Family Tree Analyzer is a portable free tool which can analyse a family tree (in GEDCOM form) and produce various reports on it.
You'll first need to save your data in the GEDCOM format. If you're using family tree software then you can probably do that via a Save or Export option. If your tree is on the web, then check the site for export features (at Ancestry, select Tree Pages > Tree Settings > Export Tree).
Launch Family Tree Analyzer, click File > Open and select your GEDCOM file. The program will then import and parse your data (previous versions displayed plenty of errors, but the process is now mostly fault-free), before presenting its analysis under various tabs.
The "Individuals" tab just lists everyone in their tree, along with some core details, for instance. It's very basic, as reports go, but can still be useful. You can sort by any field, for example, ordering the list by surname, birth date, death location and more.
The "Locations" tab displays the various places referenced in the tree (residences, places of birth and so on). Double-clicking any of these displays the related person, handy if you've forgotten who it was who died in Australia (or wherever). And if you need more detail then there are buttons to highlight any location on Google or Bing maps.
The Data Errors tab runs some basic sanity checks on your data. Was an individual born or married after their death, or buried before it? Do you have facts dated before they were born? Did they live to be more than 120? There are 20 checks along these lines, you can choose what you want to run, and the program will highlight any problems for you.
Other reports just aim to help you with your research. For example, the "War Dead" tab highlights males who don't currently have a death date, but were of a likely fighting age during both World Wars, just as a reminder to check the military records. While the Census tab highlights everyone in your list that you'd expect to be alive at a particular census date, but aren't currently recorded, perhaps useful when you're deciding where to look next.
The Geocoder is a particular highlight, a tool which scans the locations in your GEDCOM file, converts them to latitude and longitude, and can display them on various maps. Perhaps best of all, a Timeline view can show you how these locations change over the years as your family move around, an excellent idea which could reveal patterns you'd never noticed before.
Added Report to show a count of relatives of each type
Added BMD searching for Ancestry, FindMyPast and FamilySearch from BMD Colour Report - Double click a birth, marriage or death on the colour BMD form to auto search the web for that entry. Similar to how the census searching works.
Added Option to display females with unknown surname in brackets as unknown
Set search dropdown on BMDs to FreeBMD rather than FreeCen
The interface is basic, and some reports are limited, but Family Tree Analyzer provides a stack of great ways to view, analyze and check your family history data