# Unit of Measure Conversion Reference for ERP

> Source: https://netray.co/tools/unit-of-measure-conversion-reference
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

Searchable table of common UoM conversion factors for ERP item masters, with exact definitions where they exist.

## Category

erp-operations

## Audience

- ERP administrator
- Materials planner
- Buyer
- Data steward

## Tool

**Kind:** worksheet

**Mode:** reference

**Columns:**

#### From

**Key:** from_uom

**Type:** text

#### To

**Key:** to_uom

**Type:** text

#### Multiply by

**Key:** factor

**Type:** number

#### Dimension

**Key:** type

**Type:** text

#### Note

**Key:** note

**Type:** text

**Rows:**

**From uom:** in

**To uom:** mm

**Factor:** 25.4

**Type:** Length

**Note:** Exact by definition

**From uom:** ft

**To uom:** m

**Factor:** 0.3048

**Type:** Length

**Note:** Exact by definition

**From uom:** yd

**To uom:** m

**Factor:** 0.9144

**Type:** Length

**Note:** Exact by definition

**From uom:** mile

**To uom:** km

**Factor:** 1.609344

**Type:** Length

**Note:** Exact by definition

**From uom:** mil (thou)

**To uom:** mm

**Factor:** 0.0254

**Type:** Length

**Note:** 1 mil = 0.001 in

**From uom:** ft

**To uom:** in

**Factor:** 12

**Type:** Length

**Note:** Exact

**From uom:** m

**To uom:** mm

**Factor:** 1000

**Type:** Length

**Note:** Exact

**From uom:** cm

**To uom:** mm

**Factor:** 10

**Type:** Length

**Note:** Exact

**From uom:** lb

**To uom:** kg

**Factor:** 0.45359237

**Type:** Mass

**Note:** Exact by definition (avoirdupois)

**From uom:** oz

**To uom:** g

**Factor:** 28.349523125

**Type:** Mass

**Note:** Avoirdupois ounce, exact

**From uom:** lb

**To uom:** oz

**Factor:** 16

**Type:** Mass

**Note:** Exact

**From uom:** kg

**To uom:** g

**Factor:** 1000

**Type:** Mass

**Note:** Exact

**From uom:** metric ton (t)

**To uom:** kg

**Factor:** 1000

**Type:** Mass

**Note:** Exact

**From uom:** short ton (US)

**To uom:** kg

**Factor:** 907.18474

**Type:** Mass

**Note:** 2,000 lb

**From uom:** long ton (UK)

**To uom:** kg

**Factor:** 1016.0469088

**Type:** Mass

**Note:** 2,240 lb

**From uom:** troy oz

**To uom:** g

**Factor:** 31.1034768

**Type:** Mass

**Note:** Precious metals

**From uom:** L

**To uom:** mL

**Factor:** 1000

**Type:** Volume

**Note:** Exact

**From uom:** m3

**To uom:** L

**Factor:** 1000

**Type:** Volume

**Note:** Exact

**From uom:** gal (US)

**To uom:** L

**Factor:** 3.785411784

**Type:** Volume

**Note:** Exact by definition

**From uom:** gal (imperial)

**To uom:** L

**Factor:** 4.54609

**Type:** Volume

**Note:** Exact by definition

**From uom:** qt (US)

**To uom:** L

**Factor:** 0.946352946

**Type:** Volume

**Note:** 1/4 US gallon

**From uom:** gal (US)

**To uom:** qt (US)

**Factor:** 4

**Type:** Volume

**Note:** Exact

**From uom:** fl oz (US)

**To uom:** mL

**Factor:** 29.5735295625

**Type:** Volume

**Note:** 1/128 US gallon

**From uom:** ft3

**To uom:** L

**Factor:** 28.316846592

**Type:** Volume

**Note:** Exact from ft definition

**From uom:** barrel (oil)

**To uom:** L

**Factor:** 158.987294928

**Type:** Volume

**Note:** 42 US gallons

**From uom:** in2

**To uom:** mm2

**Factor:** 645.16

**Type:** Area

**Note:** Exact

**From uom:** ft2

**To uom:** m2

**Factor:** 0.09290304

**Type:** Area

**Note:** Exact

**From uom:** yd2

**To uom:** m2

**Factor:** 0.83612736

**Type:** Area

**Note:** Exact

**From uom:** m2

**To uom:** ft2

**Factor:** 10.7639104167

**Type:** Area

**Note:** Inverse of 0.09290304

**From uom:** bar

**To uom:** kPa

**Factor:** 100

**Type:** Pressure

**Note:** Exact

**From uom:** psi

**To uom:** kPa

**Factor:** 6.894757293

**Type:** Pressure

**Note:** Approximate to 9 digits

**From uom:** MPa

**To uom:** kPa

**Factor:** 1000

**Type:** Pressure

**Note:** Exact

**From uom:** h

**To uom:** min

**Factor:** 60

**Type:** Time

**Note:** Exact

**From uom:** min

**To uom:** s

**Factor:** 60

**Type:** Time

**Note:** Exact

**From uom:** day

**To uom:** h

**Factor:** 24

**Type:** Time

**Note:** Exact

**From uom:** dozen (DZ)

**To uom:** each (EA)

**Factor:** 12

**Type:** Count

**Note:** Exact

**From uom:** gross (GR)

**To uom:** each (EA)

**Factor:** 144

**Type:** Count

**Note:** 12 dozen

**From uom:** gross (GR)

**To uom:** dozen (DZ)

**Factor:** 12

**Type:** Count

**Note:** Exact

**From uom:** pair (PR)

**To uom:** each (EA)

**Factor:** 2

**Type:** Count

**Note:** Exact

**From uom:** ream

**To uom:** sheet

**Factor:** 500

**Type:** Count

**Note:** Common paper definition

**Notes:** Multiply the quantity in the From unit by the factor to get the To unit. To go the other way, divide. Conversion factors in your ERP should keep enough decimals; rounding a factor like 0.45359237 to 0.454 causes visible drift on large quantities. Pack sizes (case, pallet, reel) are item specific and are not listed here.

