For the first time, we report large-area (16 cm2) independently certified efficient single perovskite solar cells (PSCs) by overcoming two challenges associated with large-area perovskite solar cells. The first challenge of realizing a homogeneous and densely packed perovskite film over a large area is overcome by using an antisolvent spraying process. The second challenge of removing the series resistance limitation of transparent conductor is overcome by incorporating a metal grid designed using a semidistributed diode model. A 16 cm2 perovskite solar device at the cell level rather than at the module level is demonstrated using the modified solution process in conjunction with the use of a metal grid. The cell is independently certified to be 12.1% efficient. This work paves the way toward highly efficient and large perovskite cells without single-junction perovskite solar cells and silicon–perovskite tandems.