DimWeight Calc › Rule sources
Dimensional weight rules and official sources
All rules below were last checked on . Where a source is missing or unclear, the calculator turns the value into a setting you can change instead of guessing.
Carrier presets
UPS Daily Rates (domestic & international)
| Formula | L × W × H (in) ÷ 139 = lb |
|---|---|
| Rounding | Each side rounded up to a whole inch (min 1 in); dimensional and actual weight rounded up to the next whole lb. |
| Applies to | Dimensional weight “may apply to all UPS domestic and international package services”; billable weight = greater of actual and dimensional weight. |
| Effective | 2026 Daily Rates guide marked “Updated September 7, 2026”; the date the guide took effect could not be verified. |
- UPS pages disagree: U1 says “round up … 1.01 to 1.99 will be rounded up to 2” but also “rounding each measurement to the nearest whole number”; the 2026 Daily Rates guide says “1.1 will be considered 2”. Default: round up (research notes 1.2 #1). You can switch to nearest.
Not verified: UPS 2026 guide start date; UPS PDF text was read only as a search snippet (download blocked). Treat these as adjustable settings.
Sources (checked ):
- 2026 UPS Rate & Service Guide – Daily Rates (updated Sep 7, 2026; read as a search snippet, PDF download blocked – entry page linked) [U2, official, search snippet only]
- UPS – Shipping dimensions and weight [U1, official]
UPS Retail Rates – domestic
| Formula | L × W × H (in) ÷ 166 = lb |
|---|---|
| Rounding | Same as Daily Rates: sides rounded up (min 1 in), weight rounded up to whole lb. |
| Applies to | Retail (counter / list) rates for US domestic packages. |
| Effective | Not verified. |
- U1: “139 for Daily Rates; 166 for Retail Rates”.
- UPS pages disagree: U1 says “round up … 1.01 to 1.99 will be rounded up to 2” but also “rounding each measurement to the nearest whole number”; the 2026 Daily Rates guide says “1.1 will be considered 2”. Default: round up (research notes 1.2 #1). You can switch to nearest.
Not verified: Effective date. Treat these as adjustable settings.
Sources (checked ):
- UPS – Shipping dimensions and weight [U1, official]
- 2026 UPS Rate & Service Guide – Retail Rates (search snippet, PDF download blocked – entry page linked) [U3, official, search snippet only]
UPS Retail Rates – export
| Formula | L × W × H (in) ÷ 139 = lb |
|---|---|
| Rounding | Sides rounded up (min 1 in), weight rounded up to whole lb. |
| Applies to | Retail rates for export packages. |
| Effective | Not verified. |
- Retail guide snippet: domestic 166, export 139.
- UPS pages disagree: U1 says “round up … 1.01 to 1.99 will be rounded up to 2” but also “rounding each measurement to the nearest whole number”; the 2026 Daily Rates guide says “1.1 will be considered 2”. Default: round up (research notes 1.2 #1). You can switch to nearest.
Not verified: Effective date. Treat these as adjustable settings.
Sources (checked ):
- 2026 UPS Rate & Service Guide – Retail Rates (search snippet, PDF download blocked – entry page linked) [U3, official, search snippet only]
- boxvolumecalculator.com – DIM weight rule changes [T1, third-party]
FedEx Express, Ground, Home Delivery & international (US Service Guide)
| Formula | L × W × H (in) ÷ 139 = lb |
|---|---|
| Rounding | Any fraction of an inch rounded up to the next whole inch; any fraction of a pound rounded up to the next pound. Billed on “the greater of the package’s actual rounded weight or dimensional weight”. |
| Applies to | All customer packaging; FedEx packaging “may” apply. US, international and US–Puerto Rico per package or per shipment; Ground and Home Delivery per package. |
| Effective | Service Guide 2026 effective Jan 5, 2026 (updated Sep 11, 2026); rounding each side up to the next inch effective Aug 18, 2025. |
- FedEx’s explainer page (F2) still says “nearest whole inch”; the Service Guide 2026 (F1, footnote 4) says any fraction of an inch is rounded up to the next whole inch, effective Aug 18, 2025. Default: Service Guide (research notes 1.2 #2). You can switch to nearest.
- FedEx Express can bill per shipment (total volume ÷ 139), which can differ by 1 lb from per-piece. Default: per piece.
Sources (checked ):
FedEx International Deferred Freight
| Formula | L × W × H (in) ÷ 166 = lb |
|---|---|
| Rounding | Same as other FedEx services. |
| Applies to | Only FedEx International Deferred Freight. |
| Effective | Service Guide 2026 (effective Jan 5, 2026). |
- Service Guide p.135 footnote 3.
- FedEx’s explainer page (F2) still says “nearest whole inch”; the Service Guide 2026 (F1, footnote 4) says any fraction of an inch is rounded up to the next whole inch, effective Aug 18, 2025. Default: Service Guide (research notes 1.2 #2). You can switch to nearest.
