Free parcel DIM calculator · UPS, FedEx & USPS
Dimensional weight calculator
Use this free dimensional weight calculator — also known as a volumetric weight calculator — to see what UPS, FedEx, or USPS will bill for a parcel. It prices the space a package takes, not just its scale weight. Enter the measured sides and actual weight; the calculator rounds each side up, applies the carrier divisor, and shows the billable weight plus the density where actual weight starts winning.
- UPS, FedEx, and USPS
- Whole-inch round-up
- USPS 2026 rules
- No signup or uploads
Package details
One parcel at a time. Results update as you type.
Units & conversion
Auto-converts when you switch.
Package size
Presets are standard US box sizes in inches.Non-rectangular applies only to USPS, which multiplies the cube by 0.785. UPS and FedEx use the rectangular bounding box.
Enter dimensions and actual weight to get started.
Quick answer
A 24 × 18 × 16 in parcel at 15 lb is 6,912 in³ (4.00 ft³). At UPS Daily divisor 139, DIM weight is 50 lb — 35 lb above actual — so 50 lb bills. At UPS Retail divisor 166, the same parcel is 42 lb.
The method
How shipping dimensional weight is calculated
Dimensional weight is not the parcel’s physical volume divided by a number. Each measured side is rounded up to the next whole inch before the cube is calculated. That step alone can add pounds to a light parcel.
This shipping dimensional weight calculator uses the same steps as the carriers. UPS and FedEx have used whole-inch round-up since August 18, 2025. USPS uses the same round-up in its current dimensional-weight steps. The calculator keeps the measured and rounded dimensions separate so the change is visible.
Worked example · UPS Daily
Measured24 × 18 × 16 in
Rounded up24 × 18 × 16 in
Cube6,912 in³ · 4.00 ft³
DIM weight6,912 in³ ÷ 139 = 50 lb
Actual weight15 lb
Billable50 lb
01 · Round each side
ceil(L), ceil(W), ceil(H)
12.1 in becomes 13 in. Do this before multiplying.
02 · Cube and divide
L × W × H ÷ divisor = DIM lb
Cube is in cubic inches. Round the DIM result up to the next whole pound.
03 · Bill the greater
max(actual lb, DIM lb) = billable lb
Then apply the carrier threshold, cap, and accessorials.
How to calculate dimensional weight for UPS
The UPS dimensional weight calculator mode above uses two divisors. UPS Daily Rates use 139; UPS Retail Rates use 166. Both round each side up before the cube is calculated.
- 01Measure each side and round up to the next whole inch.
- 02Multiply length × width × height to get cubic inches.
- 03Divide by 139 for Daily Rates or 166 for Retail Rates.
- 04Round the DIM result up to the next whole pound.
- 05Bill the greater of DIM weight and actual weight.
| Rate basis | Divisor | 6,912 in³ ÷ divisor | Billable at 15 lb |
|---|---|---|---|
| UPS Daily | 139 | 50 lb | 50 lb |
| UPS Retail | 166 | 42 lb | 42 lb |
Reference
UPS, FedEx, and USPS dimensional weight rules for 2026
These are the published US rules used by the calculator. Flat-rate packaging, carrier-owned packaging, and negotiated contracts can use different terms.
Reviewed
| Rate basis | Divisor | DIM starts | DIM cap | Shape factor |
|---|---|---|---|---|
UPS Daily 2026 Daily Rates Source | 139 | All parcel sizes | No DIM cap | Rectangular box |
UPS Retail 2026 Retail Rates Source | 166 | All parcel sizes | No DIM cap | Rectangular box |
FedEx 2026 list rates Source | 139 | All parcel sizes | No DIM cap | Rectangular box |
USPS July 12, 2026 Source | 139 | Above 1,728 in³ | 70 lb | 0.785 non-rectangular |
“All parcel sizes” means the published rule applies from the first cubic inch, subject to service exclusions such as flat-rate packaging. Contract customers should replace the divisor with the one on their agreement.
UPS · Daily vs Retail
139 / 166UPS dimensional weight calculator
The UPS dimensional weight calculator mode uses divisor 139 for Daily Rates and 166 for Retail Rates. The same 24 × 18 × 16 in parcel is 50 lb at Daily and 42 lb at Retail.
Whole-inch round-up since August 18, 2025. Contract tariffs can differ.
