food to withstand the attacks in the encounter. The game also have a comparison feature in the defense calculator.
This feature is presented in response to the fact that when changing one item in a player’s equipment, it does not necessarily improve the defense against each of the attack styles. A set of armor may have a high defense against all attack types but may have low defense against the one that the enemy use. Using the comparison feature, the player can compare the defense of the same enemy using two different sets of equipment.
The reference tables will help a player understand the trade-offs between the two set of equipment. RuneScape players may make a few mistakes when equipping their items. Most players will focus on total defense but ignore magic defense.
For example, they may wear items with high melee defense but low magic defense. In this case, the player will take many damage from magic attacks. Alternatively, players may wear armor with high magic defense but low defense in other attack styles.
In these instances, players will be taken alot of damage from other attack types. The defense calculator help to avoid these mistakes. It require the player to select the attack style to calculate the defense before the player sees the results.
The defense rating that the defense calculator presents players can be used to translate the percentage chance of the defense rolls into a simple category. A fortress rating means that the enemy attacks are unlikely to land on the player. In contrast, an exposed rating means that the attacks are likely to land on the player.
An exposed rating indicate that a player should of adjust their prayer, stance, or equipment prior to the fight. Although the defense calculator will calculate the defense rolls, it cannot account for the player’s decisions. A RuneScape player might choose weaker equipment that allow them to switch prayers or fight fasterer to achieve there game goal.
