Dimensional Weight Calculator

DIM weight = L × W × H ÷ 139 at UPS, FedEx and USPS (USPS only above 1,728 in³), with each side rounded up to the next inch and the result up to the next pound, so a 18.25 × 14.5 × 10.1 in box bills as 23 lb.

Billable weight · UPS 23 lb Billed on DIM weight · box billed as 19 × 15 × 11 in

DIM weight23 lb

Actual, rounded10 lb

Cube limit1,390 in³

Length (in)

Width (in)

Height (in)

Actual weight (lb)

Packages

Units

Custom divisor (in³ per lb)

Use packed outer dimensions. Metric inputs are converted to inches and pounds before carrier rounding.

This box is 1,745 in³ over the 1,390 in³ limit for 10 lb. Cut the billed cube to 1,390 in³ or less and it bills on actual weight.

Carrier	Billed size (in)	Cubic inches	DIM weight	Billable / package	All packages
UPS÷ 139	–	–	–	–	–
FedEx÷ 139	–	–	–	–	–
USPS÷ 139, over 1,728 in³	–	–	–	–	–
Custom÷ 166	–	–	–	–	–

Rules as each carrier publishes them, checked Oct. 2, 2026. Contract divisors and surcharges are not included.

The calculation runs in your browser.

Formula

How to Calculate Dimensional Weight in 4 Steps

Measure the packed box. Take the outside length, width and height in inches at the longest points, including bulges and handles.
Round each side up. Any fraction goes to the next whole inch, so 10.1 in counts as 11 in.
Multiply and divide. Multiply L × W × H for the cubic size, then divide by 139. At USPS, skip this step if the cube is 1,728 in³ or less.
Round up and compare. Round the result up to the next pound, round actual weight up too, and bill the greater of the two.

The worked figure. 18.25 × 14.5 × 10.1 in rounds to 19 × 15 × 11 in. That is 3,135 in³ ÷ 139 = 22.55, which rounds up to 23 lb. Actual weight 9.6 lb rounds to 10 lb, so the box bills at 23 lb.

Carrier rules

UPS, FedEx and USPS DIM Weight Rules Compared

Rule	UPS	FedEx	USPS
Divisor (in³ per lb)	139 (Daily Rates)	139 (U.S., Puerto Rico, international)	139
Each side	Fraction rounded up (1.1 in counts as 2 in); minimum 1 in	Not quoted here. The calculator rounds up, as UPS publishes; verify with your carrier	Rounded up to the next whole inch
DIM result	Up to the next whole pound	Not quoted here. The calculator rounds up, as UPS publishes; verify with your carrier	Up to the next whole pound
Actual weight	Up to the next whole pound	Not quoted here. The calculator rounds up, as UPS publishes; verify with your carrier	Any fraction of a pound counts as a whole pound
When DIM applies	May apply to all domestic and international packages	Every package	Over 1,728 in³ (1 cubic foot), Zones 1–9
Cap	None stated	None stated	DIM over 70 lb pays the 70 lb price
Published in	2026 UPS Rate and Service Guide, Daily Rates, updated Sept. 7, 2026	fedex.com (U.S. divisor 139), checked Oct. 2, 2026. Its rounding wording could not be quoted for this page	Domestic Mail Manual 223.1.4, 253.1.2, 283.1.4, revised July 12, 2026

Older pages disagree

Some carrier help pages still say "nearest whole inch". The current rate guides say round up. The calculator follows the round-up wording in the current guides.

USPS moved to 139

The USPS divisor was 166 before the July 12, 2026 revision. Calculators that still use 166 for USPS understate DIM weight on boxes over 1 cubic foot.

Contracts override

Negotiated agreements can set a different divisor or a DIM threshold. Enter it under Custom divisor to see what your own rate card bills.

Worked example

An Austin Candle Brand Shipping Gift Sets

A candle brand in Austin, Texas ships 40 gift sets a day in a 18.25 × 14.5 × 10.1 in box. Each packed set weighs 9.6 lb.

Step	UPS and FedEx	USPS
Billed size	19 × 15 × 11 in	19 × 15 × 11 in
Cubic inches	3,135	3,135 (over 1,728, so DIM applies)
DIM weight	3,135 ÷ 139 = 22.55 → 23 lb	23 lb
Actual weight	9.6 lb → 10 lb	10 lb
Billable per package	23 lb	23 lb
Billable for 40 packages	920 lb	920 lb

23 lbbillable per box at all three carriers

+13 lbover its rounded actual weight

1,390 in³largest cube that bills on 10 lb at UPS and FedEx

1,536 in³a 16 × 12 × 8 in box, if the set fits

In a 16 × 12 × 8 in box, the same set bills 12 lb at UPS and FedEx (11 lb less per box, 440 lb less a day).
At USPS that box is under 1,728 in³, so it bills on actual weight: 10 lb, or 13 lb less per box.
Rate cards price by zone and weight, so check each billable weight against your own rates before switching boxes.

