A typical multiplier in a personal injury case is anything from 1.5 times the amount of medical damages to 5 or more times the amount of economic damages.
For example, consider that you have been hurt in a personal injury accident and your medical bills are $10,000. You use a multiplier of 1.5 to arrive at non-economic damages. In that case, you would ask for an additional $15,000 in damages for a total of $25,000 in your case.
If you were to use a multiplier of 5 for the same case, you would ask for $50,000 in non-economic damages if you had $10,000 in damages. The big question is knowing what multiplier to apply. That depends on the exact circumstances of the case. Keep in mind that multipliers on the high end are rare.