Answer piping: use previous form answers
Base logic in form fields on previous answers or use them to personalize your form with answer piping. Display read only fields.
In many places in Fillout, you may notice a blue (+) button. This lets you reference
- previous form inputs
- URL parameters
- dates (e.g. "today", "a month from now", etc.)
Referencing from the blue (+) buttons
Whenever you see this blue (+), you can reference a previous form input by pressing the button and hitting "Continue" on the page you'd like to reference from:

Then, we can press "Insert" on any of the fields we'd like to reference:

Referencing in field logic
To base show/hide logic for fields on previous form inputs, we can click the "Logic" section on a field and "Set conditional logic." Here, every time we click "Pick reference", the same menu/dropdown as above will be visible. Click here for more details.
Referencing in headings/question labels
To reference previous form inputs in plaintext in the form, we can type "@" in a form field to show the reference menu as above:

Once inserted, you can always hover over the blue tag to see a more full description of what you inserted.