Rate a shipment, or count what fits
Carriers charge for the weight your freight takes up, not just the weight it has. This calculator works out the volume, the dimensional weight under the published divisor rules, the density and estimated freight class, and the billable weight, then builds a cost from your own rate, because carrier rates are negotiated and no honest page can invent yours. A second mode counts how many pieces fit in a truck, container or room, testing every orientation.
Disclaimer: This calculator gives estimates for general information only. It is not financial, medical or other professional advice. Freight class here is the standard density based estimate; the official class of a shipment depends on its commodity under the carrier’s tariff, and final charges follow the carrier’s own measurement and terms.
What this calculator does
Shipping is priced on space as much as on weight, and the meeting point of the two ideas is billable weight: the greater of the actual weight and the dimensional weight, which is what your freight’s volume would weigh under the carrier’s divisor rule. This page works the whole chain from a tape measure: volume in cubic feet and CBM, density, the density based freight class used in US less-than-truckload shipping, dimensional weight under the standard published divisors, and the billable weight a carrier will actually rate. It then prices the shipment from a rate you supply, with the fuel surcharge and minimum charge handled the way a freight bill handles them. The fit mode answers the other everyday question, how many of these fit in that space, by testing all six orientations of the piece instead of assuming the first one you think of.
How to use it
- Measure the outside of the packed piece, pallet included, at its widest, longest and tallest points. Carriers measure the bulge, not the intention: a soft carton that bellies out is rated at the belly. Round up to the next inch or centimetre the way a carrier’s scanner will.
- Pick the divisor your service actually uses. 139 cubic inches per pound is the international parcel standard, 166 the gentler US domestic one; 5,000 cubic centimetres per kilogram is the air freight convention and 6,000 the common courier and road one. Using the wrong rule is the single most common reason an estimate and an invoice disagree.
- The rate field is yours because rates are negotiated. Two shippers on the same lane with the same freight pay different rates, so any page that quotes you a price without knowing your account is inventing it. Enter the per-pound or per-kilo rate from your tariff or quote and this page does the rest of the bill faithfully: freight, fuel surcharge on the freight, flat accessorials, and the minimum charge if the total falls below it.
- Freight class is a density estimate here. US LTL classes run from 50 (dense, cheap) to 500 (light and bulky, expensive). The density guide on this page is the standard published one, but the official class of a specific commodity is set by the National Motor Freight Classification and can differ; a carrier can also reclassify on inspection. Treat the class as a quoting estimate, which is what it is labelled.
- Fit mode is geometry, not a loading plan. It assumes identical rectangular pieces, all turned the same way, no pallets, wrapping or bracing, and no weight limit. Real loads lose space to all of those; treat the count as a ceiling.
How it is calculated
- Volume per piece = length x width x height. Total volume multiplies by the piece count, and is shown in cubic feet and CBM (1 CBM = 35.3147 cubic feet; 1 cubic foot = 1,728 cubic inches).
- Dimensional weight = volume / divisor, in the divisor’s own units, converted to your units when they differ (1 kg = 2.20462 lb).
- Billable weight = the greater of total actual weight and total dimensional weight.
- Density = total actual weight / total volume, shown in lb per cubic foot and kg per cubic metre (1 lb/ft3 = 16.0185 kg/m3).
- Freight class estimate reads density against the standard guide: below 1 lb/ft3 is class 500; 1 to 2 is 400; 2 to 3 is 300; 3 to 4 is 250; 4 to 5 is 200; 5 to 6 is 175; 6 to 7 is 150; 7 to 8 is 125; 8 to 9 is 110; 9 to 10.5 is 100; 10.5 to 12 is 92.5; 12 to 13.5 is 85; 13.5 to 15 is 77.5; 15 to 22.5 is 70; 22.5 to 30 is 65; 30 to 35 is 60; 35 to 50 is 55; 50 and above is class 50.
- Cost: freight charge = billable weight x your rate, rounded to cents; fuel surcharge = that freight charge x the surcharge percentage, rounded to cents; the estimated total = freight + fuel + accessorial fees, raised to the minimum charge if it falls below it.
- Fit count: for each of the six orientations of the piece, count = floor(space L / side 1) x floor(space W / side 2) x floor(space H / side 3); the best orientation is reported with the volume it uses.
Worked examples
The dimensional weight ambush. Four cartons, each 24 x 18 x 12 inches and 20 lb, shipping internationally (divisor 139). Each carton is 3.00 cubic feet; the shipment is 12.00 cubic feet (0.340 CBM). Dimensional weight per carton is 5,184 / 139 = 37.29 lb, so the shipment’s dimensional weight is 149.18 lb against an actual weight of only 80 lb. Billable weight: 149.18 lb. Density is 80 / 12 = 6.67 lb/ft3, estimated freight class 150. At a rate of $1.85 per billable pound the freight is $275.98; fuel at 20% adds $55.20; with $15 of accessorials the estimated total is $346.18. Nearly half of that bill is paying for air, which is precisely what dimensional pricing is designed to charge for.
