To better characterize seismic hazard, particularly, for induced seismicity, there is an increasing interest in methods to estimate moment magnitude () for small earthquakes. is generally preferred over other magnitude types, but, it is difficult to estimate for earthquakes with local magnitude () , using conventional moment tensor (MT) inversion. The 2020 5.7 Magna, Utah, seismic sequence provides an opportunity to illustrate and evaluate the value of spectral methods for this purpose. Starting with a high‐quality seismic catalog of 2103 earthquakes (), we estimate using two independent spectral methods—one based on direct waves, yielding , and the other based on coda waves, yielding . For the direct‐wave method, we present a non‐parametric (NP) inversion scheme that solves for apparent geometrical spreading, G(R), and site effects (S), similar to other NP procedures that have been used to calibrate regional scales. The NP inversion is constrained using s derived from MTs for nine events in the Magna sequence. We recover statistically robust and physically reasonable G(R) and S and compute for 635 Magna earthquakes down to 0.7. For the coda‐wave method, we consider two separate calibration schemes involving previous MT solutions and compute for 311 earthquakes down to 1.0. For 280 of the events that were processed with both methods— and —are strongly correlated (r = 0.98), with a mean difference of only 0.05. We compare and with and find reasonably good agreement for with the theoretically predicted relationship of , in which is a regional constant. Our results imply that seismic network operators can use spectral‐based estimates to replace estimates for events with , and possibly smaller. The main requirement is the existence of a small number of MT solutions for calibration purposes.