How can I work out time difference between git tag and the original commit
<p>I am looking to work out the time difference between when a commit is made and when that commit was tagged.</p>

<p>This is what I have so far however the committerdate which I think this is the correct field is null. </p>

<pre><code>git for-each-ref --format='%(taggerdate) : %(committerdate) :  %(refname)' --sort=-taggerdate --count=10 refs/tags
</code></pre>

<p>At a guess I am looking only at tags, though I cannot get it right. In an ideal world it would show the difference between the times however I can do this afterwards if it is not possible.</p>