PDF Editor

How this PDF editor keeps the original font

Most free PDF editors replace the text you change with Arial or Helvetica, so the edited line stands out from the rest of the page. This one reuses the font that is already inside the PDF:

• Same font object. A PDF stores its fonts inside the file. When you change a line, the new letters are written with that same stored font, at the same size and angle, starting where the old line started.
• Letters the PDF doesn’t have. PDFs usually keep only the letters the document uses, to stay small. If you type a letter that was never used, say a capital Q in a file with no Q in it, that one letter comes from the same font family online. Calibri, Arial, Times New Roman, Cambria, Courier New and Georgia get look-alikes with the same letter widths (Carlito, Arimo, Tinos, Caladea, Cousine and Gelasio). Only when the family can’t be found is the closest match used.
• You are told which font is used. Under the text box the editor names the font, and lists any letters it had to take from another font. Nothing is swapped silently.
• Colours picked from the page. The text colour and the background behind the line are read from the page, so the new text has the same colour and the cover blends into coloured boxes and table rows.

How to edit text in a PDF

1. Drop a PDF into the box above, or tap it to browse. The editor reads the fonts on every page, then shows the pages.
2. Keep Edit text selected and click the line you want to change. A box opens with the current text.
3. Type the new text. The page updates as you type, in the PDF’s font.
4. Check the note under the box. It says which font is used and whether any letters came from another font.
5. Press Enter or tap Done. Repeat for other lines.
6. Tap Download PDF. The edited file is saved with “-edited” added to its name.

Add text and white out

Add text places new text anywhere on a page: click the spot, type, and pick the size and font. The font list shows the fonts this PDF already uses, so a filled-in form or a note matches the document. Noto Sans is offered too, for PDFs whose fonts can’t be reused.

Whiteout covers part of a page with a white box. Drag over the area to hide. Use Undo to take back the last change of any kind.

What gets edited and what doesn’t

Limitations

• The old text stays in the file. Changed text is drawn over a cover of the background colour. The old words are hidden, but they are still inside the PDF and can be copied out. Don’t use this to hide account numbers or other private details. For that, use a redaction tool that deletes the text.
• One line at a time. Each line is edited on its own. Longer text doesn’t move onto the next line or push other lines down, so a much longer sentence runs past the old one.
• Hindi and other Indian languages. Letters are placed one by one, so letters that should join into one shape may show separately. Check the page before you download.
• Letter spacing. If the PDF spreads letters out with extra spacing, the new text uses the font’s normal spacing.
• Locked PDFs. Files with a password or edit restrictions, such as many bank statements, can’t be saved after editing, so they aren’t opened.

Key facts

• Fonts inside a PDF are often subsets that hold only the characters the document uses. (ISO 32000-1, section 9.6.4 Font Subsets (opens in new tab))
• Pages are read with Mozilla’s PDF.js, the PDF engine in Firefox, and saved with the open-source pdf-lib library. (PDF.js (opens in new tab), pdf-lib (opens in new tab))
• Missing letters come from Fontsource, which serves open-source fonts such as those on Google Fonts. Only the font name is requested, never your document. (Fontsource (opens in new tab))