FedEx · Express & Ground
139FedEx dimensional weight calculator
The FedEx dimensional weight calculator mode uses divisor 139 for Express and Ground list rates. A 24 × 18 × 16 in parcel at 15 lb is 50 lb DIM, so 50 lb bills.
Whole-inch round-up since August 18, 2025. One Rate and contract tariffs can differ.
USPS · Priority & Ground Advantage
139USPS dimensional weight calculator
The USPS dimensional weight calculator mode applies divisor 139 only above 1,728 in³, caps DIM at 70 lb, and multiplies non-rectangular parcels by 0.785 before the divisor.
Priority Mail stops at 108 in length + girth; Ground Advantage can reach 130 in at the oversized price. USPS moved from 166 to 139 on July 12, 2026.
Actual vs DIM
Actual weight vs dimensional weight
Actual weight is the parcel on the scale. Dimensional weight is the space it occupies converted to pounds. The billable weight is the greater of the two, after carrier thresholds and caps.
The table below is the actual weight vs dimensional weight comparison the calculator runs on every parcel. DIM weight does not replace actual weight, and actual weight does not automatically win just because the parcel is heavy. The result panel also shows the uplift in pounds and the cube or height reduction that would flip the result.
USPS exception
USPS only compares actual and dimensional weight above 1,728 in³. Below that, the actual weight bills even if the parcel is light for its size.
| Parcel | Actual | DIM | Billable |
|---|---|---|---|
Dense 12 × 12 × 12 in · 20 lb actual | 20 lb | 13 lb Actual weight wins | 20 lb |
Typical 24 × 18 × 16 in · 15 lb actual | 15 lb | 50 lb DIM weight wins | 50 lb |
Bulky 24 × 24 × 24 in · 30 lb actual | 30 lb | 100 lb DIM weight wins | 100 lb |
USPS cap 30 × 20 × 18 in · 10 lb actual | 10 lb | 78 lb → 70 70 lb DIM cap | 70 lb |
UPS Daily divisor 139 except the USPS row. The USPS row shows the uncapped DIM result before the 70 lb cap.
Density break-even
Dimensional weight break-even density
Divide 1,728 by the carrier divisor to get the break-even density. A parcel below that density is billed on dimensional weight; a parcel above it is dense enough for actual weight to win.
At divisor 139, the break-even is 12.43 lb/ft³. The example parcel is only 3.75 lb/ft³, so DIM adds 35 lb. To make actual weight win at the same cube, it would need about 50 lb of payload.
The calculator’s reverse solver converts the required cube reduction into a height reduction, assuming all of the change comes from the parcel height. For the example, that is about 11.2 in off the height — useful when choosing a box, not a guarantee that the carrier will measure it that way.
Break-even by divisor
| Divisor | Break-even density | Typical use |
|---|---|---|
| 139 | 12.43 lb/ft³ | UPS Daily, FedEx, USPS |
| 166 | 10.41 lb/ft³ | UPS Retail |
| 200 | 8.64 lb/ft³ | Contract example |
| 250 | 6.91 lb/ft³ | Contract example |
A higher divisor is more forgiving: the parcel must be less dense before DIM weight exceeds actual weight.
Reference
Dimensional weight chart for common box sizes
Whole-inch dimensions, no contents. Use these as a sanity check, then enter the parcel’s actual measurements and weight in the calculator.
| Box | Cube | DIM weight at 139 | DIM weight at 166 | USPS DIM? |
|---|---|---|---|---|
| 12 × 9 × 6 in | 648 in³(0.38 ft³) | 5 lb | 4 lb | Not applied |
| 12 × 12 × 12 in | 1,728 in³(1 ft³) | 13 lb | 11 lb | Not applied |
| 16 × 12 × 8 in | 1,536 in³(0.89 ft³) | 12 lb | 10 lb | Not applied |
| 18 × 18 × 18 in | 5,832 in³(3.38 ft³) | 42 lb | 36 lb | Above threshold |
| 24 × 18 × 16 in | 6,912 in³(4 ft³) | 50 lb | 42 lb | Above threshold |
| 24 × 24 × 24 in | 13,824 in³(8 ft³) | 100 lb | 84 lb | Above threshold |
DIM weights are rounded up to the next whole pound. The USPS column tests the rectangular cube against the 1,728 in³ threshold; a non-rectangular parcel would use 0.785 of the cube.
Parcel or LTL?
