This new square is the same size as the Firetruck 40 (which means it begins with 40-windows when using the interlocking technique, chart size of 81 x 81); see more of this size listed here: ashleeslint.com/patterns#large
When using worsted weight yarn and meeting my gauge you should get a finished square of about 20″ / 50cm.
You can create a large border to get a small baby blanket or join it to some more squares and make a blanket! It is easiest to use squares of the same size but you can also mix and match (the Dumptruck 20 square might work with this one?).
The Excavator 40 is available on Ravelry, now! I am not putting it on sale, like I usually do with new patterns, because of my big Designaversary Celebration Sale! (Sale is over now)