USPS vs UPS vs FedEx: which is cheapest for your package?
Quick answer: as a rule of thumb, USPS is usually cheapest for small, light packages (under about 2 to 5 lb) and is the only carrier that delivers to PO boxes and APO/FPO military addresses. UPS and FedEx are often better value for heavy or bulky packages, offer more guaranteed delivery times, and have stronger business tools. Always compare quotes for your exact box, because size, weight, distance and discounts change the answer.
The three carriers at a glance
| USPS | UPS | FedEx | |
|---|---|---|---|
| Best for | Light packages, letters, flat rate boxes | Heavy and large packages, business shipping | Fast and overnight shipping, heavy packages |
| Main ground service | Ground Advantage | UPS Ground | FedEx Ground / Home Delivery |
| Main express services | Priority Mail, Priority Mail Express | Next Day Air, 2nd Day Air, 3 Day Select | Priority Overnight, 2Day, Express Saver |
| Delivers to PO boxes | Yes | No | No |
| Delivers to APO/FPO/DPO | Yes | No | No |
| Saturday delivery | Yes, included | Some services | Some services, Home Delivery on weekends |
| Money-back guarantee | Priority Mail Express only | Most air services | Most express services |
| Included insurance | Some services, up to $100 | Up to $100 declared value | Up to $100 declared value |
| Flat rate boxes | Yes | No (UPS Simple Rate is similar) | FedEx One Rate |
Why package size matters: dimensional weight
All three carriers can charge by dimensional (DIM) weight instead of actual weight when a box is large and light:
DIM weight = length x width x height (inches) ÷ divisor
UPS and FedEx commonly use a divisor of 139 for retail and daily rates. USPS applies dimensional pricing only to larger packages (over 1 cubic foot) and uses a higher divisor (166), which is one reason USPS is often cheaper for lightweight boxes.
Example: a 16 x 12 x 10 inch box weighing 5 lb has a DIM weight of about 14 lb at 139. You pay for 14 lb, not 5. Use the smallest box that protects the item.
Which carrier to choose
| You are shipping… | Usually cheapest or best |
|---|---|
| A document or small item under 1 lb | USPS Ground Advantage or First-Class |
| A heavy, dense item that fits a flat rate box | USPS Priority Mail Flat Rate |
| A 10-50 lb box going across the country | Compare UPS Ground and FedEx Ground |
| Something that must arrive tomorrow | UPS Next Day Air, FedEx overnight or Priority Mail Express |
| To a PO box or military address | USPS |
| High-value items needing detailed tracking | UPS or FedEx with declared value |
Ways to pay less with any carrier
- Buy labels online. Retail counter prices are usually higher than online prices.
- Use shipping software or marketplaces (such as online seller platforms) for discounted commercial rates.
- Weigh and measure accurately. See our pounds to kilograms and ounces to grams converters for international labels.
- Schedule free pickups instead of dropping off.
- Use regional carriers for short distances in some areas.
Shipping internationally
Customs forms, prohibited items and duties apply to every carrier. See how to ship a package internationally. For letters, see how much it costs to mail a letter.
Frequently asked questions
Is USPS cheaper than UPS? For small, light packages, usually yes. For heavy packages, UPS or FedEx Ground is often cheaper.
Which carrier is fastest? All three offer overnight services. For ground shipping, delivery times are similar and depend on distance.
Can UPS deliver to a PO box? No. Use USPS, or give UPS a street address.
Prices and services change often. Check each carrier’s website for current rates.