It took 60-90 minutes when we stopped at HNL on a SYD-LAX flight. But what cause most of the delay is that the fuel stop was not planned in advance (Fog at LAX and the primary alternate) and we actually flew past Hawaii and had to double back 1000 miles. I think we arrived about 5 hours late. Late enough that we ended up in hotel before catching a flight to IAD the next day.