DIM weight chart

DIM Weight of Common Box Sizes

Computed with the calculator's own rules. A box bills on its DIM weight whenever that is above its rounded actual weight.

Box (in)	Cubic inches	Cubic feet	UPS and FedEx (÷139)	USPS (÷139 over 1,728 in³)	At ÷166
6 × 6 × 6	216	0.13	2 lb	None	2 lb
8 × 6 × 4	192	0.11	2 lb	None	2 lb
10 × 8 × 6	480	0.28	4 lb	None	3 lb
12 × 9 × 6	648	0.38	5 lb	None	4 lb
11 × 11 × 11	1,331	0.77	10 lb	None	9 lb
12 × 12 × 8	1,152	0.67	9 lb	None	7 lb
12 × 12 × 12	1,728	1.00	13 lb	None	11 lb
14 × 10 × 10	1,400	0.81	11 lb	None	9 lb
16 × 12 × 8	1,536	0.89	12 lb	None	10 lb
16 × 12 × 12	2,304	1.33	17 lb	17 lb	14 lb
18 × 14 × 12	3,024	1.75	22 lb	22 lb	19 lb
20 × 16 × 12	3,840	2.22	28 lb	28 lb	24 lb
24 × 18 × 12	5,184	3.00	38 lb	38 lb	32 lb
24 × 18 × 18	7,776	4.50	56 lb	56 lb	47 lb

"None" means USPS bills the box on actual weight. ÷166 is shown as an example divisor for comparing a contract rate.

Rounding

What Rounding Each Side Up Adds

Carriers round every side before they multiply. The left columns use the exact tape measure; the right columns use the size the carrier bills.

Measured (in)	Exact in³	DIM on exact size	Billed size (in)	Billed in³	DIM billed	Added
12.1 × 9.1 × 6.1	671.7	5 lb	13 × 10 × 7	910	7 lb	+2 lb
11.5 × 8.5 × 4.25	415.4	3 lb	12 × 9 × 5	540	4 lb	+1 lb
18.25 × 14.5 × 10.1	2,672.7	20 lb	19 × 15 × 11	3,135	23 lb	+3 lb
20.2 × 16.1 × 12.1	3,935.2	29 lb	21 × 17 × 13	4,641	34 lb	+5 lb

Under the old nearest-inch rule the example box would have billed as 18 × 15 × 10 in and 20 lb. Rounding up adds 3 lb to that box. Measure to the next inch before you buy cartons.

USPS threshold

The USPS 1 Cubic Foot Line

USPS bills DIM weight only when the rounded cube exceeds 1,728 in³. Three 3 lb boxes show where the line falls.

11 × 11 × 11 in 1,331 in³

UPS and FedEx bill 10 lb. USPS bills 3 lb, because the cube is not over 1,728 in³.

12 × 12 × 12 in 1,728 in³

UPS and FedEx bill 13 lb. USPS bills 3 lb, because the cube is not over 1,728 in³.

12.1 × 12 × 12 in 1,872 in³

UPS and FedEx bill 14 lb. USPS bills 14 lb, because the rounded cube is over 1,728 in³.

A box of exactly 12 × 12 × 12 in is not over the line, so USPS bills it on actual weight.
A tenth of an inch more on one side rounds up to 13 in and pushes the cube to 1,872 in³.
Soft goods that fit a mailer under 1 cubic foot avoid USPS DIM weight entirely.

Lower DIM weight

The Largest Box That Still Bills on Actual Weight

For a given rounded weight, any billed cube at or under these limits bills on actual weight. The calculator shows yours above.

Rounded actual weight	UPS and FedEx max cube	UPS and FedEx cubic feet	USPS max cube
2 lb	278 in³	0.16	1,728 in³
5 lb	695 in³	0.40	1,728 in³
10 lb	1,390 in³	0.80	1,728 in³
15 lb	2,085 in³	1.21	2,085 in³
20 lb	2,780 in³	1.61	2,780 in³
30 lb	4,170 in³	2.41	4,170 in³

Stock fewer, tighter boxes

Pick a carton range around your best sellers so most orders ship with little void fill.

Use mailers for soft goods

Apparel and textiles often fit a poly mailer, which often takes up less space than a carton.

Trim the emptiest side

Every side is multiplied, so trimming the side with the most empty space often moves the cube under the limit.

