Valuating a business is not a simple task because the number you have in mind may not be the value that your family successors, potential buyers or tax assessors would arrive at. It's probably best to call in a specialist who can look at your assets, liabilities and goodwill with clear-eyed detachment.

To be able to deal with the situation, you should at least become aware of the different methods that can be used to arrive at your business valuation. Once you have that number, you may be able to find ways to improve the value of your existing business.

Valuation methods
There are a number of methods used to valuate a business and they can be used alone or in combination.

Asset-based approach: totals up all investments made in the business to-date. However, this does not account for the depreciation in the value of machinery that may be several years old, or other assets that have declined in value.

Business comparison: when a company's market value is examined, it is compared to similar companies in the field and transactions that have occurred in the recent past. For a very specialized business however, it may be difficult to research comparable transactions. 

Company's past earnings: can be used to calculate a price but those earnings are not a guarantee of future growth.