Nitro PDF Pro 13.3.1 Mac

Anyone who has used Apple Preview to fill out a form knows its limits the moment a document needs more than a signature. Nitro PDF Pro steps into that gap on the Mac, offering a full editor without leaving the desktop.

Take a scanned contract that arrives as a flat image. You can run the built-in OCR to pull out searchable text, then switch to the edit tool and correct a misspelled company name directly in the text block. Add a digital signature from a saved file, drop in a comment for the sender, and export the result as a clean PDF — all in one app.

Preserving fonts and layouts when copying from PDFs

• Preserving fonts and column layouts when copying rich text from a PDF.
• Creating cross-platform fillable forms that work outside the Apple ecosystem.
• Redacting sensitive information.
• Converting entire websites into multi-page PDFs with working hyperlinks.

Audio annotations need a mic; text editing flows in blocks

• Recording and playing audio annotations requires a microphone and speakers.
• Editing text happens inside adjustable text blocks, which can behave differently than a word processor.

A 50-page manual idles at 380 MB on an M1 Air

Opening a fifty-page equipment manual on a MacBook Air M1, Nitro PDF Pro settles into about 380 MB of RAM after a few minutes of scrolling and minor annotations. That number creeps up when OCR kicks in on scanned pages, but it drops back once the recognition pass finishes. On an Intel machine with 8 GB of memory, the same file hovers closer to 500 MB during editing — noticeable but not punishing if only a handful of other apps are running.

Launch time from the dock sits around four seconds on Apple Silicon and closer to eight on an older Intel Mac. That gap shrinks after the first cold start, since macOS caches the binary. Once open, page rendering keeps up with brisk scrolling through mixed text-and-image documents. The only real hitch appears when dragging a large image into a PDF already packed with high-resolution photos; the canvas can stutter for a beat before the object snaps into place. Saving the file after that kind of insertion is quick, however, with a ten-page document clocking under a second.

Stability holds well during everyday tasks. Opening, marking up, signing and exporting a batch of five documents in a row rarely triggers a crash. Where users should save before experimenting is the website-to-PDF converter. Complex pages with embedded video placeholders and heavy JavaScript sometimes produce a spinning beachball that lasts fifteen seconds or more. The resulting PDF usually comes through intact, but a small fraction of pages — maybe one in twenty — lose a sidebar or drop a navigation bar. When that happens, re-running the capture with a simpler page view helps.

Launch it alongside Preview, not instead of it

Nitro PDF Pro does not try to replace Preview; it sits next to it. You can keep Preview as the default double-click opener for light reading and launch Nitro only when editing, OCR or form work is needed. The app registers as a PDF handler, so right-clicking a file in Finder and choosing Open With routes it straight into Nitro. The share sheet also picks up the app, meaning a PDF arriving in Mail can jump to Nitro with two clicks, get annotated, and return as a reply attachment.

Copy and paste between Nitro and Microsoft Word preserves fonts and column structures better than extracting text through a plain-text intermediary. Pull a section from a financial report in Nitro, paste it into Word, and the paragraph keeps its bold headings and indented bullet points. The same flow works in reverse: a formatted Word document exported to PDF opens in Nitro with editable text blocks that respect the original spacing.

Spotlight indexes the text layer of any PDF saved from Nitro, provided OCR has been run on scanned pages first. Searching for a client name buried in a fifty-page scanned contract from six months ago brings up the file in Finder results. The app also respects macOS Continuity Markup, so an iPad can grab a PDF via Sidecar and let the Apple Pencil add handwritten notes that appear in Nitro as embedded annotations.

Offline OCR handles your bank statement without phoning home

Does the OCR need an internet connection? No. The text recognition engine runs locally on the Mac, so a scanned bank statement processes fully offline. The trade-off is that recognition accuracy depends on the scan quality rather than a cloud service cleaning it up first.

Will it feel familiar if I came from the Windows version? The Mac edition shares the core feature set — editing, OCR, form creation, redaction — but the interface follows macOS conventions instead of a Windows ribbon. Keyboard shortcuts match what Mac users expect, and the toolbar arranges tools in a single row rather than tabbed panels. The workflow is close enough that moving between platforms does not require relearning the basics.

Can it flatten annotations so they cannot be removed? Yes. After adding comments, stamps or signatures, the flatten function bakes them into the page content layer. The flattened file shows no annotation objects in any reader, which matters when sending a signed contract to someone who might otherwise edit the signature box.

How does redaction actually work? Marking text for redaction draws a black box, but the important step happens on save. The app strips the underlying text from the file data, not just from the visible layer. Searching the redacted PDF for the hidden text returns nothing. Skipping the save step, however, leaves the text intact underneath the black rectangle.

Annotation tools grouped into a three-button markup cluster

Version 13 brought a redesigned annotation toolbar that groups markup tools by type rather than scattering them across a single row. Highlight, underline and strikethrough now sit in a compact three-button cluster, and the colour picker stays visible after the first selection instead of collapsing. For anyone marking up research papers or contracts daily, that cuts a click out of every colour change.

The text editing engine received a quiet but practical update: text blocks now respect the original line spacing more closely when inserting new words into a paragraph. Earlier versions occasionally pushed lines apart when adding a sentence mid-block. As of version 13.3.1, the reflow behaviour is tighter, though it is still not a word processor — adding three lines to a tightly packed paragraph can nudge the overflow past the bottom margin.

OCR got a speed bump on Apple Silicon. A scanned ten-page document that took around forty seconds on an Intel Mac now completes in roughly twenty-five seconds on an M-series chip. The recognition dictionary also expanded for English, catching more legal and medical terms without manual correction.

Batch processing became more practical for regular use. Selecting a folder of scanned invoices and running OCR on all of them at once now shows a progress bar per file rather than one vague overall bar, so you know which document is stalling. The exported Office formats gained tighter table fidelity, particularly for bordered tables moving into Excel, where column widths now mirror the PDF layout more faithfully than in the 12.x releases.

• macOS 10.14 Mojave or later
• Intel and Apple Silicon Macs
• 1 GB RAM
• Up to 2 GB available disk space
• Display resolution of at least 1280x800