ABOUT
About Redline PDF.
Redline PDF is software for reviewing PDF construction drawings. Calibrate a sheet, mark it up, measure it, and send a clear result, all in your browser.
What it does
Open a PDF drawing, calibrate the sheet against a dimension you trust, and review it with clouds, callouts, text, stamps, measurements and counts, and with walls, doors and windows that carry their sizes. Redline also reads the annotations already in a PDF someone sends you. With Plus or Pro, export a PDF with editable annotations or a clean PDF, and with Pro a CSV of quantities; Free exports a flattened PDF.
Who it is for
The architect, engineer or reviewer who checks drawings on their own. Established drawing review software is mostly sold to firms, per seat, as desktop programs. Redline is priced for one person, in a web browser, on Windows, a Mac or an iPad.
How your drawings are kept
A drawing you save belongs to your account and is encrypted on the server. No other account can open it, and you can download your drawings at any time, during the trial and after it. Subscriptions are sold through Paddle, the merchant of record, so card details go to Paddle, never to Redline. The privacy policy has the detail.
How it is priced
Every account starts with 30 days of Pro, no card. After that you keep Redline Free for as long as you like, or choose Plus at $9 a month or $90 a year or Pro at $15 a month or $150 a year; your drawings stay either way. Compare the plans.
How it changes
Redline is updated often, and every update is written up. The latest shipped on 25 October 2026. See what’s new.
About the name
This Redline is software for PDF drawings, and redlinepdf.net is its home. Businesses elsewhere that trade as Redline Services, in fields such as heating, IT and telecoms, are separate companies.
Talk to us
Contact Redline PDF support and a person answers. In the app, Help sends a problem report or a rating straight to us.
What is Redline PDF?
Redline PDF is browser-based software for reviewing, marking up and measuring PDF construction drawings. It runs at redlinepdf.net with nothing to install, on Windows, macOS, Linux, an iPad or an Android tablet, and installs as an app if you want it in the dock. It is made for the architect, engineer, surveyor or estimator working on their own rather than for a firm buying seats.
What does Redline PDF cost?
Redline Free costs nothing and covers review markup, reading the markups already in a PDF, up to 3 saved drawings and flattened PDF export. Redline Plus is $9 a month or $90 a year and adds clean and editable PDF exports, printing, page tools, the markup summary, revision comparison and calibrated length and area, with up to 25 drawings. Redline Pro is $15 a month or $150 a year and adds full quantity takeoff, building objects, CSV, estimates and unlimited saved drawings. Every account starts with 30 days of Pro, no card.
Does Redline PDF work on a Mac or an iPad?
Yes. It is a browser workspace, so the same tools run on macOS, iPadOS, Windows, Linux and Android tablets, with touch: one finger draws with a tool in hand, two fingers pinch to zoom and move. Nothing about it is Windows-only.
Can Redline PDF measure quantities from a drawing?
Yes, once the sheet is calibrated. Calibrate each page against a printed dimension or scale bar, then measure lengths, areas, perimeters, volumes, angles, radii and counts, take deductions for openings, group measurements by subject, and export the totals as CSV or as a markup summary. A measurement is exact arithmetic on the points you place, at the scale you set.
What can Redline PDF not do?
It has no shared live sessions: drawings belong to one account, and reviews are exchanged as files rather than through a server other people sign in to. It does not read scanned sheets with OCR, so text on a scan stays a picture. It does not shape complex scripts such as Arabic or Indic text in its own text tool. Files are accepted up to 300 MB.
Who is behind Redline PDF?
Redline PDF is operated from the United Arab Emirates, and support runs through support@redline-services.net. Payments and invoices are handled by Paddle as merchant of record. There are no investors and no sales team; the product is paid for by the people who use it.
Try it on the sample drawing
Redline runs in the browser — nothing to install. Open the demo to try tools on a sample drawing. Demo edits are temporary; your own files, saving, signatures, exporting, printing and downloads come with an account, which starts with 30 days of Pro, no card. Then Free unless you choose Plus or Pro; your drawings stay. Plus is $9 a month or $90 a year; Pro is $15 a month or $150 a year. Compare the plans.
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