Sources (checked ):
USPS Priority Mail Express, Priority Mail, Ground Advantage, Parcel Select (retail & commercial) – from Jul 12, 2026
| Formula | If L × W × H (in) [× 0.785 if non-rectangular] > 1,728: ÷ 139 = lb |
|---|---|
| Rounding | Each side rounded up to the nearest whole inch (DMM 604.7.0); dimensional weight rounded up to the next whole lb. Above 70 lb the 70 lb price applies. |
| Applies to | Only parcels to Zones 1–9 whose volume exceeds 1 cubic foot (1,728 in³). Non-rectangular parcels: volume × 0.785 first. |
| Effective | From July 12, 2026 (DMM changes marked [7-12-26]; Postal Bulletin 22705). |
- Zones 1–9 only.
Sources (checked ):
- USPS DMM 123 – Priority Mail (retail) [P1, official]
- USPS DMM 113 – Priority Mail Express (retail) [P2, official]
- USPS DMM 213 – Priority Mail Express (commercial) [P2, official]
- USPS DMM 223 – Priority Mail (commercial) [P3, official]
- USPS DMM 253 – Parcel Select [P4, official]
- USPS DMM 283 – Ground Advantage (commercial) [P4, official]
- USPS Postal Bulletin 22705 [P5, official]
- USPS Ground Advantage [P6, official]
USPS Commercial Priority Mail – non-rectangular (DMM 223 text as published)
| Formula | L × W × H (in) × 0.785; if > 1,728: ÷ 166 = lb |
|---|---|
| Rounding | Each side rounded off (nearest whole inch); dimensional weight rounded up to the next whole lb. |
| Applies to | Commercial Priority Mail, non-rectangular parcels to Zones 1–9 over 1,728 in³ (after × 0.785). |
| Effective | Current DMM 223 text; this paragraph has no [7-12-26] mark. Whether USPS actually bills this way could not be verified. |
- DMM 223 still says ÷166 and “round off” for non-rectangular parcels, unlike the rectangular rule on the same page (139, round up) and the other DMM chapters. It may be an oversight by USPS; we follow the published text.
Not verified: Whether USPS applies 166 / round off in practice. Treat these as adjustable settings.
Sources (checked ):
- USPS DMM 223 – Priority Mail (commercial) [P3, official]
USPS – rule before Jul 12, 2026
| Formula | If L × W × H (in) [× 0.785] > 1,728: ÷ 166 = lb |
|---|---|
| Rounding | Each side rounded off to the nearest whole inch; dimensional weight rounded up to the next whole lb. |
| Applies to | Ship dates before July 12, 2026; Zones 1–9, over 1,728 in³. |
| Effective | Until July 11, 2026. |
Sources (checked ):
- USPS DMM 123 archive (rule before Jul 12, 2026) [P7, official]
- USPS QSG 150 archive (Jul 13, 2025 – old rule: ÷166) [P8, official]
DHL Express (cm / kg)
| Formula | L × W × H (cm) ÷ 5,000 = kg |
|---|---|
| Rounding | Dimensions: no official rounding found (not rounded). Weight: rounded up to the next 0.5 kg (DHL Express UK FAQ: “rounded up to the nearest half kilo”); other countries not verified. |
| Applies to | Per piece; billable weight = greater of actual and volumetric weight. DHL reserves the right to change it. |
| Effective | No effective date found. |
Not verified: 0.5 kg rounding outside the UK; Effective date; Dimension rounding. Treat these as adjustable settings.
Sources (checked ):
- DHL – Get a rate quote and transit time [D1, official]
- DHL Express – MyDHL / DCT help [D2, official]
- DHL Express UK – Measuring and weighing advice (per-piece rule) [D3, official]
- DHL Express UK FAQ – weight rounded up to the nearest half kilo [D4, official]
DHL Express (in / lb)
| Formula | L × W × H (in) ÷ 139 = lb |
|---|---|
| Rounding | Dimensions not rounded. Weight rounding in lb (whole lb or 0.5 lb) could not be verified – default whole lb, you can change it. |
| Applies to | Per piece; billable weight = greater of actual and volumetric weight. |
| Effective | No effective date found. |
Not verified: Weight rounding for in/lb shipments (whole lb? 0.5 lb?); Effective date. Treat these as adjustable settings.
Sources (checked ):
- DHL – Get a rate quote and transit time [D1, official]
- DHL Express – MyDHL / DCT help [D2, official]
DHL eCommerce US (in / lb)
| Formula | L × W × H (in) ÷ 166 = lb |
|---|---|
| Rounding | Not stated by DHL. Default: round to the nearest whole lb, because DHL’s own example writes 2,160 ÷ 166 = 13.01 as “13 lbs” (not rounding would show 13.01; rounding up would give 14). Round up is available as an option. Unverified – your DHL invoice is final. |
| Applies to | Per piece. Domestic pieces of 1 cubic foot (1,728 in³) or less are billed on actual weight. DHL Parcel / Parcel Plus: under 1 lb billed on actual weight; 1 lb or more and over 1 cubic foot, the greater of actual and dimensional. |
| Effective | No effective date found. |
- Default changed on 2026-10-29 from round up to round to nearest: the research table (§4.3) proposed round up as a placeholder, but DHL’s only published example [E1] (18 × 15 × 8 in = 2,160 ÷ 166 = 13.01 → “13 lbs”) is matched by rounding to the nearest whole lb. Not rounding gives 13.01 and rounding up gives 14, so neither matches it. One example cannot prove the rule (13.01 rounded down would also give 13), so this stays unverified.
