A PDF form field keeps two separate things: the value that was entered, and a small drawing of that value, called the appearance stream, which is what a viewer paints on the page. Software that fills a form by writing the value only, a script, a web service or a library used without its "update appearances" step, leaves the drawing empty. The data is in the file, but the field can look blank, depending on the viewer.
This checker opens a filled PDF form as data, goes through every field and widget, and tells you which filled fields have a drawing that matches their value and which do not. The PDF is read in your browser and is not uploaded. It reports what the file contains; it does not claim the form will display correctly in every viewer.
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Overview
About PDF Form Appearance Checker
What it looks at. An interactive form is a list of fields (ISO 32000-1, clause 12.7); each field is shown on a page by one or more widget annotations (12.5.6.19). A widget is drawn from its normal appearance stream (/AP /N). For each filled field the checker reads the stored value, the field type and flags, the widget's rectangle, annotation flags and appearance, and compares them.
What it can say.
- No appearance stream: a value is stored but the widget has nothing to draw. Some viewers rebuild it from the default appearance string (
/DA); many viewers and preview tools do not. With theNeedAppearancesflag set the result is softened to a warning, because viewers that honour the flag rebuild all fields when the file opens. - Blank appearance: the stream exists but draws no text.
- Value mismatch: the stored value and the drawn text differ, so what you see and what the form data says are not the same.
- Check boxes and radio buttons: the value or state names a drawing the widget does not have, or the widget stays in its "Off" state while the field says it is on.
- Hidden or misplaced: the Hidden or NoView flag, a collapsed rectangle, a position outside the page boundary, or a layer that is switched off.
- Fragile rebuilds: a default appearance that names a font missing from the form's font resources, text that is white or very small.
Output. A verdict, a list of the fields to check with page and explanation, and a list of the fields that look fine. The report can be downloaded as JSON. An XFA form is noted because viewers that support XFA can show data that is stored apart from the fields checked here.
Related, but different. This tool answers "does the value appear on screen?". Whether form elements are included in a printout depends on other flags; use the PDF Form Printability Checker for that.
Read more. The guide Why a filled PDF form looks blank or prints empty explains the difference between a field's value and its drawing, and how printing differs.
Compatibility
Supported Formats
PDF files with an AcroForm up to 80 MB. Text fields, check boxes, radio buttons, drop-downs and list boxes are checked; push buttons and signature fields are skipped. Password-protected PDFs are refused with a message. XFA-only forms have no AcroForm fields to read.
Guide
How to Use PDF Form Appearance Checker
- Drop the filled PDF form onto the box. It is read in your browser.
- Read the verdict and the numbers: filled fields, fields with a matching appearance, fields to review, fields likely to show blank.
- Open the list of fields to check. Each line names the field, its page, the stored value and the reason.
- Fix the cause in the program that filled the form (for example update field appearances before saving) or flatten the form, then check the new file again.
Highlights
Features
- Value versus drawing Compares each stored value with the stored appearance of its widget.
- Every field type Text, check box, radio button, drop-down and list box fields, with their states.
- Hidden and off-page fields Hidden and NoView flags, collapsed rectangles, positions outside the page and layers that are off.
- Plain-language reasons Each finding says what is wrong and why a viewer may show the field empty.
- Local and read-only The PDF is read in your browser and never changed or uploaded.
Applications
Use Cases
- A form filled by a script or a web service shows empty fields in a browser or on a phone
- Checking an automatically generated PDF before it is sent to customers
- Finding out whether a field is empty or only drawn empty
- Spotting hidden or off-page fields that still hold data
- Explaining to a developer exactly which fields lack an appearance
Good to Know
Limitations
The check reads the file's structure. It does not render the page, so it cannot see how a particular viewer, browser or phone app draws a field, and viewers genuinely differ: some rebuild a missing appearance, some do not, and behaviour changes between versions. The tool therefore makes no claim of compatibility with any viewer.
Text compared between the stored value and the drawn text is limited to plain text in simple fonts; fields using composite fonts, password fields, comb fields and rich text are checked for a drawing only. It does not fix anything and does not change the file.
This tool runs entirely in your browser — your file is never uploaded to our servers. See our Privacy Policy for full details.
Support
Frequently Asked Questions
Why does my filled PDF form look empty in Chrome or on my phone?
Often because the program that filled it wrote the field values but not their appearances. Adobe Acrobat can rebuild a missing appearance on opening; many browsers and mobile viewers only draw what is stored. This checker shows which fields have no stored drawing.
Is my PDF uploaded?
No. The file is opened and analysed in your browser and is not sent to our server or to any other service.
What does the NeedAppearances flag mean?
It asks a viewer to rebuild every field appearance when the file is opened. Viewers that honour it show the values; viewers and print pipelines that ignore it use the stored appearance streams, so a form that relies on the flag can still look blank elsewhere.
Does a clean result mean the form looks right everywhere?
No. It means the stored appearances match the values. Viewers have their own quirks with fonts, comb fields and rich text, and printing follows separate rules.
How can I fix the fields it flags?
Regenerate the appearances in the tool that created the file (many libraries have an update-appearances call that must run before saving), or flatten the form so the values become page content. Then check the new file again.
What is the difference to the PDF Form Printability Checker?
This tool asks whether the filled value is drawn. The printability checker asks whether form elements are included in print output, which depends on the Print flag, the page boundary and layers. A field can show on screen and still not print, or print and not show.
Keep Going
Related Tools
- PDF Structure & Validity Checker Check a PDF's internal structure for damage most viewers silently repair and never tell you about — free and instant.
- PDF Font Checker List the fonts in a PDF: type, embedded or not, subset, encoding, and the pages that use them. Warns about fonts that are missing from the file. Export a report. In your browser.
- Flatten PDF Turn form fields and annotations (stamps, highlights, ink, shapes) into ordinary page content so a PDF looks the same everywhere. Explains what changes, including signatures. In your browser.
- PDF Form Printability Checker Check whether the interactive fields of a PDF form will be included when it is printed: Print and Hidden flags, appearance streams, page boundary and layers, page by page. In your browser.