I actually stumbled upon this link, and there are so many calculators (100) that I suggest reviewing the ones that are most applicable and critical to your business. Cash Flow is a good one!

clipped from www.businesscreditcards.com

Business Operations

Don’t get caught off guard by the unexpected financial pitfalls of owning a business. Keep one step ahead with these useful business calculators.

1. Break Even Analysis: Figure out how much you’re going to need to sell with your business just to break even. This can be helpful in creating a starting point for your sales goals.
2. Business Valuation: Whether you are just curious, or want to sell your business, this calculator can help you determine the value. Just enter your cash flow and your expenses to get an estimate.
3. Working Capital Needs: Find out what your business will need to keep going with this helpful calculator. It will take into account your short-term monetary obligations and figure out how much capital you’ll need so you won’t fall short.