Many PDF and construction tools can compare two revisions of a drawing, but they do it in three different ways. Overlay tools (Bluebeam Revu, Drawboard Projects, Procore, Autodesk Build, Fieldwire, Revizto, Xodo PDF Studio, Ncored) draw both revisions on top of each other in two colours, which is the clearest view for drawings. Report tools (Adobe Acrobat Pro, Foxit PDF Editor, PDF-XChange Editor Plus, Draftable, Nitro) produce a document that lists or highlights the differences, which suits specifications and contracts. The colours are not standardised: in one tool red means removed, in another it means "only on the second sheet". Always read the legend.
Which tools compare drawing revisions, and how?
Prices are list prices seen on each vendor's own site on 22 October 2026, per user, and change often. Check them before you buy.
| Tool | How it compares | Alignment | Runs on | Which plan, list price |
|---|---|---|---|---|
| Adobe Acrobat Pro | Report: a results document with a summary page, side-by-side view and filters; drawings and scans are compared as images | None documented | Windows, Mac | Pro only (not Standard): US$19.99/month on an annual plan |
| Bluebeam Revu | Overlay Pages (each file on its own coloured layer, merged into a new PDF) and Compare Documents (differences marked with clouds in a new PDF) | Page, automatic, or manual on three points | Windows | Core and above: from US$330/year (Basics has no compare) |
| Drawboard Projects | Overlay, each revision in its own colour, more than two revisions at once | Manual (position, scale, 90° rotation) | Windows, iPad/iOS, web (Mac via web) | All plans: Team from US$270/year |
| Procore Drawings | Overlay; a whole set can be compared against its previous revisions | Manual realign on mobile | Web, iOS, Android | Part of Procore, priced by quote |
| Autodesk Build / Docs | Overlay in red and blue, plus a side-by-side mode without colours | Manual | Web, iOS, Android | Part of Autodesk Construction Cloud plans |
| Fieldwire | Overlay: differences in red and blue, matching content in grey; export as an image | Manual (prompted first) | Web, iOS, Android | Pro and above: US$39/month billed annually |
| Revizto | Overlay with a transparency slider, or one sheet at a time | Manual | Revizto apps (cloud projects only) | Priced by quote |
| Xodo PDF Studio | Overlay of two or more documents in contrasting colours | Three points, plus offset, rotation and scale | Windows, Mac, Linux | US$240 one-time per user (2 devices), or from US$9.99/month billed yearly |
| Foxit PDF Editor | Report: old and new side by side with a summary and legend; colours can be set | None documented | Windows, Mac | PDF Editor from US$129.99/year (monthly billing from US$10.99) |
| PDF-XChange Editor Plus | Report: side-by-side results with a list of text, image and annotation differences; no overlay | None | Windows | Editor Plus US$79 one-time |
| Nitro PDF | Windows: text compare and a visual (pixel) compare. Mac: text compare with a summary report | None documented | Windows, Mac | See vendor |
| Draftable | Side-by-side text compare with a change list; scans through OCR; built for text documents rather than drawings | Not applicable | Windows desktop (plus a free web version) | From US$129 per user per year |
| Ncored | Overlay: added in blue, removed in red, unchanged in grey, with a slider that fades the grey; whole sets paired by how the pages look | None (pages laid from the same corner; a half-size print is scaled to fit) | Windows, Mac | €12.99/month, €79.99/year or €159 one-time |
Free online compare tools (Xodo, iLovePDF, PDF24, for example) also exist. Most process files on their own servers and some cap daily use or file size, so check whether client drawings may leave your office before using one.
What do the colours mean in each tool?
There is no shared convention. Some tools colour by what happened (added, removed), others by which file a line came from, and which file counts as "first" depends on the order you load them.
| Tool | Colours, as documented by the vendor |
|---|---|
| Ncored | Blue = added in the open (newer) file, red = removed, grey = unchanged |
| Procore | Red = removed, blue = added (its comparison tutorial; a separate FAQ page describes additions in green) |
| Fieldwire | Red = first sheet, blue = second sheet, grey = matching content |
| Revizto | Blue = only on the first sheet, red = only on the second, black = on both |
| Bluebeam Revu (Overlay Pages) | A colour per file, assigned automatically (red and green by default) and changeable |
| Autodesk Build / Docs | Differences in red and blue (the help does not say which is which) |
| Nitro PDF (Mac) | Yellow = replaced text, blue = inserted, red = deleted |
| AutoCAD DWG Compare (DWG files, for context) | Green = only in the current drawing, red = only in the compared drawing, grey = common (defaults, changeable) |
The practical rule: before you read a comparison, find the legend and check which file you loaded first. "Red" can mean the opposite thing in two tools on the same desk.
Overlay or report: which do you need?
- Plans, sections and details from CAD or BIM: an overlay. One look shows where the geometry changed.
- Specifications, contracts, reports: a report or text compare. It lists inserted and deleted words, which an overlay cannot do on reflowed text.
- Scans: a tool with manual alignment (three points or more), and expect noise. A native PDF from the author is always better.
- Whole sets of hundreds of sheets: look for automatic page pairing or batch compare, otherwise you pair sheets one by one.
For the review workflow around the comparison, see how to review a revised drawing set.
What should you check before choosing a tool?
- Does it overlay, or only report? For drawings, an overlay saves the most time.
- Can it handle different page sizes? Procore and Fieldwire state that their compare needs sheets of the same size; other tools compare them but mark everything.
- Can it align? Manual alignment rescues shifted exports and scans.
- Does it pair whole sets automatically?
- Where do the files go? Desktop tools compare locally; web platforms and online sites process files on their servers.
- Which plan includes it? Compare is often missing from the cheapest tier (Acrobat Standard, Bluebeam Basics).
Where Ncored fits
We built Ncored in our architecture studio as a desktop PDF editor for large drawing sets from AutoCAD, Revit, and ArchiCAD, on Windows and Mac. Its compare is an overlay: open the newer revision, drag the older PDF onto it (or use the Compare button), and read blue for added, red for removed, grey for unchanged. Pages of a whole set are paired by how they look, so an inserted sheet does not shift the rest, and nothing is uploaded or written into either file. It has no alignment tool, no change list and no report document, so for shifted scans or text-heavy documents another tool from the table may suit you better.
Frequently asked questions
What is the best way to compare two drawing revisions?
An overlay, where both revisions are drawn on top of each other in two colours, shows geometric changes on drawings most clearly. Use a text or report compare for specifications.
Does Adobe Acrobat have an overlay compare?
Acrobat Pro's Compare Files produces a report with a side-by-side view. For drawings and scans it compares page images, but it does not draw the two revisions as a coloured overlay.
Which Bluebeam plan includes Overlay and Compare?
Core, Complete and Max. The Basics plan does not include them.
Is there a free way to compare PDF drawings?
Online compare sites are free within limits, but they upload your files. Most desktop tools with an overlay are paid, often with a free trial.
Why does red mean different things in different tools?
Some tools colour by change type (added, removed) and others by source file (first, second). Always check the legend and the order in which you loaded the files.
Related: why a drawing comparison shows everything as changed, how to compare drawings in Adobe Acrobat, how to compare two PDF files for differences.
All product names, logos and brands mentioned on this page are trademarks or registered trademarks of their respective owners and are used for identification only. Ncored is an independent product by Noir architects and is not affiliated with, sponsored by, or endorsed by any of the companies mentioned. Prices as seen on vendor websites on 22 October 2026; verify current pricing on each vendor's own site. Individual experiences may vary.