22-second walkthrough
One PDF. Five spreadsheet rows. One ZIP.
A real production workflow with a synthetic vendor form and a five-row Excel workbook: match all nine fields, review every PDF, and export one ZIP.
- 1Review nine PDF fields once
- 2Match 9/9 Excel headers
- 3Approve five and export ZIP
PDF mail merge, without Word
How to fill multiple PDF forms from Excel
Keep the original PDF layout. Put column names in the first spreadsheet row and one customer, employee, vendor, or case in each row below it. JustFill creates a separate PDF for every selected row.
- 1
Upload the original PDF
Use an AcroForm, a flat PDF, or a scan. JustFill detects the fields before the merge.
- 2
Import XLSX or CSV
Dates, leading zeros, percentages, booleans, and spreadsheet headers are preserved for mapping.
- 3
Check the column mapping
Matching headers map directly. Ambiguous columns can use AI-assisted mapping.
- 4
Review and export
Approve the records you want and download individual filled PDFs in one ZIP.
Sample input
One normal Excel column splits cleanly into individual PDF character boxes
| 9-Box EIN / SSN Column | 12-Box Account / Claim ID | 8-Box Date (MMDDYYYY) |
|---|---|---|
| 842910441 → [8][4][2][9][1][0][4][4][1] | CLM202600142 → 12 character cells | 10252026 → [1][0][2][5][2][0][2][6] |
| 753829104 → [7][5][3][8][2][9][1][0][4] | CLM202600143 → 12 character cells | 10262026 → [1][0][2][6][2][0][2][6] |
| 825104923 → [8][2][5][1][0][4][9][2][3] | CLM202600144 → 12 character cells | 10272026 → [1][0][2][7][2][0][2][6] |
9-Box EIN / SSN Column
842910441 → [8][4][2][9][1][0][4][4][1]
12-Box Account / Claim ID
CLM202600142 → 12 character cells
8-Box Date (MMDDYYYY)
10252026 → [1][0][2][5][2][0][2][6]
Click any spreadsheet row above to preview its generated PDF. All 3/3 columns auto-matched by AI.
Upload any PDF with character grids or partitioned boxes
Open your government, tax, banking, title, or settlement PDF. JustFill automatically unifies adjacent character boxes or lets you drag one rectangle across the grid.
Set field type to Comb & adjust the box count
Choose "Comb (Character Boxes)" in the field toolbar and set the exact cell count (e.g., 9 for SSN/EIN/ABA, 8 for Date, 10–12 for Claim ID, 17 for VIN).
Type once or batch-import 100+ rows from Excel/CSV
Keep full strings in a single spreadsheet column. JustFill centers each character inside its own box and exports a clean PDF or multi-file ZIP.
Where it fits
The fastest government form character grid PDF filler — single form or 500-row Excel batch.
Government tax forms (W-9, SS-4, 2848, UK HMRC, DE Elterngeld, FR Cerfa), auto title applications (Texas 130-U 17-char VIN), banking ACH mandates, and class-action claim forms use partitioned character boxes so optical scanners can read them. JustFill lets you fill PDF character boxes automatically from one normal text box or batch fill PDF boxes one letter per box from Excel.
32-second video walkthrough
Watch: PDF Comb Field & Character Box Filler in 32 seconds
See the live browser workflow: upload one PDF template, import your Excel (.xlsx) or CSV spreadsheet, auto-match columns to detected PDF fields, preview every record, and download one filled PDF per row in a clean ZIP.
Simple pricing
Test comb character box alignment free in your browser — single PDF or 5-row sample batch.
Your first single-form clean download is free, and the 5-row guided batch preview requires no credit card. Upgrade to the $7 7-Day Pass (up to 25 PDFs), Starter ($19/mo, 25 rows/batch, 125 clean output pages per month), Pro ($49/mo, 100 rows/batch), or Business ($99/mo, 500 rows/batch).
$7 7-Day Pass — One-off batch up to 25 rows (25 clean PDFs in a batch ZIP + 25 AI credits, no subscription, $7 credited toward Starter)
Need recurring monthly runs, saved templates, and 125 clean output pages/month with AI column mapping? Choose $19/month Starter above.
Get $7 7-Day Pass (up to 25 rows)Running larger spreadsheet batches? Get Pro — $49/month for up to 100 rows per batch (or Business at $99/month for up to 500 rows).
