Some embodiments an infusion pump system can be used to determine a user's total insulin load (TIL) that provides an accurate indication of the insulin previously delivered to the user's body which has not yet acted. In particular embodiments, the TIL can account for both the bolus deliveries and the basal deliveries that have occurred over a period of time. Such information may be useful, for example, when the infusion pump is operated in conjunction with a continuous glucose monitoring device.