Metric air freight. Two pieces at 60 x 40 x 40 cm, 12 kg each, divisor 5,000: volume 0.192 CBM in total, dimensional weight 19.20 kg per piece, 38.40 kg against 24 kg actual, so 38.40 kg is billed. Density is 125.0 kg/m3 (7.80 lb/ft3, class 125), and at $4.20 per kilo the freight is $161.28.
When actual weight wins, and the minimum bites. One dense crate, 12 x 12 x 12 inches, 30 lb, divisor 166: dimensional weight is only 10.41 lb, so the actual 30.00 lb is billed, density is 30.00 lb/ft3 and the class is a friendly 60. But at $2.00 a pound the freight is $60.00, and a $95 minimum charge lifts the bill to $95.00. Minimums are why small heavy shipments cost what they cost.
The fit test. A space 10 x 8 x 8 feet and pieces of 3 x 4 x 2 feet: lying the piece with its 3 ft side along the length, 4 ft side along the width and 2 ft side as the height fits 24 pieces, using 90.00% of the space. The first orientation most people try (4 ft along the length) fits only 16, which is why the page tests all six.
Reading your results
The most useful line is the one that says which weight won. If dimensional weight wins by a wide margin, the cheapest freight improvement available is packaging: a smaller carton, a vacuum bag, a product nested instead of boxed, directly cuts the billable weight without the product changing at all. Shippers who re-box a product one inch smaller on each side routinely cut a fifth of the freight bill, because volume falls with the cube of the packing.
If actual weight wins, the lever is the rate and the class, not the box. Check the density and class together: a class estimate that seems high for the goods usually means the density was dragged down by packaging or a pallet, and shipping the same goods denser (stacked, unpalletised where the carrier allows it) can move the class and the price with it.
And read the minimum charge line whenever it appears. A shipment at the minimum is a shipment whose size does not matter, which makes consolidation free: everything else that fits in the same bill costs nothing extra until the total climbs off the minimum.
Limitations
- Carrier rules vary in the details. Some carriers round each dimension up, some round weights up to the next pound or half kilo, some use different divisors for specific services, and oversize and length surcharges apply beyond thresholds that differ by carrier. This page uses the rules you select and plain arithmetic; the carrier’s tariff is the final word.
- The class estimate is density only. Official LTL classification also weighs stowability, handling and liability. Two shipments of identical density can carry different official classes, and a reclassification on inspection changes the bill.
- Ocean freight often prices by revenue ton (the greater of weight in tonnes and volume in CBM, the W/M rule) rather than by dimensional weight. The volume and weight figures here feed that comparison, but this page does not model ocean tariffs, port charges or container rates.
- Fit mode ignores real loading losses: pallet thickness, wrap, bracing, door clearance, weight limits and the rule that heavy pieces go on the floor. Expect a real load to land somewhat under the geometric count.
- Rates go stale. Fuel surcharges change monthly and tariffs annually. A rate from an old invoice prices the past faithfully and the present approximately.
Frequently asked questions
Why am I charged for 149 lb when my shipment weighs 80 lb?
Because the truck or plane sells space, and your four cartons occupy the space of 149 lb of average freight. Dimensional weight converts volume into the weight it displaces: at the international divisor of 139 cubic inches per pound, 12 cubic feet prices as 149.18 lb. The fix is never an argument with the carrier, it is a smaller box: billable weight falls with volume, so packaging is a pricing decision, not an afterthought.
Which divisor applies to my shipment?
The one in your carrier’s tariff for the service you bought. The widely published defaults are 139 for international parcel services, 166 for US domestic parcel, 5,000 for air freight and 6,000 for many courier and road services, all offered here as presets, plus a custom field for anything else. If an invoice surprises you, divide the volume on it by the billed dimensional weight: the answer is the divisor you were actually rated on, and it is worth knowing for every shipment after.
What does freight class actually change?
The rate per pound. Class is the LTL industry’s way of pricing density and difficulty: class 60 freight might move at a third of the per-pound price of class 200 freight on the same lane. That is why the density line matters commercially: a small density gain that crosses a class boundary (from 6.9 to 7.1 lb/ft3, say, moving 150 to 125) can cut the freight charge far more than the weight saving alone suggests.
Is CBM the same as cubic feet?
No: CBM is cubic metres, the unit international and ocean freight is quoted in, and one CBM is 35.3147 cubic feet. This page shows both, because domestic US shipping thinks in cubic feet and almost everyone else on earth thinks in CBM, and confusing them misprices a shipment by a factor of 35.
Related calculators
Method: dimensional weight by the published divisor rules named on the page; billable weight the greater of actual and dimensional; freight class from the standard density guide; costs built from the user’s own rate with fuel surcharge and minimum applied in bill order. Last reviewed: 13 October 2026.