Void Fill Guide: Minimize Wasted Space and Damage
Void fill should occupy 15-25% of package volume for most products, using materials appropriate to product fragility and value. The optimal approach is right-sizing boxes first (reducing void to fill), then selecting materials based on protection needs: air pillows for moderate protection, kraft paper for light cushioning, foam for fragile items, and custom inserts for high-volume SKUs. Over-packing is as problematic as under-packing—excess void fill increases box size, DIM weight, material costs, and shipping expenses. The best void fill strategy is one that minimizes empty space while providing adequate protection.
Every inch of empty space in your packages is a problem. Too much void fill wastes money and increases DIM weight. Too little risks damage and returns.
The goal isn't eliminating void fill—it's optimizing it. The right amount of the right material, placed correctly, protects your product without inflating shipping costs.
This guide covers void fill materials, quantity calculations, placement techniques, and cost optimization strategies.
Understanding Void Fill
What Void Fill Does
Three protective functions:
| Function | How It Works |
|---|---|
| Cushioning | Absorbs impact energy during drops and collisions |
| Blocking | Prevents product movement within the box |
| Bracing | Keeps product away from box walls |
The Void Fill Paradox
More isn't always better:
| Too Little Void Fill | Too Much Void Fill |
|---|---|
| Product moves in box | Requires larger box |
| Impacts box walls | Higher DIM weight |
| Damage risk increases | Material cost increases |
| Returns increase | Shipping cost increases |
The goal: minimum void fill that provides adequate protection.
Void Fill Materials
Air Pillows
Best for: moderate protection, space efficiency
| Pros | Cons |
|---|---|
| Lightweight | Can pop/deflate |
| Cost-effective | Limited cushioning for fragile items |
| Easy to use | Requires inflation equipment |
| Recyclable | Customer perception issues |
Specifications:
- Protection level: Moderate
- Cost: $0.02-0.05 per pillow
- Best use: Gap filling, light blocking
Kraft Paper (Crinkle Paper)
Best for: light cushioning, sustainability messaging
| Pros | Cons |
|---|---|
| Sustainable | Heavier than air pillows |
| Good perception | Less cushioning |
| Recyclable/compostable | Can settle in transit |
| Easy to use | More material needed |
Specifications:
- Protection level: Light to moderate
- Cost: $0.05-0.15 per package
- Best use: Wrapping, light void fill
Packing Peanuts
Best for: conforming around irregular shapes
| Pros | Cons |
|---|---|
| Good cushioning | Customer dislike |
| Conforms to shapes | Messy |
| Reusable | Environmental concerns |
| Moderate cost | Can shift in transit |
Specifications:
- Protection level: Moderate
- Cost: $0.10-0.25 per package
- Best use: Irregular shapes, multiple items
Bubble Wrap
Best for: wrapping fragile items directly
| Pros | Cons |
|---|---|
| Good cushioning | Adds bulk |
| Clear visibility | Environmental concerns |
| Reusable | Higher cost |
| Product wrapping | Not ideal for void fill |
Specifications:
- Protection level: Good
- Cost: $0.15-0.40 per package
- Best use: Direct product wrapping, not void fill
Foam Packaging
Best for: high-value/fragile items
| Pros | Cons |
|---|---|
| Excellent cushioning | Higher cost |
| Consistent protection | Not sustainable |
| Custom options available | Adds weight |
| Professional appearance | Inventory complexity |
Specifications:
- Protection level: Excellent
- Cost: $0.50-3.00 per package
- Best use: Electronics, glassware, precision items
Custom Inserts
Best for: high-volume, consistent products
| Pros | Cons |
|---|---|
| Perfect fit | Setup costs |
