Shipping Cost Estimator

Billable weight is the number that decides your shipping bill, and it is not what your scale says. Carriers charge on whichever is greater, the actual weight or the dimensional weight, so a light box that takes up a lot of room in the van is billed as though it were heavy.

This calculator works out that billable weight for you, then applies your own rate. It does not carry a rate table, because published parcel rates change every January and a number frozen in a web page is wrong within a year. Pull the base charge and the per-pound charge off your carrier’s rate card for your zone and service, or off a recent invoice, and type them in.

Dimensional weight: DIM weight (lb) = (Length × Width × Height in inches) ÷ DIM divisor

Those divisors are published carrier constants rather than prices, which is why they are safe to bake in. They change rarely, and when they do it makes trade-press headlines.

Billable weight = the greater of actual weight and DIM weight, rounded up

Worked example: A 12 × 10 × 8 inch box weighing 3 lb, going UPS Ground. DIM weight = (12 × 10 × 8) ÷ 139 = 960 ÷ 139 = 6.91 lb Billable weight = the greater of 3 and 6.91, rounded up = 7 lb

Say your rate card shows a $9.50 base and $1.20 a pound for that zone and service: Cost = $9.50 + (7 × $1.20) = $17.90, before fuel surcharge. Add a 16% fuel surcharge and it is $20.76.

Rough US domestic ranges, early 2025, to sanity-check what you type. These are list rates and move every year, so treat them as a smell test rather than a quote. A 1 lb parcel to a mid-distance zone runs about $9 to $16 depending on carrier and service; 5 lb runs about $16 to $25; ground service to an adjacent zone sits at the bottom of those, cross-country express well above them. Negotiated rates commonly land 20 to 40% under list, which is exactly why a calculator should ask you rather than guess.

Zones (US domestic): Zones 1 to 8 measure distance from the origin zip code, Zone 1 adjacent and Zone 8 cross-country. Your rate card has a column per zone, and the per-pound figure you type should come from the column matching your destination.

Fuel surcharge: a percentage the carriers reset weekly against diesel and jet fuel indices, applied on top of the base rate. It has spent recent years roughly in the 10 to 25% band. Check the current figure on your carrier’s site, because it is one of the few numbers that can move between quoting a customer and shipping the box.

One thing that dodges all of this: USPS Priority Mail flat-rate boxes ignore both weight and zone. If it fits and it is heavy for its size, the flat rate usually beats anything you will compute here.