Calculate your character’s Combat Maneuver Bonus for bull rush, disarm, grapple, overrun, sunder, and trip attempts.
Combat Maneuver Examples
Bull Rush
Push an opponent straight back without provoking an attack of opportunity.
Disarm
Knock an item from an opponent’s hands. You may pick it up if you have a free hand.
Grapple
Wrestle with an opponent to restrict their actions and potentially deal damage.
Overrun
Move through an opponent’s square, knocking them prone if they don’t avoid you.
Sunder
Strike an opponent’s weapon or shield to damage or destroy it.
Trip
Make an opponent fall prone. They provoke attacks of opportunity when standing.
This calculator is for Pathfinder First Edition. CMB = Base Attack Bonus + Strength modifier + size modifier + special modifiers. Always consult your GM for specific rulings.
Mastering Combat Maneuvers in Pathfinder: The Complete CMB Guide
Combat Maneuver Bonus (CMB) represents one of the most crucial mechanical systems in the Pathfinder Roleplaying Game, governing a wide range of tactical options beyond simple attack and damage. Understanding how to calculate, optimize, and effectively utilize CMB can transform your character from a basic combatant into a battlefield controller who can dictate the terms of engagement.
In Pathfinder, combat maneuvers include actions like bull rush, disarm, grapple, overrun, sunder, and trip – each offering unique tactical advantages. Your ability to perform these maneuvers successfully is determined by your CMB, while your ability to resist them is governed by your Combat Maneuver Defense (CMD).
This comprehensive guide will explore the mathematical foundations behind CMB calculations, examine class-specific optimization strategies, provide visual representations of success probabilities, and offer proven tactics for maximizing your combat effectiveness using principles similar to those in advanced CMB calculators.
Key CMB Concepts
- Understanding the CMB formula and its components
- How different classes can optimize CMB for various maneuvers
- The relationship between CMB and CMD in combat resolution
- Feats, abilities, and items that enhance combat maneuvers
CMB Fundamentals: Core Mechanics
Combat Maneuver Bonus represents your character’s proficiency at performing special combat actions that go beyond simple attacks. Understanding these fundamentals is essential for building effective martial characters and tactical combatants.
Core Components of CMB
1. Base Attack Bonus (BAB)
The foundation of CMB, representing your character’s combat training and experience. BAB progresses at different rates depending on your class and level.
2. Strength Modifier
Your Strength modifier represents physical power, which is crucial for most combat maneuvers. A high Strength score significantly boosts CMB.
3. Size Modifier
Larger creatures have an advantage in physical contests. Your size category provides a bonus or penalty to CMB: larger is better.
4. Special Modifiers
Various feats, class abilities, magic items, and situational factors can provide additional bonuses to CMB for specific maneuvers or general use.
Key Pathfinder Combat Terminology
| Term | Definition | Combat Impact |
|---|---|---|
| CMB | Combat Maneuver Bonus – Your bonus when attempting combat maneuvers | Higher CMB means better chance to succeed with maneuvers |
| CMD | Combat Maneuver Defense – Your defense against enemy maneuvers | Higher CMD makes you harder to affect with enemy maneuvers |
| BAB | Base Attack Bonus – Foundation for attack rolls and CMB | Determines how many attacks you get and contributes to CMB |
| Maneuver | Special combat action like grapple, trip, or disarm | Provides tactical options beyond dealing damage |
CMB Calculation Mathematics
The mathematics behind CMB calculations involves a straightforward formula with multiple contributing factors. Understanding this formula empowers players to build characters optimized for specific combat styles and maneuvers.
Basic CMB Formula
The fundamental CMB formula incorporates your base combat ability, physical power, and inherent advantages based on size.
CMB Formula
CMB = Base Attack Bonus + Strength Modifier + Size Modifier
Where:
- Base Attack Bonus: Determined by class and level
- Strength Modifier: Your Strength ability score modifier
- Size Modifier: Based on creature size category
Size Modifier Values
Size plays a crucial role in combat maneuvers, with larger creatures having significant advantages in physical contests.
