To calculate the ROI of your Conversion Rate Optimization (CRO) services, compare the revenue generated from improved conversions against the cost invested.  CRO services ROI = (Revenue from CRO-CRO costs)/CRO costs *100 For instance, let’s assume the improvised strategy leads to an additional $100,000 in revenue for an additional cost of $20,000. Per the formula, the ROI achieved would be  (100,000-20,000)/20,000 *100 = 400% So, the ROI in this case would be 400%. In simpler terms, for every $1 spent, the strategy managed to yield $4.