The calculation of accurate photoelectron spectra (PES) for strong-field laser-atom experiments is a demanding computational task, even in single-active-electron approximation. The Qprop code, published in 2006, has been extended in 2016 in order to provide the possibility to calculate PES using the so-called t-SURFF approach [Tao and Scrinzi (2012)]. In t-SURFF, the flux through a surface while the laser is on is monitored. Calculating PES from this flux through a surface enclosing a relatively small computational grid is much more efficient than calculating it from the widely spread wavefunction at the end of the laser pulse on a much larger grid. However, the smaller the minimum photoelectron energy of interest is, the more post-propagation after the actual laser pulse is necessary. This drawback of t-SURFF has been overcome by Morales et al. [Morales et al. (2016)] by noticing that the propagation of the wavefunction from the end of the laser pulse to infinity can be performed very efficiently in a single step. In this work, we introduce Qprop 3.0, in which this single-step post-propagation (dubbed i-SURFV) is added. Examples, illustrating the new feature, are discussed. A few other improvements, concerning mainly the parameter files, are also explained. NEW VERSION PROGRAM SUMMARYProgram Title: QpropProgram Files doi:http://dx.doi.org/10.17632/cxj2ygn4ph.2Licensing provisions: GNU General Public License, version 3Programming language: C++External routines/libraries: GNU Scientific Library, Open MPI (optional).Journal reference of previous version: Comput. Phys. Comm. 207(2016) 452–463Does the new version supersede the previous version?: Fully supports the functionality of Qprop 2.0.Nature of problem: Efficient calculation of PES for typical strong-field and attosecond physics ionization scenarios.Solution method: The time-dependent Schrödinger equation is solved by propagating the electronic wavefunction using a Crank–Nicolson propagator. The wavefunction is represented by an expansion in spherical harmonics. The t-SURFF method in combination with i-SURFV is used to calculate PES.Reasons for the new version: The i-SURFV method is employed to speed up the calculation of PES.Summary of revisions: The i-SURFV method is implemented. A set of examples is provided.Additional comments including restrictions and unusual features: The atomic potential needs to be of finite range in case of t-SURFF/i-SURFV usage (i.e., the Coulomb tail is truncated at sufficiently large distances). The laser–matter interaction is described in dipole approximation and velocity gauge.For additional information see www.qprop.de