That's what a retirement calculator attempts to do. The amount you will need to save each year to reach your retirement goal. Retirement calculators may vary the approach in answering these questions, but ultimately these are the predictions you need.
Retirement calculators are a valuable tool.
The better ones require a considerable amount of information. However, just because you have provided a lot of information does not guarantee a good prediction. Like many tools, retirement calculators have their limitations. Both predictions involve long periods of time. This makes the prediction very sensitive to factors which must be assumed.