## Content

**Intro:** Wrong unit of measure conversions quietly corrupt purchasing, inventory value and costing. This reference lists common conversion factors, flags which are exact by definition, and explains how to hold them in an ERP item master without rounding errors.

**Sections:**

#### How to use the table

**Body:** Search by unit name or dimension, then multiply the quantity in the From unit by the factor to get the To unit. Divide to go the opposite direction. Use the table when you set up base and alternate UoMs on an item, when you check a supplier price unit against your stock unit, or when you review conversion records during a data migration. Export to Excel or CSV for use in a load template.

#### Exact versus approximate factors

**Body:** Many factors are exact since the inch, pound and gallon are defined in terms of metric units: 1 inch is exactly 25.4 mm, and 1 pound is exactly 0.45359237 kg. Others, such as psi to kPa, are derived and rounded. Keep as many digits as the ERP field allows. If a system limits decimals, prefer a numerator and denominator pair, if supported, over a rounded single factor.

**Bullets:**

- Exact: in, ft, yd, mile, lb, US gallon
- Derived: psi to kPa, barrel to liter
- Count units: dozen and gross are exact
- Pack sizes are item specific, never generic

#### UoM setup in an ERP

**Body:** Most ERPs keep one base unit per item and alternate units with a conversion factor. Choose the base unit as the smallest unit you track in stock, so quantities stay whole where possible. Purchase and sales units then convert into it. SAP material master holds alternative units of measure with a numerator and denominator, and many other systems store a single decimal factor. Check how yours treats rounding on receipt and invoice, since small differences multiply across thousands of transactions.

#### Common mistakes

**Body:** Mixing US and imperial gallons or short and long tons is the classic error and it is silent. Entering the factor in the wrong direction multiplies instead of dividing. Rounding factors to three decimals causes cost and quantity drift. Allowing free-text units creates duplicates like EA, EACH and PC. Changing the base unit of an item with stock or open orders is dangerous and should be done only through the ERP's supported process, if at all.

**Cta:** If you are cleaning UoM data across thousands of items, we can help build a read-only scan that flags inconsistent or implausible conversions in your ERP.

**Faq:**

#### What base unit of measure should I choose for an item?

**Answer:** Use the smallest unit you need to track in stock so that quantities stay whole where practical, for example each or gram. Larger purchase and sales units then convert into it. Avoid changing it later once stock and transactions exist.

#### Are US and imperial gallons the same?

**Answer:** No. A US gallon is exactly 3.785411784 liters and an imperial gallon is exactly 4.54609 liters, about 20 percent larger. Confirm which one a supplier uses before setting a conversion.

#### How many decimals should a conversion factor have?

**Answer:** Keep as many as your ERP allows, at least six for derived factors. Exact factors such as 25.4 or 0.45359237 should be stored in full. Where possible use a numerator and denominator to avoid rounding altogether.

#### Does this table include pack sizes like case or pallet?

**Answer:** No. Case, box, reel and pallet quantities depend on the item and the supplier, so they must be entered per item from the packaging specification, not from a generic table.

## Search terms

unit of measure conversion table, ERP unit of measure conversion, UoM conversion factors, inches to mm conversion factor, pounds to kg factor, item master UoM conversion, SAP unit of measure conversion, gallon to liter conversion

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