| Minimal waste | MOQ requirements |
| Fast packing | One SKU only |
| Brand experience | Inventory space |
Specifications:
- Protection level: Optimized
- Cost: $0.25-2.00 per unit (volume dependent)
- Best use: 500+ units of same product
Calculating Void Fill Quantity
The Volume Method
Step-by-step calculation:
| Step | Formula |
|---|---|
| 1 | Calculate box internal volume: L × W × H |
| 2 | Calculate product volume (including packaging) |
| 3 | Void = Box volume - Product volume |
| 4 | Target fill: 70-85% of void |
Example:
- Box internal: 12" × 10" × 8" = 960 in³
- Product: 8" × 6" × 4" = 192 in³
- Void: 960 - 192 = 768 in³
- Target fill: 768 × 0.75 = 576 in³ of void fill
The 2-Inch Rule
Simpler approach for fragile items:
| Fragility | Minimum Clearance |
|---|---|
| Non-fragile | 0.5-1" all sides |
| Moderate | 1-1.5" all sides |
| Fragile | 2" all sides |
| Very fragile | 2.5-3" all sides |
Calculate: Product dimensions + (clearance × 2) = minimum box dimensions
Material-Specific Quantities
How much material for common box sizes:
| Box Size | Air Pillows | Kraft Paper | Foam |
|---|---|---|---|
| 8×6×4" | 2-4 small | 2-3 sheets | 1 set corners |
| 12×10×6" | 4-8 medium | 4-6 sheets | 2" sheets |
| 16×12×8" | 8-12 medium | 8-12 sheets | Custom cut |
| 20×16×12" | 12-20 large | 12-18 sheets | Custom fit |
Void Fill Placement
The Blocking Principle
Product should not move:
| Test | Pass Criteria |
|---|---|
| Shake test | No movement felt |
| Invert test | Product doesn't shift |
| Drop test | Product stays centered |
Placement Strategy
Layer method:
| Layer | Purpose |
|---|---|
| Bottom | Cushion against drops |
| Sides | Block lateral movement |
| Top | Protect from impacts |
| Corners | Highest impact zones |
Common Mistakes
| Mistake | Problem | Solution |
|---|---|---|
| Loose fill only | Product settles to bottom | Fill bottom first, pack around |
| Fill on top only | No bottom cushion | Distribute evenly |
| Overstuffed | Box bulges, damages | Use less fill, right-size box |
| Gaps at corners | Impact damage | Focus fill on corners |
Right-Sizing Before Void Fill
The Priority Order
Optimization sequence:
| Priority | Action | Impact |
|---|---|---|
| 1 | Right-size box | Reduces void to fill |
| 2 | Select appropriate material | Optimizes protection |
| 3 | Use correct quantity | Minimizes waste |
| 4 | Place correctly | Maximizes effectiveness |
Box-Product Fit Guidelines
Optimal fit ratios:
| Box Volume vs Product Volume | Assessment |
|---|---|
| <125% | Too tight, no protection |
| 125-150% | Ideal for rigid products |
| 150-175% | Ideal for fragile products |
| 175-200% | Acceptable, more void fill needed |
| >200% | Box too large, right-size |
When to Add Box Sizes
Signs you need more box options:
| Indicator | Threshold |
|---|---|
| Average void fill cost | >$0.30/package |
| Void fill as % of box volume | >30% |
| Damage rate | >2% |
| Customer complaints about packaging | Increasing |
Cost Analysis
Material Cost Comparison
Per-package costs by protection level:
| Protection Level | Material | Cost Range |
|---|---|---|
| Light | Kraft paper | $0.05-0.15 |
| Moderate | Air pillows | $0.08-0.20 |
| Good | Air pillows + paper | $0.15-0.35 |
| Excellent | Foam | $0.50-2.00 |
| Premium | Custom insert | $0.75-3.00 |
Total Cost of Void Fill
Include all factors:
| Cost Component | How to Calculate |
|---|---|
| Material cost | Price × quantity |
| Labor cost | Time × hourly rate |
| DIM weight impact | Added inches × rate |
| Storage cost | Inventory holding |
| Damage offset | Claims avoided |
ROI of Better Void Fill Strategy
Example calculation:
| Scenario | Current | Optimized |
|---|---|---|
| Void fill cost | $0.45 | $0.25 |
| Box size impact | +$1.20 (DIM) | +$0.40 |
