Best Microsoft Project Viewers Compared, Free and Paid

The best Microsoft Project viewer depends on three things: what you need to see (a Gantt, links, critical path, baselines, resources), which device you are on, and whether the file may leave your machine. Microsoft's own route is paid: on Microsoft's US pricing pages on September 29, 2026, Planner and Project Plan 3, the subscription that includes the desktop app, was $30.00 per user per month. Several viewers open the same .mpp for nothing.

If you just need to look at a file now, open your .mpp in the free online viewer and come back for the comparison.

In short. For full fidelity use Microsoft Project, which is paid. For a free viewer, Project Plan 365's free viewer lists the most views and platforms, Onplana Schedule adds editing and a Project XML save on Windows, Mac, iPhone, iPad and Android, and ProjectLibre, GanttProject and MOOS Project Viewer run on Windows, Mac and Linux. Whether your file is uploaded varies by tool, so read that line first.

How do we rank the viewers?

The ranking uses four criteria, in this order: fidelity to what Microsoft Project shows, platforms covered, price, and what happens to your file. Every vendor fact below is from the vendor's own page on November 10, 2026, and where a page does not state something, the table says so instead of guessing. Onplana ships two of the seven options, so read its placement against those criteria, not as a recommendation by default.

What are the best Microsoft Project viewers?

1. Microsoft Project. The reference. It opens every .mpp exactly as it was built, with every view. The cost is the point: $30.00 per user per month for Planner and Project Plan 3 on Microsoft's page, or a one-time Project 2024 licence. Windows only for the desktop app; Microsoft Project for Mac covers the Mac situation. What each Microsoft option costs is set out in full.
2. Project Plan 365 free viewer. Its page offers a free viewer for Microsoft Project files on Windows, Mac, iOS and Android, listing Gantt Chart, Calendar, Resource Sheet, Team Planner, Network Diagram, Tracking Gantt and Timeline views, for files from Project 2010 to 2024. That is the widest view list here. Its page does not say whether the free viewer can edit or save, or whether files are uploaded.
3. Onplana Schedule (desktop). Free on Windows 10 (1809) or later and macOS 13 or later. It shows a Gantt and grid with predecessors, resources, percent complete, outline, critical path, float, milestones and baseline bars when the file carries them. It edits with undo, exports a PDF, and saves a new Project XML file beside the original. It does not write .mpp. Onplana Schedule is the app.
4. Onplana Schedule (phone and tablet). The same app on iPhone and iPad (iOS 17.4 or later) and on Android phones and tablets, free, with editing and saving included. It opens .mpp, .mpt, .mpx, .xer and Project XML from Files or the phone's storage. The phone and tablet build has the store links.
5. Onplana's online viewer. Read-only in a browser, with no install and no signup: Gantt, task table, critical path, baseline and resource usage, with a PDF, picture or CSV export. It cannot edit. Files converted on the server can be up to 20 MB.
6. ProjectLibre and GanttProject. Free, open-source desktop apps. ProjectLibre opens .mpp and runs on Windows, macOS and Linux. GanttProject's page says it is free, runs offline on Windows, macOS and Linux and reads MPX, MPP and MSPDI files, though its own notes warn dates can shift on import. The free Microsoft Project alternatives post covers both.
7. MOOS Project Viewer. A paid Java viewer for Windows, Mac OS X and Linux. Its page lists Gantt Chart, Task Usage, Resource Sheet, Resource Usage, Tracking Gantt and Team Planner views and says it shows critical path, deadlines and baselines. Its page does not state a price or where files are processed.

Where Onplana is not the best: Project Plan 365 lists more views, and ProjectLibre, GanttProject and MOOS cover Linux, which Onplana Schedule does not. Where it is strong: editing with a Project XML save, and a phone and tablet build.

How do the viewers compare?

The diagram shows the choice in one picture, and the table below has the detail.

What happens to your file in each viewer?

For Onplana's tools, the file's contents decide, not its extension. If the contents are Microsoft Project XML, the file is read on your machine and nothing is uploaded, except that a health check or a publish uploads a copy. Everything else, a binary .mpp and a Primavera P6 or Planner XML export alike, is converted on Onplana's servers, and the uploaded copy is deleted within 3 days and removed from backups 7 days after that. A ProjectLibre .pod is looked inside first, and if it holds Project XML it is read locally. Both tools ask before each upload. For other vendors, the desktop apps run locally and the pages for Project Plan 365 and MOOS do not say, so ask them before you open a sensitive file. What an MPP file is explains why the format needs a converter at all.

Which viewer should you pick?

Match the tool to the job:

1. One look, no install: the browser viewer, or Project Plan 365's free viewer.
2. Keep working a plan someone sent you: Onplana Schedule, or ProjectLibre if you are on Linux.
3. Exact Microsoft rendering: Microsoft Project.
4. A phone or tablet: Onplana Schedule or Project Plan 365.

The step-by-step is in how to open an MPP file without Microsoft Project, and converting an MPP file to Excel or PDF covers the export routes.

Open your .mpp in the free online viewer Read the Gantt chart, task table and critical path in your browser, with no install and no signup. A Project XML file is read in your browser; any other file is converted on Onplana's servers and deleted within 3 days. → Open the online viewer

Microsoft Project™ is a trademark of Microsoft Corporation. Onplana is not affiliated with Microsoft.