Size Modifier Table
| Size Category | CMB Modifier | Example Creatures |
|---|---|---|
| Fine | -8 | Flea, dust mite |
| Diminutive | -4 | Mouse, bat |
| Tiny | -2 | Cat, owl |
| Small | -1 | Halfling, gnome |
| Medium | +0 | Human, elf, dwarf |
| Large | +1 | Ogre, horse |
| Huge | +2 | Elephant, giant |
| Gargantuan | +4 | Dragon, whale |
| Colossal | +8 | Kraken, tarrasque |
Combat Maneuver Resolution
When you attempt a combat maneuver, you make a CMB check against your target’s Combat Maneuver Defense (CMD).
Maneuver Success Formula
CMB Check = d20 + CMB ≥ Target’s CMD
If your CMB check equals or exceeds the target’s CMD, your maneuver succeeds. The effects vary depending on the specific maneuver attempted.
Combat Maneuvers Overview
Pathfinder features several distinct combat maneuvers, each with unique tactical applications and considerations. Understanding these maneuvers is crucial for effective battlefield control.
Major Combat Maneuvers
Each combat maneuver serves a specific purpose on the battlefield and can be enhanced by specialized feats and class abilities.
Bull Rush
- Action: Standard action
- Effect: Push enemy back 5+ feet
- Special: Can push into hazards or off cliffs
- Feats: Improved Bull Rush, Greater Bull Rush
- Best for: Controlling positioning, environmental kills
Grapple
- Action: Standard action
- Effect: Immobilizes target, limits their actions
- Special: Complex rules with multiple stages
- Feats: Improved Grapple, Greater Grapple
- Best for: Locking down single targets
Trip
- Action: Standard action
- Effect: Knocks target prone
- Special: Provokes attacks of opportunity
- Feats: Improved Trip, Greater Trip
- Best for: Setting up attacks with prone penalties
Disarm
- Action: Standard action
- Effect: Removes weapon from opponent’s hand
- Special: Provokes attacks of opportunity
- Feats: Improved Disarm, Greater Disarm
- Best for: Neutralizing weapon-dependent enemies
Additional Maneuvers
Beyond the core maneuvers, Pathfinder includes several specialized options for specific tactical situations.
| Maneuver | Action | Effect | Special Considerations |
|---|---|---|---|
| Overrun | Standard action or part of move | Move through enemy’s space | Can knock prone on success |
| Sunder | Standard action | Damage enemy’s equipment | Destroys valuable loot |
| Drag | Standard action | Move grappled opponent | Requires successful grapple first |
| Reposition | Standard action | Move enemy to different square | Doesn’t provoke like bull rush |
| Steal | Standard action | Take item from opponent | Useful for retrieving important items |
CMB Optimization Visualization
Visualizing CMB data helps players understand the relationship between character level, ability scores, and maneuver success rates. The following interactive charts demonstrate key optimization concepts and success probabilities.
CMB Progression by Class
Maneuver Success Rate vs. CR
CMB Contribution Breakdown
Tactical Insight
Visual analysis demonstrates that CMB optimization requires a multi-faceted approach. While high BAB classes like fighters have a natural advantage, any character can achieve competitive CMB values through strategic feat selection, ability score allocation, and magic items. The most effective maneuver specialists combine high Strength, appropriate size increases, and the full complement of Improved and Greater maneuver feats.
Class-Specific CMB Optimization
Different character classes have unique advantages and limitations when it comes to CMB optimization. Understanding these class-specific considerations is crucial for building effective maneuver specialists.
