I am trying to have a new field with the same content of an existing field.

In ArcGIS I would normally use the Field Calculator to make this instantly.

In QGIS I have followed the same steps (create new field, open field calculator, make it equal to an existing field) but it doesn't work... meaning nothing changes, the new field remains empty...

enter image description here

Any suggestions?

  • Welcome to GIS SE! We're a little different from other sites; this isn't a discussion forum but a Q&A site. Your questions should as much as possible describe not just what you want to do, but precisely what you have tried and where you are stuck trying that. Please check out our short tour for more about how the site works
    – Ian Turton
    Commented Mar 10, 2021 at 11:16
  • 2
    Please give us a clue, what doesn't work? How do you make it equal to an existing field?
    – Ian Turton
    Commented Mar 10, 2021 at 11:16
  • 4
    If you want to set field 2 equal to field 1 you use "field 1" in the field calculator.
    – Erik
    Commented Mar 10, 2021 at 11:18

2 Answers 2


First check that edit mode is turned on. Then instead of putting into the expression window PercentTF = Wards_wi_6 as you currently have it, just put "Wards_wi_6" (i.e. enclosed in double quotes") and press ok. You have already specified in the upper dialogue box where you want the result.


If a new layer can/may be created instead of changing the existing one, there is a possibility using the 'Refactor fields' tool.

Input layer: input

Refactor fields: rf_menu

Output layer: output

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.