Use Inspect Element To Test Title Tag Length
Just discovered this the other day and wanted to share. Want to be extra sure that your title tag is going to look right in Google results? Try this quick hack that only requires a browser (a real browser, not Edge).
Notice how, in the gif below, that Google will truncate and add ellipses dynamically if the title tag changes in the DOM. Obviously this is not the tool to use for a large number of titles, but if you have a few really important URLs you want to test, this is probably the most accurate way.