After Apollo 1, the Apollo program was put on hold while the accident could be investigated. How long was the program put on hold? How much did it delay the actual Moon landing?
The delay was not only the hold for investigation. More time was needed to design and build a new hatch, to develop a fire proof cloth for the space suits outer layer, to modify the suits and to remove all flammable material from the Command Module and replace it with fire proof material.
Apollo 4 was delayed for about a year:
"Originally planned for late 1966, the flight was delayed to November 9, 1967"