Not verified: Dimension and weight rounding; Effective date. Treat these as adjustable settings.
Sources (checked ):
- DHL eCommerce US – Chargeable weight [E1, official]
- DHL eCommerce US – Parcel / Parcel Plus (PDF) [E2, official]
DHL eCommerce US (cm / kg)
| Formula | L × W × H (cm) ÷ 6,000 = kg |
|---|---|
| Rounding | Not stated by DHL – not rounded by default; choose a rounding if your bill shows one. |
| Applies to | Per piece; same 1 cubic foot domestic threshold as the inch rule. |
| Effective | No effective date found. |
Not verified: Dimension and weight rounding; Effective date. Treat these as adjustable settings.
Sources (checked ):
- DHL eCommerce US – Chargeable weight [E1, official]
Not verified (adjustable or not used)
- UPS official PDFs could not be downloaded; Daily/Retail guide wording comes from search snippets. The UPS 2026 guide start date is not verified.
- UPS US metric divisor (5,000) was only seen in a UPS Jamaica guide snippet – not used as a preset.
- DHL Express in/lb weight rounding (whole lb or 0.5 lb) – not found; user-selectable.
- DHL Express 0.5 kg rounding is only confirmed by DHL Express UK – user-selectable.
- DHL eCommerce dimension and weight rounding – not stated. Default: round to nearest whole lb (matches DHL’s own 13.01 → “13 lbs” example); round up and no rounding are selectable.
- DHL Express and DHL eCommerce effective dates – not found.
- USPS DMM 223 non-rectangular text (166 / round off) – unclear whether USPS applies it in practice.
- FedEx metric (5,000) – only the 2023 UK rate guide was read; not a preset.
- Sea LCL minimum charge and rounding – set by each forwarder; not applied.
- IATA TACT Rules original text (source of ÷6,000) – paid document, not read.
All sources
- UPS – Shipping dimensions and weight [U1, official]
- 2026 UPS Rate & Service Guide – Daily Rates (updated Sep 7, 2026; read as a search snippet, PDF download blocked – entry page linked) [U2, official, search snippet only]
- 2026 UPS Rate & Service Guide – Retail Rates (search snippet, PDF download blocked – entry page linked) [U3, official, search snippet only]
- UPS Jamaica Rate and Service Guide (search snippet only, not the US guide; no direct link verified) [U4, official, search snippet only; no verified link]
- FedEx Service Guide 2026, p.135–136 (effective Jan 5, 2026, updated Sep 11, 2026) [F1, official]
- FedEx US – What is dimensional weight? (still says “nearest whole inch”; conflicts with the Service Guide) [F2, official]
- FedEx UK rates (effective 2 January 2023 – older document) [F3, official]
- FedEx UK – How to calculate dimensional weight [F4, official]
- USPS DMM 123 – Priority Mail (retail) [P1, official]
- USPS DMM 113 – Priority Mail Express (retail) [P2, official]
- USPS DMM 213 – Priority Mail Express (commercial) [P2, official]
- USPS DMM 223 – Priority Mail (commercial) [P3, official]
- USPS DMM 253 – Parcel Select [P4, official]
- USPS DMM 283 – Ground Advantage (commercial) [P4, official]
- USPS Postal Bulletin 22705 [P5, official]
- USPS Ground Advantage [P6, official]
- USPS DMM 123 archive (rule before Jul 12, 2026) [P7, official]
- USPS QSG 150 archive (Jul 13, 2025 – old rule: ÷166) [P8, official]
- DHL – Get a rate quote and transit time [D1, official]
- DHL Express – MyDHL / DCT help [D2, official]
- DHL Express UK – Measuring and weighing advice (per-piece rule) [D3, official]
- DHL Express UK FAQ – weight rounded up to the nearest half kilo [D4, official]
- DHL eCommerce US – Chargeable weight [E1, official]
- DHL eCommerce US – Parcel / Parcel Plus (PDF) [E2, official]
- UN/CEFACT unit codes – A75 freight ton [C1, official]
- NVOCC Rules Tariff sample (LCL per CBM up to 1000 kg per CBM) [C2, third-party]
- Air China group – General Conditions of Cargo Carriage 1.21 (from Jan 1, 2025) [C3, official]
- IATA Knowledge Hub – Air cargo tariffs and rules [C4, official]
- boxvolumecalculator.com – DIM weight rule changes [T1, third-party]