Starter
Recommended first workflow
- AI field detection for 250 new pages per month
- Reusable templates — refills use no detection pages
- Up to 25 PDFs per batch
- 125 clean output pages per month
- Clean, watermark-free ZIP exports
- CSV and XLSX spreadsheet imports
- Review every record before export
Paid workflow
Never split a string across 17 spreadsheet columns again.
Other PDF tools treat a 12-box Claim ID or 17-box VIN as 12 or 17 separate form fields, forcing you to split strings with Excel MID() formulas. JustFill treats the entire character grid as one logical field.
Adjustable Comb box count with live visual dividers
See the vertical cell dividers live on the PDF canvas as you adjust the box count so every character lands dead-center in its printed cell.
One Excel column → N character boxes
Map a single CSV or XLSX column (like `842910441` or `1FTFW1E50MFA00101`) directly to a comb field without splitting characters across columns.
Save calibrated comb templates for repeat runs
Save your comb box geometry once and reuse it on every weekly vendor, title, or claimant batch.
Guardrails
Draft preparation with human review.
Clear boundaries
JustFill formats and places user-supplied strings into PDF character grids. Always preview the generated PDF to confirm character spacing and box count match the issuing agency or administrator’s specifications.
Beyond manual uploads
Run the same PDF workflow from an AI agent or n8n.
The browser flow is the fastest way to validate a spreadsheet and PDF. Once the mapping works, the same JustFill account can expose PDF detection, filling, and saved templates through the hosted MCP endpoint.
ChatGPT, Claude and MCP
Give an agent a PDF, inspect detected fields, fill it, and save the reviewed layout for repeat use.
n8n automation
Trigger fills from a webhook, spreadsheet, CRM, or database and send the result to your next workflow node.
PDF Mail Merge Software
Browser-based PDF mail merge software to batch fill fillable, flat, and scanned PDFs without Acrobat plug-ins or VBA macros.
Fill Applications for Clients
Prepare recurring official forms, permits, and intake packets across client rosters from one structured spreadsheet.
Frequently asked questions
How do I fill PDF character boxes automatically without clicking every single box?
Upload your PDF to JustFill, select or draw a single field spanning the entire row of character boxes, and switch its field type to "Comb (Character Boxes)" with the matching number of cells (for example, 9 boxes for an EIN or 17 boxes for a VIN). When you type or paste a string, JustFill distributes one character into each box automatically.
Can I batch fill PDF boxes one letter per box from Excel or CSV?
Yes. Keep the full value (such as `842910441` or `CLM202600142`) in a single Excel or CSV column. Map that column to your Comb field in JustFill’s Batch mode, and every generated PDF in your exported ZIP will have its characters spaced cleanly into the individual boxes.
What if my Excel column has dashes or spaces (like 84-2910441) but the PDF comb grid only has 9 boxes for digits?
You can either strip dashes in your spreadsheet or use our inline batch grid editor in the browser to preview and adjust the exact characters that populate the 9 comb cells before downloading the ZIP.
Why does Adobe Reader or another PDF filler put my whole text string into the first tiny box?
On flat PDFs or poorly constructed government forms, each printed square is either just a drawn graphic line (0 AcroForm fields) or an unlinked 1-character box. JustFill’s government form character grid PDF filler unifies the row into a true multi-cell Comb field with evenly spaced character slots.
Can I export an interactive fillable PDF where the recipient’s typing also jumps box-to-box?
Yes! On Starter ($19/month), Pro ($49/month), and Business ($99/month) plans, exporting as an Interactive AcroForm sets the official PDF `Comb` flag and `maxLen` on the field so recipients opening the file in Adobe Acrobat Reader automatically get 1-character-per-box spacing too.
Does it work with scanned or flat PDFs?
Yes. JustFill detects field locations in fillable, flat, and scanned PDFs before mapping spreadsheet columns.
Does each spreadsheet row create a separate PDF?
Yes. The first row contains the Excel or CSV column names. Every selected data row becomes one reviewable PDF in the exported ZIP.
Is this the same as Word mail merge?
It uses the same one-row-per-document idea, but fills your existing PDF directly. You do not need to recreate the form in Word or convert the PDF first.
Can I review results before downloading?
Yes. Each spreadsheet row becomes a reviewable record. Approve the records you want before creating the ZIP.
Does JustFill email the generated PDFs?
Not in the current self-service batch. It creates individual PDFs and packages the approved files in a ZIP for download.
What happens to uploaded documents?
Transfers use TLS. Rendered page images are deleted within 7 days and source documents within 30 days unless you save the PDF as a reusable template.