Method for determining an injection pressure (p_erm) for injecting a fuel into a cylinder (3a-d) of an internal combustion engine by means of an injection valve (4a-d), wherein the injection pressure of the fuel is generated by a fuel pump, having the steps: in a first working cycle of the cylinder (3a-d), measuring a first measured injection pressure value (p_gem) of the fuel injected by means of the injection valve (4a-d), and determining a first simulated injection pressure value (p_sim1); in a second working cycle of the cylinder (3a-d), determining a second simulated injection pressure value (p_sim2); determining a difference (Δp_sim) between the first simulated injection pressure value (p_sim1) and the second simulated injection pressure value (p_sim2); and determining an injection pressure (p_erm) for injecting the fuel into the cylinder (3a-d) in the second working cycle by means of the injection valve (4a-d) on the basis of the first measured injection pressure value (p_gem) and the determined difference (Δp_sim) between the first simulated injection pressure value (p_sim1) and the second simulated injection pressure value (p_sim2), wherein the first measured injection pressure value (p_gem) and the first simulated injection pressure value (p_sim1) each correspond to an injection pressure at a first predefined time in the first working cycle, and the second simulated injection pressure value (p_sim2) corresponds to an injection pressure at a second predefined time in the second working cycle, wherein the first time and the second time correspond to each other in such a way that the injection pressure values from the first and second working cycles have been determined under the same or similar conditions. in a first working cycle of the cylinder (3a-d), measuring a first measured injection pressure value (p_gem) of the fuel injected by means of the injection valve (4a-d), and determining a first simulated injection pressure value (p_sim1); in a second working cycle of the cylinder (3a-d), determining a second simulated injection pressure value (p_sim2); determining a difference (Δp_sim) between the first simulated injection pressure value (p_sim1) and the second simulated injection pressure value (p_sim2); and determining an injection pressure (p_erm) for injecting the fuel into the cylinder (3a-d) in the second working cycle by means of the injection valve (4a-d) on the basis of the first measured injection pressure value (p_gem) and the determined difference (Δp_sim) between the first simulated injection pressure value (p_sim1) and the second simulated injection pressure value (p_sim2), wherein the first measured injection pressure value (p_gem) and the first simulated injection pressure value (p_sim1) each correspond to an injection pressure at a first predefined time in the first working cycle, and the second simulated injection pressure value (p_sim2) corresponds to an injection pressure at a second predefined time in the second working cycle, wherein the first time and the second time correspond to each other in such a way that the injection pressure values from the first and second working cycles have been determined under the same or similar conditions.