Tracking capacity

For free and reliable, how about a Google calendar?

You can inspect how that works, and adapt your processes if necessary.

I never track PTO or vacation. Instead, I coach teams to forecast their capacity during Product Backlog refinement, and to reflect this in the future plans.

Thanks @Simon Mayer , I have used Google calendar before and it works well for some of the time, but I am looking for something that will allow teams to enter, but lock it down after a certain cutoff date - like after I've done my capacity planning for the sprint.

@Ian Mitchell  - Thank you for your reply.  I need to be able to forecast capacity and report out. The teams are new and remote with some devs in California and testers in India.  I would like to coach the team to do there own capacity planning, but I need a more immediate solution. 

Ken, I missed the point of what you were trying to do.

My suggestion was for the team to use it to understand their own capacity planning, simply as a means for them to forecast what can be done in upcoming Sprints.

What are you trying to achieve with it? Capacity calculations have little value in themselves. It is probably better to have the Development Team forecast what can be done within a Sprint, and the Product Owner forecast likely completion dates, based on empirical data (of which capacity is just one small aspect).

Beyond that, I see no reason for anyone outside of a self-organizing team to care about capacity.

I'd like to upvote the suggestions made by Ian and Simon, as this is the right way to do it.

However, I'd like to mention I understand where Ken's coming from. This doesn't qualify as free, Ken, but quality has a price: I've found Confluence's calendar tools to be quite useful, so, if you have $10/month to spare (note the number of users), you could sign up and give it a spin. 

I have used capacity planning as tool for new teams.  Basically use it as a plan-but-verify tool.  In the beginning capacity planning is something familiar. But in Scrum it isn't really suggested.  I have the teams start forecasting what they can get done.  Then use their capacity to help them "verify" their forecast.  At the end, I use the same capacity for them to "verify" that the forecasted correctly.  Eventually they will get to a point where they quit using capacity because they have confidence in their forecasts. 

I understand your reasons for doing this but in the end, I would highly suggest you quit doing it as soon as you can.  A Scrum Team should be measured on the consistency of value delivery.  Capacity planning always leads to measuring the amount of hours you are working. 

But if you must do it, I am pretty sure that most of the Agile Tools have some way to track hours.  You could use that as way for people to enter vacation.  I would also assume you have some kind of corporate calendar system. Another way that some of my teams will notify others of their being out is to send out an all day meeting request to the entire team but have it show as being available.  That way the team members can have it on their calendar but it doesn't block their calendars.

Just noticed that I neglected to second that @Ian and @Simon are spot on with their suggestions.