Inventory Weight

Inventory Weight is a realistic encumbrance system mod for Minecraft that applies movement penalties based on how heavy your inventory is. Every item has a weight, and carrying too much will slow you down, reduce your jump height, drain your stamina, and even attract hostile mobs.

The goal is immersive survival gameplay where inventory management matters. Pack light to stay agile, or load up on gear and accept the consequences. The mod provides rich feedback through HUD elements, sounds, particles, and status effects to keep you aware of your burden.

Key Features

• Dynamic weight system - Every item has a weight based on its material (ores, ingots, tools, food, etc.).
• Five-tier penalty system - Progressive penalties from Light (no effect) to Crippled (barely mobile).
• Movement penalties - Affects walking speed, sprint speed, jump height, swimming, and climbing.
• Combat impact - Attack speed slows and fall damage increases when overloaded.
• Stamina system - Optional stamina bar that drains faster when heavily encumbered.
• Elytra penalties - Heavier loads cause faster descent during gliding.
• Mob detection - Heavy footsteps increase hostile mob detection range.
• Dimension modifiers - Weight feels different in the Nether (heavier) and End (lighter).
• Transport exceptions - Horses, minecarts, and boats reduce or eliminate penalties.
• Rich feedback - Tier change sounds, particles, action bar messages, and status effects.
• Advancement system - Unlock achievements for weight-related accomplishments.
• Fully configurable - All weights, thresholds, and behaviors can be customized via JSON.

How It Works

Weight Calculation

Every 10 ticks (0.5 seconds), the mod calculates your total inventory weight:

Weight Categories

Items are automatically categorized based on their name and properties:

Weight Tiers

Your total weight determines your tier, which sets all penalty multipliers:

Penalty Breakdown

Stamina System

When enabled, adds an optional stamina mechanic that drains during strenuous activities:

Stamina by Tier

A stamina bar appears on-screen when enabled (position configurable).

Elytra Flight

Weight significantly impacts elytra gliding performance:

Heavy players will need more rockets and struggle to glide long distances.

Mob Detection System

Heavier loads make you easier to detect by hostile mobs:

Detection Radius by Tier

Dimension & Environment Modifiers

Weight feels different depending on where you are:

Dimension Multipliers

Environmental Effects

Transport Exceptions

Certain vehicles reduce or eliminate weight penalties:

This encourages using mounts for long-distance travel when heavily loaded.

Feedback System

The mod provides extensive feedback to keep you informed:

Visual Feedback

Audio Feedback

Status Effects (Optional)

Advancements

Unlock achievements for weight-related accomplishments:

Statistics Tracking

The mod tracks your weight-related statistics:

View your stats with /weight stats.

Commands

Configuration

Config file location: .minecraft/config/inventoryweight.json

The config file is created automatically on first launch. All options:

