Three-dimensional write field distributions of trailing-edge shielded and unshielded perpendicular write heads with applied direct current write currents were studied by magnetic force microscopy (MFM) measurements. A quantitative MFM approach of two times integrating measured frequency shift at a series of tip scan heights over the perpendicular direction was proposed to measure the magnetic field strength and field gradient. Results indicate shielded heads in addition to smaller saturation write currents, exhibited more than two to three times higher write field gradients over a wide range of moderate field strength over unshielded heads, thus, producing sharper bit transition and improved signal to noise ratio as theoretically predicted.