A free Microsoft Project alternative with a real critical path

Microsoft Project answers one question better than a to-do list can: if this task slips a week, does the whole project slip a week? Answering it takes a schedule with dependencies and the critical path method, not a server or a licence. Here is a project planner that does that arithmetic in a browser tab, free and with no account, laid out the way people who have used a desktop planner expect, and a plain list of what it leaves out.

Plan is a project planner in the free Workspace. A task sheet beside a Gantt chart, summary tasks by indenting, milestones, all four link types with lag and lead, constraints and deadlines, a working calendar with holidays, resources with rates, levelling, a baseline to measure slippage against, progress and actual dates, and a network diagram, calendar, timeline and nine reports. The critical path is worked out by the critical path method and drawn in red. It opens and saves the XML format Project reads and writes, and a CSV. There is no account and nothing is uploaded. It does not open .mpp files, count durations in hours, or let several people work on one plan.

What Microsoft Project is good at

Project is the planner most project managers learned on. The desktop program and Microsoft's cloud versions do scheduling, resources and cost in depth, work in hours and minutes as well as days, pool resources across several projects, and, in the cloud versions, let a team update one plan and report against it. It is sold by subscription or licence, and in an organisation that runs its programmes on it, it is the right tool.

Many people who need a Gantt chart are not in that organisation. They are planning a house move, an office relocation, a small build, an event, a thesis, or a piece of client work, and they need the dependencies, the critical path and a chart they can print, once or twice a year, without a licence for it.

What happens here instead

The plan is kept in this browser and the arithmetic runs in the tab. A forward pass gives every task the earliest it can start and finish, a backward pass from the finish gives the latest it can start and finish without moving the end date, and the difference is its slack; the tasks with none are the critical path. Everything is counted in working days and only turned into dates at the end, so a five-day task that starts on a Thursday finishes on the following Wednesday, and nothing lands on a weekend or a holiday. The page works with the network switched off once it has loaded.

Project's features, and which of them are here

Feature	Here	Notes
Gantt chart beside a task sheet	Yes	Drag a bar to move it, its end to change its length, or onto another bar to link them
Critical path and slack	Yes	Shown in red; slack can be drawn as a bar
Summary tasks and milestones	Yes	Indent and outdent to build the outline
Finish-to-start, start-to-start, finish-to-finish, start-to-finish	Yes	With lag and lead
Constraints and deadlines	Yes	As soon as possible, must start on, start no earlier than and the rest
Manually scheduled tasks	Yes
Working calendar with exceptions	Yes	Change Working Time
Work and material resources, rates and units	Yes	Resource Sheet and Assign Resources
Resource levelling	Yes	Level the selection, a resource or everything, and clear it again
Baseline and the Tracking Gantt	Yes	Set, clear, and see the slippage
Progress, actual dates and a status date	Yes	Update Project, Update Tasks, mark on track
Tables: Entry, Schedule, Tracking, Variance, Cost, Work, Summary	Yes
Filters and highlights: critical, late, slipping, milestones	Yes
Network diagram, calendar and timeline views	Yes
Reports	Yes	Project, Cost and Work Overview; Resource Overview; Overallocated Resources; Critical, Late and Slipping Tasks; Milestones
Open and save Project XML	Yes	The exchange format Project itself reads and writes
CSV in and out, the chart as SVG, printing	Yes
Open an .mpp file	Not here	Save it as XML from Project first
Durations in hours and minutes	Not here	A duration here is a whole number of working days
Several projects sharing a resource pool	Not here	One plan at a time
A team updating one plan, timesheets	Not here	No server, so no shared plan

Moving a plan between the two

Project's own .mpp format is not published in a form a browser can read, so it is not opened here. Project also reads and writes an open XML format, the Project Data Interchange schema, and that is the bridge: in Project, save the plan as XML, and open that file in Plan. Tasks, the outline, durations, links with their types and lag, constraints, the calendar and resources come across. Going back, Plan saves the same XML, written in the order the schema sets out so that a reader which checks it accepts it, and Project opens it.

Plan's own file (.plan.json) keeps everything in the plan, and opens here again exactly as it was. A CSV goes to and from any spreadsheet, the Gantt chart saves as an SVG picture that prints and scales cleanly, and the plan prints from File.

What is not here

.mpp files. Save as XML in Project, then open that.
Hours. Every duration is a whole number of working days. A plan that is scheduled by the hour, such as a shutdown or a cut-over weekend, needs a planner that counts hours.
Several projects at once. No master projects, no links between plans, and no resource pool shared across them.
Working together. One person edits a plan. Share it by sending the file, a PDF of the printout, or the chart as a picture.
Macros and add-ins.

What it costs

Nothing. Plan is part of the Workspace, which is free for everyone with no account, with every feature on this page, saving and exporting included. OBSCURA Pro is for the site's single-purpose tools; a plan never needs it.

See a plan working first. Open Plan and start from the example office move to see the critical path, the baseline and the reports on real tasks, or open the XML of a plan you already have.

Questions people ask about A free Microsoft Project alternative with a real critical path

Is there a free alternative to Microsoft Project?

Yes, for planning one project with dependencies. Plan runs in the browser tab, part of the free Workspace, with a Gantt chart, the critical path, all four link types, constraints, a working calendar, resources and levelling, baselines, tracking and reports. There is no account and nothing is uploaded. It does not open .mpp files or schedule in hours.

Can it open Microsoft Project files?

Not .mpp files. It opens the XML format Project also reads and writes: in Project, save the plan as XML and open that here. The tasks, outline, durations, links, constraints, calendar and resources come across, and Plan saves the same format back for Project to open.

Does it show the critical path?

Yes. A forward and a backward pass through the schedule give every task its slack, and the tasks with none are the critical path, drawn in red on the Gantt chart and the network diagram. It is recalculated as you change the plan, and there is a Critical Tasks report and filter.

Can several people work on the same plan?

No. The plan is kept in one browser on one device, and there is no server for anybody else to connect to. Send the file, the XML or a printout instead.

Is it really free?

Yes. Plan is part of the Workspace, which is free for everyone with no account, including saving, exporting and printing. OBSCURA Pro pays for the site's single-purpose tools and is not needed for a plan.