You can just go to their calculator (which I find much better than the AWS one).

Here it is with the 1 year committed use: https://cloud.google.com/products/calculator/#id=79186cdb-18... ($30.82/month)

3 year committed use: https://cloud.google.com/products/calculator/#id=afd446fc-74... ($22.01/month)

And here without: https://cloud.google.com/products/calculator/#id=3ff5d861-75... ($48.92/month)