This is a magic portal that can provide hours of entertainment:

Compound Interest

http://www.moneychimp.com/calculator/compound_interest_calculator.htm

This can be another fun calculator if you are trying to have an idea of what your tax return may be:
nerdwallet.com/taxes/tax-calculator

Soon I’ll try to post something about the budget template I am using on regular basis with my family and one rental property.