Vocal Range Question

I'm trying to get in to singing, and recently I tried to find my vocal range. However I was a bit confused, because according to my piano, I was hitting really low notes like G1 with ease, which from what I can tell is really uncommon. I have a fairly deep speaking voice, but it still seems odd. I learned theres both pitch which is how low/high it is, but theres also tone. So I was wondering, how do I know if you're singing in the right octave?