The formula with 2 substituted
miles = 2 ÷ 1.609344 = 1.243
The constant is an exact definition, not a rounded factor: the mile is 1.609344 km, the US gallon is 3.785411784 litres and the imperial gallon is 4.54609 litres. The Kilometres to Miles Converter explains where each comes from and gives a longer table.
At a walking pace of 5 km/h, 2 km takes about 24 minutes. At an easy running pace of 10 km/h it takes about 12. In metres it is 2,000.
What 2 kilometres means in practice
2 km is 1.24 miles, a distance many charity fun runs and junior parkrun events use because it is short enough for children and long enough to feel like an event. Walking it takes about 24 minutes.