Martial Class CMB Strategies
| Class | BAB Progression | CMB Advantages | Optimal Maneuvers | Feat Recommendations |
|---|---|---|---|---|
| Fighter | Full (1/level) | Bonus feats, weapon training | All, especially trip and disarm | All Improved/Greater maneuver feats |
| Barbarian | Full (1/level) | Rage strength bonus, rage powers | Bull rush, overrun, sunder | Power Attack, furious focus |
| Monk | 3/4 (3/4 per level) | Bonus feats, maneuver training | Grapple, trip, reposition | Improved/Greater maneuvers, power attack |
| Brawler | Full (1/level) | Martial flexibility, brawler’s flurry | All, especially grapple and trip | Power Attack, combat expertise |
Hybrid and Specialized Classes
Several Pathfinder classes offer unique approaches to combat maneuvers through specialized abilities and alternative progression systems.
Magus
- 3/4 BAB progression
- Can deliver touch spells through weapon attacks
- Spell combat allows maneuver + spell in same round
- Optimal maneuvers: Disarm, trip
- Key abilities: Spellstrike, spell combat
Inquisitor
- 3/4 BAB progression
- Bane ability adds significant damage
- Teamwork feats without partners
- Optimal maneuvers: Trip, reposition
- Key abilities: Bane, solo tactics
Alchemist
- 3/4 BAB progression
- Mutagen provides significant strength bonus
- Discoveries can enhance specific maneuvers
- Optimal maneuvers: Grapple, trip
- Key abilities: Mutagen, discoveries
Cavalier
- Full BAB progression
- Mounted combat enhances specific maneuvers
- Challenge ability increases damage against specific foes
- Optimal maneuvers: Bull rush, overrun (mounted)
- Key abilities: Challenge, banner, orders
Feats and Abilities for CMB Optimization
Strategic feat selection and ability utilization can dramatically enhance your character’s CMB and maneuver effectiveness. Understanding these options is essential for building a capable maneuver specialist.
Core Combat Maneuver Feats
| Feat | Prerequisites | Benefits | Maneuver |
|---|---|---|---|
| Improved Bull Rush | Str 13, Power Attack | +2 CMB, no AoO when bull rushing | Bull Rush |
| Greater Bull Rush | Improved Bull Rush, BAB +6 | Enemy provokes AoO from your allies | Bull Rush |
| Improved Grapple | Dex 13, Improved Unarmed Strike | +2 CMB, no AoO when grappling | Grapple |
| Greater Grapple | Improved Grapple, BAB +6 | Maintain grapple as move action | Grapple |
| Improved Trip | Int 13, Combat Expertise | +2 CMB, no AoO when tripping | Trip |
| Greater Trip | Improved Trip, BAB +6 | Enemy provokes AoO when tripped | Trip |
General Combat Feats
Several general combat feats provide significant benefits to characters focused on combat maneuvers.
Power Attack
- Prerequisites: Str 13, BAB +1
- Benefits: Trade attack bonus for damage
- CMB Impact: Prerequisite for many maneuver feats
- Synergy: Works with all strength-based maneuvers
Combat Expertise
- Prerequisites: Int 13
- Benefits: Trade attack bonus for AC
- CMB Impact: Prerequisite for many maneuver feats
- Synergy: Defensive option for maneuver specialists
Weapon Focus
- Prerequisites: Proficiency with weapon, BAB +1
- Benefits: +1 attack with specific weapon
- CMB Impact: Improves disarm and sunder attempts
- Synergy: Required for Greater Weapon Focus
Dodge
- Prerequisites: Dex 13
- Benefits: +1 dodge bonus to AC
- CMB Impact: Prerequisite for Mobility
- Synergy: Defensive option for maneuver specialists
Magic Items for CMB Enhancement
Several magic items can significantly boost your CMB, either generally or for specific maneuvers.
CMB-Enhancing Magic Items
- Belt of Giant Strength: Direct strength increase improves CMB
- Gauntlets of the Skilled Maneuver: +2 to +5 bonus to specific maneuver
- Armor of Brawling: +2 CMB for grapple, reposition, and trip
- Weapon with Maneuver Enhancement: +1 to +5 bonus to CMB when using that weapon
- Boots of Speed: Haste effect provides extra attack for maneuvers
- Ring of Freedom of Movement: Immunity to grapple and reposition
Advanced CMB Strategies
Beyond basic optimization, experienced players use specific techniques and combinations to maximize combat maneuver effectiveness in various situations.
