You can see how long it will take by measuring the shortest layer to the longest and calculating how long it will take if your hair grows half an inch per month. How long it takes will also depend on whether your layers are long or short. If they are short layers, they could take three to six months to grow out completely. If they are long layers, they could take six months to a year. You can help ease the process by getting micro trims that take off the layers little by little.