Spin–orbit torques (SOT) allow ultrafast, energy-efficient toggling of magnetization state by an in-plane charge current for applications such as magnetic random-access memory (SOT-MRAM). Tailoring the SOT vector comprising of antidamping (T$_{AD}$) and fieldlike (T$_{FL}$) torques could lead to faster, more reliable, and low-power SOT-MRAM. Here, we establish a method to quantify the longitudinal (T$_{AD}$) and transverse (T$_{FL}$) components of the SOT vector and its efficiency χ$_{AD}$ and χ$_{FL}$, respectively, in nanoscale three-terminal SOT magnetic tunnel junctions (SOT-MTJ). Modulation of nucleation or switching field (BSF) for magnetization reversal by SOT effective fields (BSOT) leads to the modification of SOT-MTJ hysteresis loop behavior from which χ$_{AD}$ and χ$_{FL}$ are quantified. Surprisingly, in nanoscale W/CoFeB SOT-MTJ, we find χ$_{FL}$ to be (i) twice as large as χ$_{AD}$ and (ii) 6 times as large as χ$_{FL}$ in micrometer-sized W/CoFeB Hall-bar devices. Our quantification is supported by micromagnetic and macrospin simulations which reproduce experimental SOT-MTJ Stoner–Wohlfarth astroid behavior only for χ$_{FL}$ > χ$_{AD}$. Additionally, from the threshold current for current-induced magnetization switching with a transverse magnetic field, we show that in SOT-MTJ, TFL plays a more prominent role in magnetization dynamics than T$_{AD}$. Due to SOT-MRAM geometry and nanodimensionality, the potential role of nonlocal spin Hall spin current accumulated adjacent to the SOT-MTJ in the mediation of T$_{FL}$ and χ$_{FL}$ amplification merits to be explored.