Teamwork and Synergy
| Strategy | Implementation | Required Resources | Effectiveness |
|---|---|---|---|
| Trip Lock | Repeatedly trip enemy to keep them prone | Improved Trip, high CMB | High – denies enemy full attacks |
| Grapple Control | Grapple then move/pin enemy | Improved Grapple, Greater Grapple | High – completely controls one enemy |
| Bull Rush Environmental | Push enemies into hazards | Improved Bull Rush, positioning | Variable – depends on environment |
| Disarm Specialist | Remove enemy weapons repeatedly | Improved Disarm, weapon bond | High vs weapon-dependent enemies |
Action Economy Optimization
Effective use of action economy can dramatically increase your maneuver effectiveness in combat.
Full-Attack Maneuvers
- Use first attack for maneuver
- Follow with regular attacks
- Best with high BAB characters
- Example: Trip → Full attack on prone enemy
- Requires: No AoO from maneuver (Improved feat)
Maneuver + Move Combinations
- Standard action for maneuver
- Move action for positioning
- Best for controlling battlefield
- Example: Bull rush → Move to better position
- Requires: Careful positioning planning
Situational Awareness
Advanced maneuver tactics require understanding and exploiting specific combat situations.
Advanced Maneuver Tactics
- Flanking Bonuses: Always maneuver with flanking for +2 bonus
- Height Advantage: Use high ground for +1 bonus to melee attacks
- Charge Maneuvers: Combine charge with bull rush or overrun for +2 bonus
- Prone Targets: +4 bonus to grapple prone opponents
- Helpless Targets: Automatic success on combat maneuvers vs. helpless
- Size Considerations: Target smaller enemies for better success rates
CMB and CMD: The Complete Picture
Understanding Combat Maneuver Defense (CMD) is just as important as understanding CMB, as it determines your vulnerability to enemy maneuvers and completes the tactical picture.
CMD Calculation
CMD represents your character’s ability to resist combat maneuvers attempted against them.
CMD Formula
CMD = 10 + Base Attack Bonus + Strength Modifier + Dexterity Modifier + Size Modifier
Where:
- Base Attack Bonus: Your base attack bonus
- Strength Modifier: Your Strength ability modifier
- Dexterity Modifier: Your Dexterity ability modifier
- Size Modifier: Based on creature size category (same as CMB table)
Additional bonuses from deflection, dodge, and other special modifiers also apply to CMD.
Improving Your CMD
Several strategies and options can significantly increase your CMD, making you more resistant to enemy maneuvers.
CMD Enhancement Strategies
- Increase Dexterity: Directly improves CMD
- Dodge Bonuses: Dodge feat, class abilities
- Deflection Bonuses: Rings of protection, magic armor
- Size Increases: Larger size categories improve CMD
- Feats: Improved/Greater maneuver feats often provide CMD bonuses
- Class Abilities: Monk wisdom to CMD, fighter armor training
CMB vs CMD Balance
| Character Type | Typical CMB | Typical CMD | Maneuver Vulnerability |
|---|---|---|---|
| Heavy Armor Fighter | High | High | Low – good at both maneuvers and defense |
| Dexterity Rogue | Low | High | Low defense – high CMD protects them |
| Strength Barbarian | Very High | Medium | Medium – great at maneuvers, average defense |
| Wizard | Very Low | Very Low | High – vulnerable to all maneuvers |
Conclusion
Mastering Combat Maneuver Bonus calculations in Pathfinder requires understanding both the mathematical foundations and practical combat applications. The relationship between CMB, CMD, and specific maneuver feats follows predictable patterns that can be optimized for maximum battlefield control.
From the basic CMB formula to advanced tactical combinations, combat maneuver mathematics provides a framework for comparing character builds, predicting success probabilities, and developing winning strategies. Visualization tools further enhance understanding by illustrating how different factors affect maneuver success rates and character effectiveness.
