In the present study, a one-dimensional model is proposed to estimate the pressure drop and heat transfer coefficient for flow boiling in a rectangular microchannel. The present work takes into account the pressure fluctuations caused due to the confined bubble growth and the effect of pressure fluctuations on the heat transfer characteristics. The heat transfer model considers five zones, namely, liquid slug, partially confined bubble, fully confined (elongated) bubble, partial dryout and full dryout. The model incorporates the thinning of liquid film due to shear stress at liquid-vapour interface in addition to evaporation. The transient fluctuations in pressure and heat transfer coefficient, along with the time-averaged ones, are verified with the experimental data available in the literature. Heat transfer characteristics with flow reversal caused by inlet compressibility are also presented. (C) 2019 Elsevier Ltd. All rights reserved.