I'm trying to add a field to my attribute table that shows the percent of acres per land use. I tried using this approach enter link description here

but I couldn't seen to get it to work for me. I know that I'm missing something so simple but being that I'm new to using ArcMap, I'm having great difficulty.

Table I have:

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Table I want:

enter image description here


Right click on Acres, select "Statistics..." This will show a small window with a frequency table and some summary statistics for that field. Write down the Sum, which should add up all the acres.

Create a new field, something like Percent_Acres, with the data type set to Double. Right click on your new empty field and select Field Calculator. In the field calculator window, write the formula

([Acres]/the sum you just wrote down)*100

Hit ok to calculate the field.

  • thank you for your answer! It keeps giving me the following error: There was a failure during processing, check the geoprocessing results window for details.. Any idea why its doing this? – NBE Aug 3 '18 at 18:16
  • typical reasons for that: you're trying to divide something by 0, one of the fields being calculated is the wrong data type like a string, there's a join on your table. check that Acres and Percent_Acres fields are the same data type. most of the time for me it's because something is trying to divide by 0. – rachel.passer Aug 3 '18 at 18:20
  • Gotcha.. they have both the same data type and there isn't anything dividing by 0. I wonder what else it could be. – NBE Aug 3 '18 at 18:24
  • see if you have editor on, if you have any rows selected, if you have the table open in any other GIS program (arccatalog etc). it could be many things. – rachel.passer Aug 3 '18 at 18:26
  • 1
    I figured it out! I forgot I changed the name of the field and I wasn't using the original name! Thanks! – NBE Aug 3 '18 at 18:35

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