The Large White can be confused with the Small White (Pieris rapae) but besides being larger, the black patch on the tip of the wing of the Large White spreads to about half way down the wing margin whereas on the Small White it spreads only a short distance.
As with the Small Whites and Green-veined Whites (Pieris napi), males have a single spot (often no spot at all) on the upperwing while females have two.
Top & Left: Boekel area, The Netherlands, 6 July 2018
Middle: In my yard, Hilversum, The Netherlands, 1 July 2017
Right: 's Graveland, The Netherlands, 28 August 2012
Last: In the company of a Large Chequered Skipper. De Groote Peel National Park, The Netherlands, 11 July 2018