Convert mm to inches in Excel

Hidden in the Engineering category is a useful function that is for more than just engineers. The CONVERT function, which has been available since Excel 2007, allows you to easily convert almost anything from one metric to another e.g. convert mm to inches in Excel without trying to do the complex maths or remembering what the values are down to the 10th decimal.

The syntax is pretty simple

= CONVERT (  the number   ,  from unit   , to unit   )

The number is obvious. The from and to unit allows for a number of variations but you need to know the letters to use. Below we have listed the ones we feel are the most useful for  the most people.

In this case the function wizard doesn’t provide the full list but you can use help, or when you enter the formula directly into the formula bar you will receive some help as shown below.


In the example above we have shown some of the typical conversions. Just remember that the text e.g. mm needs to be in inverted commas.

Below the ones we have found most useful and practical in everyday use. For the full list you can see the CONVERT help page on Microsoft

Most Useful Conversions in Excel

Weight and mass

  • Gram                                                                              “g”
  • Pound mass (avoirdupois)                                             “lbm”
  • Ounce mass (avoirdupois)                                            “ozm”
  • Stone                                                                             “stone”
  • Ton                                                                                “ton”
  • Imperial ton                                                                    “uk_ton” or “LTON” (“brton”)


  • Year                                             “yr”
  • Day                                              “day” or “d”
  • Hour                                            “hr”
  • Minute                                         “mn” or “min”
  • Second                                         “sec” or “s”


  • Meter                                                                                            “m”
  • Statute mile                                                                                   “mi”
  • Nautical mile                                                                                  “Nmi”
  • Inch                                                                                               “in”
  • Foot                                                                                               “ft”
  • Yard                                                                                               “yd”
  • U.S survey mile (statute mile)                                                         “survey_mi”


  • Degree Celsius                                                             “C” (or “cel”)
  • Degree Fahrenheit                                                       “F” (or “fah”)
  • Kelvin                                                                           “K” (or “kel”)


  • International acre                                        “uk_acre”
  • U.S. survey/statute acre                               “us_acre”
  • Square feet                                                  “ft2” or “ft^2”
  • Hectare                                                       “ha”
  • Square inches                                              “in2” or “in^2”
  • Square light-year                                         “ly2” or “ly^2”
  • Square meters                                             “m2” or “m^2”
  • Square miles                                                “mi2” or “mi^2”
  • Square nautical miles                                   “Nmi2” or “Nmi^2”
  • Square yards                                               “yd2” or “yd^2”


  • Bit                                                                  “bit”
  • Byte                                                               “byte”


  • Knot                                                                             “kn”
  • Meters per hour                                                           “m/h” or “m/hr”
  • Meters per second                                                       “m/s” or “m/sec”
  • Miles per hour                                                              “mph”


  • Electron volt                                                                          “eV” (or “ev”)
  • Horsepower-hour                                                                  “HPh” (or “hh”)
  • Watt-hour                                                                             “Wh” (or “wh”)
  • Foot-pound                                                                           “flb”
  • BTU                                                                                       “BTU” (or “btu”)

Volume (or liquid measure )

  • Teaspoon                                                               “tsp”
  • Modern teaspoon                                                  “tspm”
  • Tablespoon                                                            “tbs”
  • Fluid ounce                                                            “oz”
  • Cup                                                                       “cup”
  • U.S. pint                                                                 “pt” (or “us_pt”)
  • U.K. pint                                                                 “uk_pt”
  • Quart                                                                     “qt”
  • Imperial quart (U.K.)                                               “uk_qt”
  • Gallon                                                                    “gal”
  • Imperial gallon (U.K.)                                              “uk_gal”
  • Liter                                                                       “l” or “L” (“lt”)
  • U.S. oil barrel                                                          “barrel”
  • U.S. bushel                                                             “bushel”
  • Cubic feet                                                              “ft3” or “ft^3”
  • Cubic inch                                                             “in3” or “in^3”
  • Cubic meter                                                           “m3” or “m^3”
  • Cubic Mile                                                             “mi3” or “mi^3”
  • Cubic yard                                                             “yd3” or “yd^3”
  • Cubic nautical mile                                                 “Nmi3” or “Nmi^3″3”