Whether you’re building a dedicated maneuver specialist or adding tactical options to an existing character, mastering CMB calculations enables you to approach Pathfinder combat with strategic depth. By understanding the mathematical foundations, considering class-specific optimization paths, and implementing proven feat selections, you can maximize your combat effectiveness and control the battlefield throughout your adventuring career.
Frequently Asked Questions
Below are answers to common questions about CMB calculations, maneuver strategies, and Pathfinder combat mechanics.
The basic Combat Maneuver Bonus formula is:
CMB = Base Attack Bonus + Strength Modifier + Size Modifier
Where:
- Base Attack Bonus: Determined by your class and level
- Strength Modifier: Your Strength ability score modifier
- Size Modifier: Based on your size category (from -8 for Fine to +8 for Colossal)
Additional bonuses from feats, magic items, and class abilities are added to this base value.
To perform a combat maneuver:
- Declare you are attempting a maneuver
- Make a CMB check: roll d20 + your CMB
- Compare the result to the target’s Combat Maneuver Defense (CMD)
- If your result equals or exceeds the target’s CMD, the maneuver succeeds
Most combat maneuvers are standard actions, though some can be performed as part of other actions (like overrun during movement).
CMB and CMD represent two sides of the combat maneuver system:
- CMB (Combat Maneuver Bonus): Your bonus when attempting combat maneuvers against others
- CMD (Combat Maneuver Defense): Your defense against combat maneuvers attempted against you
The formulas are similar but not identical:
CMB = BAB + Str modifier + size modifier
CMD = 10 + BAB + Str modifier + Dex modifier + size modifier
Notice that CMD has a base of 10 and includes your Dexterity modifier.
Most combat maneuvers do provoke attacks of opportunity, unless you have the appropriate feat:
- Without Improved feat: The maneuver provokes an attack of opportunity
- With Improved feat: The maneuver does not provoke an attack of opportunity
For example, attempting a trip without Improved Trip provokes an attack of opportunity from the target. With Improved Trip, it does not.
This is why the Improved maneuver feats are so important for maneuver-focused characters.
Yes, many combat maneuvers can be performed with weapons, and some even require them:
- Disarm: Requires a weapon (or unarmed strike)
- Sunder: Requires a weapon
- Trip: Can be done with a weapon (if it has the trip property) or unarmed
- Grapple: Typically done unarmed, though some weapons allow it
- Bull Rush, Overrun: Typically done without weapons
When using a weapon for a maneuver, you typically use that weapon’s enhancement bonus as a bonus to your CMB check for that maneuver.
Several classes excel at combat maneuvers:
- Fighter: Full BAB, bonus feats for maneuver chains
- Barbarian: Full BAB, rage strength bonus
- Brawler: Full BAB, martial flexibility for situational feats
- Monk: Good BAB, bonus feats, maneuver training class feature
- Inquisitor: Good BAB, bane ability for damage, teamwork feats
Any class with full BAB progression can be effective with combat maneuvers, but fighters have the advantage of bonus feats to complete feat chains quickly.
Size is extremely important for combat maneuvers:
- Each size category difference provides a +4/-4 bonus/penalty to CMB and CMD
- Larger creatures have significant advantages in physical contests
- You cannot grapple creatures more than one size category larger than you
- Some maneuvers have additional restrictions based on size
This is why spells like Enlarge Person are so valuable for maneuver-focused characters – they provide a size increase that directly improves CMB.
Yes, there are several ways to attempt multiple maneuvers in one round:
- Full Attack: Use your first attack for a maneuver, then make remaining attacks normally
- Rapid Grappler: With Greater Grapple, you can maintain a grapple as a move action and attempt another as a standard
- Two-Weapon Fighting: With appropriate feats, you can attempt maneuvers with off-hand attacks
- Certain Class Abilities: Some classes have abilities that allow additional maneuvers
Remember that most maneuvers are standard actions, so without special abilities or feats, you’re limited to one maneuver per round.