What the PDF Form Field Inspector does
This inspector lists every fillable field in a PDF form - its full name, type (text, checkbox, radio group, combo or list box, push button, signature), current and default value, options and export values, the required, read-only, multi-line, password and comb flags, the tooltip, the maximum length, and the page and rectangle where it sits - and flags the fields that will cause trouble.
It is the field map you need before you merge data into a form, write code that fills it, or hand it to someone who has to make it accessible. The PDF is parsed in your browser by this page's own reader; form scripts are counted and never run, and nothing is uploaded.
How to use it
- Drop a fillable PDF, or load the membership-form example.
- Read the findings: unnamed fields, names that clash, and fields without tooltips are the usual problems.
- Use the table to look up a field by name, type or value. The full name is the dotted name that data files, scripts and form-filling libraries use.
- Download the field map as CSV or JSON, or copy the list of names to build a data file for a mail merge.
Reading the results
Full name joins the partial names of a field and its parents with dots, so a field called email under a parent called applicant is applicant.email. That full name is what FDF and XFDF data files, JavaScript and most PDF libraries use to find a field.
Type comes from the field's FT entry and its flags: a button field is a checkbox, a radio group or a push button depending on flags 16 and 17; a choice field is a combo box when flag 18 is set and a list box otherwise.
Options shows a choice field's list as display text with the export value in brackets, and a checkbox or radio group's export values - the values that are saved when the box is on. A checkbox whose export value is not Yes surprises many data-merge tools.
Problems: an unnamed field cannot be addressed at all; two fields whose names differ only in case clash in many export formats and databases; and a field without a tooltip is announced to screen-reader users only by its internal name.
Worked example: a club membership form with four planted problems
The example form has 11 terminal fields on one page. applicant.name is a required text field already filled with Jordan Ellis; applicant.email sits under the same parent. dob is a comb field with a maximum length of 10 characters, consent is a required checkbox set to Yes, contact_pref is a radio group set to Phone, membership is a combo box with three options (ADULT is selected), and office_notes is a read-only multi-line field. submit is a push button with a JavaScript submit action, which is counted but not run.
The inspector reports six problems. One field has no name at all (an error). Phone and phone differ only by case, so both are flagged as duplicates. And three fields - applicant.email, the unnamed field and phone - have no tooltip, so a screen reader would read out nothing useful.
Limitations: what the result does not prove
- Only AcroForm fields are listed. Pure XFA forms (from older LiveCycle Designer) store their fields in XML that is not parsed here; the tool says when XFA is present.
- Values are what the file stores. A viewer may show a calculated or formatted value that differs, because calculation and formatting scripts are not run.
- Positions are in PDF points (1/72 inch) from the page's lower-left corner, before any page rotation.
- Encrypted PDFs can be opened only when their strings are not needed: field names and values in an encrypted file cannot be decrypted here.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- ISO 32000-2 (PDF 2.0) - PDF Association resources - checked 19 Sep 2026
- ISO 32000-2:2020 PDF 2.0, section 12.7 Forms
- Adobe - PDF Reference, sixth edition (PDF 1.7), section 8.6 Interactive forms
- W3C - PDF12: Providing name, role, value information for form fields in PDF documents
- Adobe - Acrobat JavaScript API reference (Field object)
Frequently asked questions
How do I find the field names in a fillable PDF?
Drop the PDF here and every field's full dotted name is listed, with a button to copy all the names at once. Those are the names that FDF and XFDF files, JavaScript and form-filling libraries such as pdf-lib or iText expect.
Why does my checkbox export 'On' or '1' instead of 'Yes'?
A checkbox's saved value is the name of its 'on' appearance, which the author chose. The inspector lists each checkbox's export values so you can see exactly what will be written when it is ticked.
What is a comb field?
A comb field spreads its characters evenly across a fixed number of boxes, like a printed form with one letter per square. It needs a maximum length, which the inspector shows next to the comb flag.
Why are two fields with the same name a problem?
Fields with exactly the same full name are the same field and always share a value. Names that differ only in case, such as Phone and phone, are different fields to a PDF but collide in many spreadsheets, databases and export tools.
Does this tool fill in or change my form?
No. It only reads the file and reports what is there. The original PDF is not modified, no script inside it runs, and nothing leaves your browser.
Why does it say my PDF has no form when I can see boxes?
Lines and boxes drawn on the page are just graphics. Unless the PDF has an AcroForm with field objects, there is nothing to fill in; a form tool must add real fields first.
Last reviewed by the A2Z.Tools team against the sources listed above.