Dimensional weight vs LTL freight class
Parcel carriers price the space a package takes through a divisor. LTL carriers price freight through freight class, density, and the NMFC item. The two systems can point in the same direction, but they are not interchangeable.
What is the LTL DIM factor for 2026?
There is no single LTL DIM factor. US LTL carriers price density — pounds per cubic foot — and map it to an NMFC freight class. The 13-tier density scale that took effect July 19, 2025 remains the basis for 2026. Some carriers add cubic-capacity or tariff-specific dim rules for low-density freight, so check the carrier’s rules tariff. For a pallet, use the freight class and density calculator, not a parcel divisor.
Is there an LTL dimensional weight calculator?
Not in the parcel sense. LTL uses density and freight class rather than a 139 or 166 divisor. Use the freight class and density calculator for pallets and the linear feet calculator for trailer floor space.
If the shipment is palletized, weighs more than a parcel network comfortably handles, or exceeds the general parcel limits, switch tools before you switch packaging.
Parcel DIM weight
- UPS, FedEx, USPS networks
- Divisor 139 or 166
- Whole-inch round-up
- USPS threshold and 70 lb cap
- Billable weight, not freight class
LTL freight class
- Pallets and handling units
- 2025 NMFC density scale
- Class 50 through 400
- NMFC item and commodity rules
- Density-based estimate, not a quote
Rules of thumb
Parcel. Individual boxes, usually under 150 lb, moving through a small-package network.
LTL. Palletized freight or multiple handling units that ship on a truck.
Limits. UPS and FedEx stop at 108 in on the longest side or 165 in length + girth.
Avoid the uplift
How to avoid dimensional weight charges
You cannot avoid DIM weight on every parcel. You can avoid paying for cube you do not need. These are the inputs to check before the label prints.
Right-size the box
Cut the height first. DIM weight scales with every inch, and a box that is 2 in too tall can add pounds without adding protection.
Remove void fill
Air does not add billable density. Pack the carton so the product fills the space, not the peanuts. If the box is mostly air, it is mostly DIM weight.
Measure the widest point
Bulges, labels, and stretch wrap count. Each side rounds up, so a 12.1 in side becomes 13 in before the cube is calculated.
Know the USPS threshold
At or below 1,728 in³, USPS does not apply DIM. A smaller box can avoid the comparison entirely; above it, the 70 lb cap limits the damage.
Compare 139 with 166
UPS Daily, FedEx, and USPS use 139. UPS Retail uses 166. The same 24 × 18 × 16 in parcel is 50 lb at Daily and 42 lb at Retail.
Audit reweighs and negotiate
Keep your measured dimensions and photos. Dispute obvious re-dim errors, and ask about the divisor if your volume supports a contract review.
DIM weight is not the price. Zone, service, fuel, additional handling, nonstandard fees, and contract discounts still determine the final charge. For the LTL side, read why freight class changes after pickup and the methodology and DIM sources.
FAQ
Dimensional weight calculator FAQ
The calculator uses the rounded dimensions in the receipt. If a carrier measures differently, the carrier’s scan usually controls. The freight-weight questions cover actual weight and density for dense items such as steel plate, which usually bill differently from parcel DIM weight.
What is dimensional weight?
Dimensional weight, also called volumetric weight or DIM weight, is a carrier’s way of pricing the space a parcel occupies rather than only its scale weight. The carrier multiplies the rounded parcel dimensions, divides by a published divisor, and compares the result with the actual weight. The higher number is the billable weight, subject to service caps and accessorial charges.
How to calculate dimensional weight?
Round each measured side up to the next whole inch. Multiply length × width × height to get cubic inches. Divide by the carrier divisor — 139 for UPS Daily, FedEx, and USPS, or 166 for UPS Retail — and round up to the next whole pound. The billable weight is the greater of that result and the actual weight.
What is the dimensional formula for weight?
In shipping, dimensional weight is (length × width × height) ÷ divisor. Use the rounded dimensions, keep the cube in cubic inches, and round the result up to the next pound. For example, 24 × 18 × 16 in = 6,912 in³; 6,912 ÷ 139 = 49.7, which rounds up to 50 lb. A different carrier divisor changes the result.
How to calculate kg from dimensions?
Multiply length × width × height in centimetres to get cm³. Air freight often uses 6,000 cm³ per kg, so divide the cube by 6,000 and round up; confirm the factor in the carrier’s tariff. For US parcel rates, calculate DIM pounds first: cubic inches ÷ 139 (or 166 for UPS Retail), then multiply by 0.4536 to convert to kilograms. The calculator’s cm/kg toggle handles the unit conversion.
