USPS Price Calculator
Estimate USPS postage based on weight, dimensions, service level, and destination zone. Combine accurate measurements with the current zone chart for the ZIP code you are shipping to.
How USPS Pricing Works
USPS pricing is driven by four core elements: the weight of the parcel, the cubic volume that converts to dimensional weight, the destination zone (1 through 9), and the service speed. First-Class Packages use ounce-based tiers up to one pound, while Priority Mail and Priority Mail Express bill by whichever is greater between the actual pounds and the dimensional weight calculated by dividing cubic inches by 166. Heavier or oversized parcels introduce handling surcharges once combined length and girth exceed 84 inches.
Every zone step away from the origin adds roughly four percent to retail postage, so comparing ZIP-code zones can save meaningful money. USPS also applies non-machinable surcharges to very small packets and oversize fees when the longest side surpasses 27 inches. Because of these rules, shippers should measure each dimension precisely and round up to the nearest whole ounce or pound when budgeting.
Tips for Using the Calculator
- Measure length, width, and height after packing materials are added to capture true cubic volume.
- Use the USPS zone chart tied to your origin ZIP to verify whether the destination is a nearby Zone 2 or a distant Zone 8 or 9.
- If you ship lightweight but bulky goods, compare dimensional and actual weight to avoid surprises.
- Flag parcels with combined length and girth above 84 inches so you can pre-plan for the large package surcharge.
Sample Calculations
Example 1: A 12 oz accessory in an 8 × 6 × 4 inch box headed to Zone 3 with First-Class Package service produces an estimated postage of about $5.70 after the ounce tiers and zone multiplier are applied.
Example 2: A 48 oz (3 lb) coffee shipment in a 12 × 8 × 6 inch carton going to Zone 6 via Priority Mail bills at the dimensional weight of 4 lb, triggering roughly $15.60 including a moderate zone multiplier.
Example 3: A 8 lb textile roll measuring 30 × 8 × 8 inches to Zone 8 via Priority Mail Express sees a high-speed base, a dimensional billable weight of 12 lb, and a large-package surcharge, yielding an estimate near $78.00.