How to Reduce DIM Weight Shipping Costs
DIM weight charges can significantly increase your shipping expenses. Here are proven strategies to minimize these costs without compromising product protection.
1. Right-Size Your Boxes
The single most effective way to reduce DIM weight is using the smallest possible box for each shipment. Many shippers default to a few standard box sizes, but this often leads to wasted space and higher charges.
How to Right-Size
- Measure your products: Know the exact dimensions of your top-selling items
- Add minimal padding: 1-2 inches on each side is typically sufficient
- Stock multiple box sizes: Having 5-8 sizes covers most scenarios
- Custom boxes: For high-volume products, custom sizing pays off
💡 Example Savings
Switching from a 16×12×8" box to a 12×10×6" box for the same product reduces DIM weight from 11 lbs to 5 lbs—a 54% reduction in billable weight.
2. Reduce Void Fill
Void fill (packing peanuts, air pillows, bubble wrap) adds volume without adding value to your DIM calculation. Minimizing empty space reduces your box size requirements.
Efficient Void Fill Options
| Method | Best For | Space Efficiency |
|---|---|---|
| Kraft paper | Light items | Excellent |
| Molded pulp | Electronics | Excellent |
| Inflatable air pillows | Fragile items | Good |
| Custom inserts | High-volume SKUs | Excellent |
| Packing peanuts | Avoid if possible | Poor |
3. Consider Multi-Piece Shipments
For orders with multiple items, shipping in separate smaller boxes may cost less than one large box—especially when DIM weight kicks in.
When to Split Shipments
- Combined DIM weight exceeds individual DIM weights significantly
- Items have very different size profiles
- Zone-based pricing allows cost optimization
- Items ship from different warehouses anyway
⚠️ Watch Out
Splitting shipments adds handling fees and potentially multiple delivery attempts. Always calculate total costs including surcharges before splitting.
4. Negotiate Your DIM Divisor
If you ship significant volume, carriers may offer a higher DIM divisor as part of your negotiated rate. This directly reduces DIM weight calculations.
Typical Negotiated Divisors
| Shipping Volume | Typical Divisor | Savings vs 139 |
|---|---|---|
| Standard (default) | 139 | — |
| Medium (100+ pkgs/month) | 166 | ~16% |
| High (500+ pkgs/month) | 194 | ~28% |
| Enterprise (1000+) | 200-250 | 30-44% |
5. Choose the Right Carrier
Different carriers may be more cost-effective depending on your package profile:
- Small, light packages: USPS First Class (no DIM weight under 1 lb)
- Medium packages: Compare UPS, FedEx, and regional carriers
- Heavy packages: Actual weight often wins—focus on zone pricing
- Lightweight bulky: Negotiate DIM divisor or use poly mailers
6. Use Poly Mailers When Possible
For soft goods (clothing, textiles, non-fragile items), poly mailers dramatically reduce dimensions compared to boxes.
Poly Mailer Benefits
- Compressible—dimensions are measured at smallest point
- Lighter than cardboard
- Often exempt from DIM weight at lower thresholds
- Lower material cost
7. Audit Your Invoices
Carrier billing errors are common. Regularly audit invoices for:
- Incorrect dimension measurements
- Wrong DIM divisor applied
- Overcharges on void shipments
- Duplicate billing
Many shippers recover 2-5% of shipping costs through invoice auditing.
Calculate Your DIM Weight
Use our free calculator to compare DIM weight across different box sizes and carriers: