There isn't any mathematical formula.  The amount of compensation for pain and suffering depends on  the particular case and is based on the information in the medical reports which document the nature and extent of the injury.  For example, someone who has residual complaints of pain will receive more compensation for pain and suffering than someone who has fully recovered.  Someone who has scars from the accident will receive more compensation than someone who does not have scars. Compensation for the medical bills is straight reimbursement.  Compensation for wage loss is straight reimbursement.  Compensation for pain and suffering is an amount in addition to the medical bills.As a starting point in settlement negotiations with the at-fault party's insurance carrier, I would ask for quadruple the medical bills to compensate for pain and suffering, but NOT expecting to get that.  The insurance company will respond with a much lower offer as a starting point in negotiations.  Continue negotiating and try to get the insurance company to increase its offer.  If the case is settled with the at-fault party's insurance carrier, NO lawsuit is filed.  If you are dissatisfied with settlement offers from the at-fault party's insurance carrier, reject the settlement offers and file your lawsuit for negligence against the at-fault party / registered owner of the vehicle (if the registered owner is someone other than the at-fault party).  If the case is NOT settled with the at-fault party's insurance carrier, you will need to file your lawsuit for negligence prior to the expiration of the applicable statute of limitations or you will lose your rights forever in the matter.