how much term insurance is enough?

For a single mom with a 2-year-old, how much term insurance is enough? The dad is not helping anything. My mom is living with me and I would like to cover her as well. We are in the US.

I have about 400,000 coverage from work and some savings. The insurance agent told me I still need an additional 1M. Is that too much? I though we should deduct our savings from the recommended total amount.

Any suggestion? Thank you.