Assign a Planner task to more than one person

Short answer: yes, you can assign one Planner task to several people. The catch is that the task has one status. Microsoft says "When any team member marks the task complete, it's marked complete for all team members." So if each person must finish their own part, give each person their own task, or use a checklist on one task.

What Planner does when you add several assignees

Microsoft's page "Assign people to tasks" says "When a task is being worked on by more than one team member, you can assign it to up to 11 people" so that "they can all see it in their Assigned to me list." Exact names and wording may differ in your version of Planner. Microsoft's Planner limits page lists "Maximum assignees in a task" as 20. The two pages give different numbers, so test in your own plan before you plan around a limit. Microsoft's Planner limits page lists "Maximum assignees in a task" as 20. The two pages give different numbers, so test in your own plan before you plan around a limit.

That gives you two facts to plan around:

A task can have more than one person on it, up to the limit Microsoft states.
The task has one shared finish line. One person marking it complete closes it for everyone.

An answer on Microsoft Q&A says it this way: "if you assign a task to different people in the Planner app when one person marks it as done, it will be marked as done for all." The same answer adds "Currently, it is not possible to set it up individually unless you create the same task and share it with each individual." Features change, so check the Planner pages from Microsoft for the current state.

Decide first: one shared job or many separate jobs

Before you add names, ask one question: does the job need to be done once, or once per person?

One shared job. Example: "Book the room for the Friday meeting." Any one person can do it, and the others only need to know it is covered. Put everyone who should see it on the task. The first person to finish marks it complete.

Many separate jobs. Example: "Each member sends in a signed form." Five people must each finish. One shared task will not show who is done, because the first person to mark it complete closes it for the other four. This is the case that causes trouble.

Option 1. One task per person

This is the clearest way to track each person. It is one way to start.

Open Planner at https://planner.cloud.microsoft and open your plan.
Create the task once. Give it a clear name, a due date and any notes.
Copy the task. Microsoft's page "Copy, cut, paste, and move tasks in Microsoft Planner" lists these steps: "Select or open a single task." and "Open Copy Options under More options (...)." Then choose the plan and bucket, choose which details to include, and select Copy.
In the copy, set the assignee to one person.
Repeat until each person has a task.
Add the person's name to each task title, for example "Send signed form: Member 104". Our advice, not a Microsoft rule: a name in the title makes the board easy to scan.

Microsoft's copy page lists these optional fields: Attachments, Labels, Custom columns, Dates, Status and Assignments. It says "Only members of the destination plan remain assigned." when you copy to a plan in a different group. Check the Include options before you press Copy so you do not copy names you did not mean to copy.

What you get: every person has a task that only they finish. Open the plan and look at which tasks are marked complete to see who is done. Exact names may differ.

Option 2. One task with a checklist

Use this when the parts are small and belong together, such as five short checks on one event.

A Microsoft Q&A answer suggests "creating a checklist with the users' names for the tasks you want them to complete." So the task holds one checklist item per person.

How to set it up:

Make one task, for example "Confirm attendance".
Add a checklist item for each person, such as "Member 104 confirmed".
Each person ticks their own line.
The task owner marks the whole task complete when the last line is ticked.

Limits to know:

Our advice, not a Microsoft rule: treat the name in a checklist line as a label only, and do not count on it to assign the line to a person.
Nothing in the checklist stops one person from ticking another person's line. Our advice, not a Microsoft rule: agree on the habit with your team, and do not use this for anything that needs proof.
Any assignee can still mark the whole task complete early, because the task has one status.

Option 3. One main task and linked tasks

Our advice, not a Microsoft rule: for larger work, make one task as the parent job, then one task per person for the parts. Put the parent task in its own bucket named "Parent jobs". Put the person tasks in a bucket named by the job. The parent holds the due date and the description. The person tasks hold the real work. You close the parent when all the person tasks are done.

This costs more setup, but it answers two questions at once: "is the whole job done" and "who is still holding it".

Option 4. When Planner is the wrong tool

If you need a status per person, a due date per person, and a clear list of who has not finished, a list may fit better than a task board. One row per person per job gives you a column for each of those. See "Microsoft Planner vs SharePoint List: Which Should Your Team Use?". Our advice, not a Microsoft rule: for a few such jobs Planner is fine, and for a long run of them a list is easier to filter.

Choose a shape for your task names

Names do more work than people expect. One way to start:

Start with the action: "Send", "Book", "Review".
Name the thing: "signed form", "room", "draft".
End with the person or group: "Member 104" or "Front desk team".

A board with names like this reads well without opening each card.

Removing someone from a task or a plan

Removing a person from the plan does not remove their tasks. Microsoft's page says "People removed from a plan will still be able to view and edit tasks assigned to them." and "If you would like to restrict their access, you must unassign them from each task they are assigned to." When someone leaves a project, unassign them from the tasks first, then remove them from the plan.

What to avoid

Do not put five people on a task that needs five finishes. The first person to click complete closes it for all.
Do not rely on the Assigned to me list alone to know who is done. It shows what is assigned, not who has finished their part of a shared task.
Do not use a task title like "Everyone" with no names. Nobody owns it.
Do not plan around a fixed number of assignees. Microsoft's help page says 11 and its limits page says 20. Test in your plan.
Do not copy a task into a different plan and assume the assignees came along. Check the Include options and the plan members.
Do not mix both patterns in one plan without a rule. Pick "one task per person" or "one task with a checklist" and keep to it.

Honest limits

Planner is a simple task board. It is good at showing who has what and what is due. It is not built to track a separate result for each person on one card. If your work needs that, use separate tasks or move the tracking to a list. If notifications do not arrive when you assign people, see "Planner does not email me when a task is assigned". If you need a paid tier for more features, see "Planner Premium or basic Planner for a 10 person team". To create tasks from a form response, see "Create a Planner task automatically from a Forms response".

When to get help

You can build all of this yourself in Microsoft 365. If you would rather have it built and tested for your team, I do that. A tracker like this is a fixed price: $5,000 for one, built in 2 weeks. See "What a SharePoint tracker costs to build". Bring one example of the problem to a free call.

Tell me what's still manual

I am Al Davies. I run 250 High Street LLC and build SharePoint trackers and Power Automate flows for operations teams. I work remotely. The first call is free, and I will not try to sell you anything.

See trackers I built: Tools I built

FAQ

How many people can I assign to one Planner task?

Microsoft's page "Assign people to tasks" says "you can assign it to up to 11 people". Microsoft's Planner limits page lists "Maximum assignees in a task" as 20. Test in your own plan before you rely on either number.

If one person marks the task complete, what happens for the others?

Microsoft says "When any team member marks the task complete, it's marked complete for all team members." Use separate tasks if each person must finish their own.

Can I see which assignee finished their part?

Not on a shared task, because it has one status. A Microsoft Q&A answer says you cannot set this up individually unless you create the same task for each person. A checklist with names can help as a label.

What is the fastest way to make the same task for many people?

Copy the task. Microsoft's copy page lists a Copy Options command under More options. Choose which details to include, then change the assignee on each copy.

Do I need a list instead of Planner?

Only if you need a status and date for each person. For a few shared jobs, separate Planner tasks are enough. For many, a list with one row per person is easier to filter.