| Damage rate | 2.5% | 1.5% |
| Damage cost/order | $1.25 | $0.75 |
| **Total/package** | **$2.90** | **$1.40** |
| **Monthly savings (1,000 orders)** | - | **$1,500** |
Sustainable Void Fill Options
Environmental Considerations
| Material | Recyclability | Biodegradability | Customer Perception |
|---|---|---|---|
| Air pillows | Varies | No | Neutral |
| Kraft paper | Yes | Yes | Positive |
| Biodegradable peanuts | Compostable | Yes | Positive |
| Recycled foam | Limited | No | Neutral |
| Custom paper inserts | Yes | Yes | Positive |
Sustainable Material Costs
| Material | Cost Premium | ROI Opportunity |
|---|---|---|
| Recycled content air pillows | +10-20% | Brand perception |
| Kraft paper (FSC certified) | +5-15% | Sustainability message |
| Cornstarch peanuts | +30-50% | Compostable claim |
| Mushroom packaging | +50-100% | Premium positioning |
Testing Void Fill Effectiveness
Drop Test Protocol
ISTA-style testing:
| Test | Method |
|---|---|
| Flat drop | 30" drop onto each face |
| Corner drop | 24" drop onto each corner |
| Edge drop | 24" drop onto each edge |
| Repeat | 3x each position |
Pass criteria: No product damage, product stays centered
Vibration Testing
Simulating transit:
| Method | Duration |
|---|---|
| Shake table | 30-60 minutes |
| Hand shake | 2 minutes continuous |
| Re-inspect | Check for settling, damage |
Climate Testing
For temperature-sensitive products:
| Test | Conditions |
|---|---|
| Heat | 8 hours at 100°F |
| Cold | 8 hours at 32°F |
| Humidity | 8 hours at 85% RH |
Automation and Efficiency
Manual vs Automated
| Volume | Recommendation |
|---|---|
| <100/day | Manual, pre-measured quantities |
| 100-500/day | Semi-automated (inflator, dispenser) |
| 500+/day | Fully automated systems |
Equipment ROI
| Equipment | Cost | Break-even Volume |
|---|---|---|
| Air pillow inflator | $500-2,000 | 200/day |
| Paper dispenser | $200-800 | 100/day |
| On-demand packaging | $10,000-50,000 | 500+/day |
| Custom insert machinery | $50,000+ | High volume, single SKU |
Frequently Asked Questions
How much void fill is too much?
If void fill exceeds 30% of box volume, your box is too large. Right-size the box first, then fill remaining void. Excessive void fill increases costs through materials, DIM weight, and labor.
Which is better: air pillows or paper?
Air pillows for general void fill (lightweight, cost-effective). Paper for sustainability messaging and lighter products. For fragile items, foam or custom inserts provide better protection than either.
Should I eliminate void fill entirely?
No—some cushioning is always needed. The goal is minimum void fill, not zero. Even perfectly right-sized boxes need protection at corners and between product and walls.
How do I reduce void fill costs?
Priority order: (1) Right-size boxes to reduce void, (2) Negotiate bulk material pricing, (3) Train packers on proper quantities, (4) Consider automation at volume. Cutting material quality to save money often increases damage costs more than savings.
Do customers care about void fill?
Yes. 72% of consumers dislike excessive packaging. Oversized boxes with too much fill signal waste. Right-sized packages with appropriate fill appear thoughtful and professional.
What void fill works for multi-item orders?
Tissue paper or kraft paper for wrapping individual items, then air pillows or paper to fill remaining void. The challenge is preventing items from damaging each other during transit.
Sources & References
- [1]Protective Packaging Best Practices - Packaging Digest (2024)
- [2]E-commerce Packaging Standards - ISTA (2024)
- [3]Void Fill Material Guide - Uline (2025)
- [4]Consumer Packaging Preferences - Shopify (2024)
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