How to identify the dimensions?
Measure the outside of the carton at its widest point, including bulges, labels, and stretch wrap. The longest side is length; the other two sides are width and height. Round each side up to the next whole inch before calculating DIM weight. For an irregular parcel, use the smallest rectangular box that encloses it; USPS also applies the 0.785 non-rectangular factor.
How do I calculate dimensional weight for UPS?
Measure each side and round up to the next whole inch, multiply length × width × height, then divide by 139 for UPS Daily Rates or 166 for UPS Retail Rates. Round the result up to the next whole pound. UPS bills the greater of that number and the actual weight.
How does FedEx calculate dimensional weight?
FedEx Express and Ground list rates use divisor 139. Round each measured side up to the next whole inch, multiply length × width × height, divide by 139, and round up to the next whole pound. FedEx has used whole-inch round-up since August 18, 2025. One Rate and contract tariffs can differ.
How to calculate dimensional weight for USPS?
Round each measured side up to the next whole inch, multiply length × width × height, and divide by 139. USPS applies DIM only above 1,728 in³, caps it at 70 lb, and multiplies non-rectangular parcels by 0.785 before the divisor. USPS moved from 166 to 139 on July 12, 2026.
What are the USPS size limits for DIM weight?
Priority Mail stops at 108 inches combined length and girth. USPS Ground Advantage can go to 130 inches at the oversized price, but a parcel over 130 inches is outside USPS parcel limits. Dimensional weight still applies above 1,728 cubic inches; the calculator flags a parcel that is over either size threshold.
What is the difference between dimensional weight and actual weight?
Actual weight is the parcel as tendered on the scale. Dimensional weight is the space it occupies converted to pounds. The billable weight is the greater of the two, after carrier thresholds and caps. A dense parcel can bill on actual weight; a light, bulky parcel usually bills on DIM weight.
Is this an actual weight vs dimensional weight calculator?
Yes. It calculates both actual and dimensional weight, then shows which one the carrier will bill. The result panel also shows the pound uplift and the height reduction that would make actual weight win at the same cube.
How to calculate 12 mm plate weight?
For carbon steel, use weight = length × width × thickness × 7,850 kg/m³, with all dimensions in metres. A 12 mm plate is 0.012 m thick, so one square metre weighs about 94.2 kg (19.3 lb/ft²). Multiply by the plate area for the total. This is actual weight, not dimensional weight; dense plate normally bills on actual weight, and LTL shipments should use the freight class and density calculator.
What is the weight of a 20mm plate?
A 20 mm carbon steel plate weighs about 157 kg per square metre (32.2 lb/ft²), because 0.020 m × 7,850 kg/m³ = 157 kg/m². The total depends on length and width: multiply the per-square-metre figure by the plate area. Stainless steel and aluminium use different densities, so substitute their density if needed. This is actual weight, not DIM weight.
Is there an LTL dimensional weight calculator?
Not in the parcel sense. LTL carriers use density and freight class rather than a 139 or 166 divisor. Use the freight class and density calculator for pallets and the linear feet calculator for trailer floor space.
How do I avoid dimensional weight charges?
You cannot avoid DIM weight on every parcel, but you can avoid paying for unnecessary cube. Right-size the box, cut the height before the length or width, remove void fill, and measure at the widest point because each side rounds up. Know the thresholds: USPS does not apply DIM at or below 1,728 in³, and its DIM is capped at 70 lb. Compare UPS Daily (139) with UPS Retail (166), audit reweighs, and negotiate the divisor if your volume supports it.
Why is my carrier invoice higher than this result?
This is an estimate of billable weight, not a price. Carriers can reweigh and re-dimension parcels, apply additional-handling or nonstandard fees, use a negotiated divisor, or rate a service with different rules. Fuel surcharges, zone, and accessorials are not included.
Sources
USPS dimensional-weight steps and size limits: DMM 123 (Priority Mail), DMM 201 (physical standards), and DMM 283 (Ground Advantage). UPS and FedEx divisors and whole-inch round-up: carrier dimensional-weight pages. By the FreightClassHub editorial team. Last updated . FreightClassHub is independent and not affiliated with UPS, FedEx, USPS, or the NMFTA.
Read the methodology and DIM sources. USPS check at divisor 139: 50 lb DIM for the example parcel.