Shipping economics
USPS Shipping Cost Calculator
Letters price by ounce; packages price by billable weight (the higher of actual or DIM weight) and zone. This model uses 2026 example retail rates you can edit to match your exact shipment.
What does this tool do?
USPS Shipping Cost Calculator computes the result directly in your browser — Letters price by ounce; packages price by billable weight (the higher of actual or DIM weight) and zone. This model uses 2026 example retail rates you can edit to match your exact shipment. Nothing you enter is uploaded or stored.
Reviewed by BoringToolsKit · September 1, 2026 · Example rates, editable — not carrier quotes.
How the estimate works
Package postage ≈ service base rate for billable weight × zone multiplier + fuel surcharge % + extras. Billable weight is the higher of actual weight (rounded up to the next pound) or dimensional weight = L × W × H (inches) ÷ 166. Flat Rate boxes skip DIM entirely.
Calculator
Estimated cost
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Rate tables below are editable example defaults for modeling, not carrier quotes. Actual prices vary by negotiated rates, surcharges, and season. Confirm final cost with the carrier before shipping.
2026 example rates (Priority vs Ground Advantage)
| Billable weight | Zone 1-2 | Zone 3-4 | Zone 5-6 | Zone 7-9 |
|---|---|---|---|---|
| 1 lb | $9.25 | $9.70 | $10.15 | $10.60 |
| 5 lb | $11.50 | $12.20 | $13.54 | $15.30 |
| 10 lb | $14.30 | $15.80 | $17.90 | $20.80 |
| 20 lb | $19.90 | $22.40 | $25.90 | $30.60 |
Example retail rates for modeling (vintage 2026); confirm on usps.com. Flat Rate boxes: Small $10.40, Medium $18.90, Large $25.20 (example).
Formula and assumptions
Total ≈ base rate (billable weight row) × zone multiplier (1.0-1.45) × (1 + fuel %) + extras. Letters: $0.82 first ounce + $0.29 each additional ounce to 3.5 oz; postcards $0.65. DIM weight = L×W×H ÷ 166 (USPS divisor). Edit any rate to match your label price.
USPS Shipping Cost Calculator questions
How does USPS calculate billable weight?
Packages are billed at the higher of actual weight (rounded up to the next pound) or dimensional weight: length × width × height in inches divided by 166. Flat Rate boxes are exempt from DIM pricing.
What are the 2026 USPS letter rates?
Example retail: First-Class letter $0.82 for the first ounce, +$0.29 per added ounce up to 3.5 oz; postcards $0.65. Rates change mid-year — verify current prices on usps.com.
Does zone affect Priority Mail cost?
Yes — farther zones cost more at the same weight. The zone multiplier in this model ranges from 1.0 (zones 1-2) to about 1.45 (zones 7-9) as an editable estimate.
Is this an official USPS quote?
No. It is a modeling tool with editable example rates. Always confirm the label price on usps.com before shipping.