{
  "enabled": true,
  "showHud": true,
  "hotbarWeightMultiplier": 1.25,
  "hardcoreMode": false,
  "hardcoreMultiplier": 1.5,
  "lightTierThreshold": 0.0,
  "mediumTierThreshold": 50.0,
  "heavyTierThreshold": 100.0,
  "overloadedTierThreshold": 175.0,
  "crippledTierThreshold": 250.0,
  "categoryWeightHeavy": 5.0,
  "categoryWeightMedium": 2.0,
  "categoryWeightLight": 0.5,
  "categoryWeightNearZero": 0.1,
  "horseIgnoresWeight": true,
  "minecartIgnoresWeight": true,
  "boatPartiallyIgnoresWeight": true,
  "boatWeightReduction": 0.5,
  "showWeightInTooltip": true,
  "weightAffectsSwimming": true,
  "weightAffectsClimbing": true,
  "weightAffectsFallDamage": true,
  "weightCausesExhaustion": true,
  "weightAffectsMining": true,
  "weightAffectsAttackSpeed": true,
  "weightAffectsElytra": true,
  "shulkerBoxAddsContentWeight": true,
  "shulkerBoxBaseWeight": 3.0,
  "shulkerContentWeightMultiplier": 0.5,
  "playTierChangeSounds": true,
  "showTierChangeParticles": true,
  "staminaEnabled": false,
  "maxStamina": 100.0,
  "baseStaminaDrain": 1.0,
  "baseStaminaRegen": 0.5,
  "showStaminaBar": true,
  "staminaBarX": 10,
  "staminaBarY": 60,
  "dimensionModifiersEnabled": true,
  "netherWeightMultiplier": 1.15,
  "endWeightMultiplier": 0.85,
  "overworldWeightMultiplier": 1.0,
  "waterDepthPenaltyEnabled": true,
  "rainWeightMultiplier": 1.1,
  "altitudeModifierEnabled": true,
  "mobDetectionEnabled": true,
  "baseDetectionRadius": 16.0,
  "footstepVolumeEnabled": true,
  "weightAppliesStatusEffects": false,
  "slownessAtOverloaded": true,
  "miningFatigueAtCrippled": true,
  "speedBoostWhenLight": false,
  "customItemWeights": {}
}

Config Options Explained

Custom Item Weights

Override any item's weight with custom values in the config:

{
  "customItemWeights": {
    "minecraft:anvil": 15.0,
    "minecraft:netherite_block": 20.0,
    "minecraft:feather": 0.05,
    "modid:custom_item": 3.0
  }
}

Multiplayer Compatibility

This mod works on both client and server. For full functionality:

For the best experience, install on both client and server.

Multiplayer Features

• Weight calculations are done server-side for security
• Movement modifiers use vanilla attribute system
• Per-player weight data stored in concurrent hash maps
• State synchronized properly between client and server

Installation

1. Install Fabric Loader (0.15.6 or newer) for Minecraft 1.20.1.
2. Install Fabric API (0.92.0+1.20.1 or newer).
3. Download the mod JAR file.
4. Place the JAR into your .minecraft/mods folder.
5. Launch Minecraft with the Fabric profile.

Building from Source

Clone the repository and run the Gradle build:

git clone https://github.com/AaravVishal1/Inventory-Weight
cd Inventory-Weight
./gradlew build

The compiled JAR will be in build/libs/.

For development, you can run the client directly:

./gradlew runClient

Requirements

Troubleshooting

Movement speed isn't affected

1. Check that the mod is enabled (/weight toggle).
2. Verify you're not in Creative or Spectator mode.
3. Make sure you're not riding a horse/minecart (transport exception).
4. Check your weight with /weight check to see your current tier.

Weight seems too punishing

• Lower the tier thresholds in the config to require more weight.
• Reduce category weights for item types you carry often.
• Disable hardcore mode if enabled.
• Disable individual penalties (swimming, climbing, etc.) as needed.

Stamina drains too fast

• Reduce baseStaminaDrain in the config.
• Increase maxStamina for a larger pool.
• Carry lighter loads more often.

HUD/tooltips not showing

• Enable showHud and showWeightInTooltip in config.
• Make sure you have the client-side mod installed.
• Try reloading with /weight reload.

Items have wrong weights

• Use /weight set <item> <weight> to assign custom weights.
• Edit customItemWeights in the config file directly.
• Category assignment is based on item name keywords.

Mod conflicts with other mods

• The mod uses standard Fabric events and mixins.
• If another mod modifies player movement, there may be conflicts.
• Report issues with specific mod combinations.

Technical Details

Performance

• Weight recalculated every 10 ticks (0.5 seconds)
• Immediate recalculation on inventory change events
• Minimal performance impact during normal gameplay

Mixins Used

Compatibility

• Compatible with most Fabric mods
• Uses standard Fabric events and mixins
• Does not modify vanilla items or add new content
• Works with modded items (auto-categorized by name)

License

This project is licensed under the MIT License.