Sensing voltage based on a supplied to magneto-resistive random access memory (MRAM) bit cells in an MRAM for tracking write operations. Sensing voltage based on supply voltage applied to an MRAM bit cell in a write operation can be used to detect completion of magnetic tunnel junction (MTJ) switching in an MRAM bit cell to terminate the write operation to reduce power and write times. In exemplary aspects provided herein, reference and write operation voltages sensed from the MRAM bit cell in response to the write operation are compared to each other to detect completion of MTJ switching of voltage based on the supply voltage applied to the MRAM bit cell regardless of whether the write operation is logic ‘0’ or logic ‘1’ write operation. This provides a higher sensing margin, because the change in MTJ resistance after MTJ switching completion is larger at the supply voltage rail.