The

**internal growth rate (IGR)**of a business is the highest level of growth achievable for the business without obtaining outside financing. The formula to calculate IGR is as follows:**Internal growth rate (IGR)**= Retention Rate * Return on Assets

where

*retention rate*is the percentage of earnings that a company reinvests and*return on assets (ROA)*is the ratio of annual net income to average total assets of a business during a financial year.To find the internal growth rate (IGR) for a given business, simply enter the retention rate and return on assets in the boxes below and then click the “Calculate” button.