Measure like the carrier

Measure at the bulge and round up before you quote, so the label weight matches the audit.

Which calculator

Dimensional, Volumetric or Chargeable Weight?

This page U.S. parcel DIM weight

UPS, FedEx and USPS in inches and pounds, with each carrier's rounding and the USPS threshold.

International Volumetric weight

Metric divisors such as 5,000 and 6,000 across air, express, road and sea. Use the volumetric weight calculator.

Freight Chargeable weight

Air cargo, express and sea LCL across several box sizes. Use the chargeable weight calculator.

Common mistakes

Six DIM Weight Mistakes That Change the Bill

Using product size, not box size

A 4 lb item measuring 14 × 10 × 8 in bills 9 lb. Add an inch of packaging per side, 16 × 12 × 10 in, and it bills 14 lb.

Not rounding each side

The example box is 2,672.7 in³ on the tape and 3,135 in³ on the invoice. Round every side up first.

Using 166 for USPS

USPS divides by 139 under the July 12, 2026 rules. At 166 the example box would show 19 lb, not 23 lb.

Assuming small boxes are safe

A 9 × 7 × 5 in box at 2 lb bills 3 lb at UPS and FedEx, though USPS bills it at 2 lb.

Comparing unrounded weights

A 9.6 lb box is rated at 10 lb. Compare rounded actual weight against rounded DIM weight, never raw figures.

Ignoring contract terms

Your agreement may set its own divisor or threshold. Enter it as a custom divisor before quoting customers.

Next step

Related Shipping and Packaging Calculators

Volumetric weight calculator Metric divisors (5,000, 6,000 and more) for air, sea, road and express in cm and kg. Chargeable weight calculator Air, express and sea LCL billing across several box sizes in one shipment. Box size calculator Find the smallest carton that fits your items and see the void it leaves. Freight class calculator Too big for parcel? Get density and the estimated LTL freight class.

See all free logistics tools, or read how Locad handles shipping and ecommerce fulfillment.

FAQ

Dimensional Weight Calculator Questions

Round each side of the packed box up to the next whole inch, multiply length × width × height, and divide by the carrier divisor. UPS, FedEx and USPS publish 139. Round the result up to the next pound. A 18.25 × 14.5 × 10.1 in box becomes 19 × 15 × 11 in, 3,135 cubic inches, and 23 lb.

USPS rounds each side up to the next whole inch. If the box is over 1,728 cubic inches (1 cubic foot), it divides by 139 and rounds up to the next pound, per the Domestic Mail Manual revised July 12, 2026. A dimensional weight over 70 lb pays the 70 lb price. Smaller boxes bill on actual weight.

FedEx divides length × width × height in inches by 139 for U.S. shipments and bills the greater of that figure and actual weight. Its pages differ on how fractional inches are rounded, so verify the rounding with your carrier. This calculator rounds FedEx up, as UPS publishes. Your account may carry a contract divisor.

The 2026 UPS Rate and Service Guide (Daily Rates, updated Sept. 7, 2026) rounds each fractional measurement up (1.1 in counts as 2 in), divides the cubic size by 139 and rounds up to the next pound. Actual weight also rounds up. The billable weight is the greater of the two.

The divisor, or DIM factor, is the number of cubic inches a carrier counts as one pound. UPS Daily Rates, FedEx U.S. and USPS all publish 139. A higher divisor means a lower DIM weight: the same 19 × 15 × 11 in box is 23 lb at 139 and 19 lb at 166. Contract rates can set their own.

Billable weight is the weight a carrier uses to look up your rate: the greater of rounded actual weight and dimensional weight. In the worked example a 9.6 lb box rounds to 10 lb, but its DIM weight is 23 lb, so it bills at 23 lb.

At UPS and FedEx it applies to every package, whatever its size. USPS applies it only above 1,728 cubic inches. A 11 × 11 × 11 in box at 3 lb bills 10 lb at UPS and FedEx but 3 lb at USPS.

Yes. Choose centimeters and kilograms and the calculator converts to inches and pounds before rounding, because U.S. carriers rate parcels in pounds. A 50 × 40 × 30 cm box at 8 kg bills as 20 × 16 × 12 in and 28 lb. For metric divisors such as 5,000, use the volumetric weight calculator.

They describe the same idea. Dimensional weight is the U.S. parcel term, in inches and pounds. Volumetric weight is the international term, usually in cm and kg. Chargeable weight is what air and sea freight bill: the greater of actual and volumetric weight.

Bring the billed cube down to the carrier's limit for your weight. At 139, a 9.6 lb box bills on actual weight up to 1,390 cubic inches. Use the smallest box that protects the item, measure to the next inch, and test mailers for soft goods.

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