Both approach wedges and pitching wedges are designed to help golfers land on the green close to the hole. The clubs are designed to be used from different distances. Many golfers carry both in their bag, though the 14-club limit adhered to by the United States Golf Association means that some may have to choose between them.
Pitching Wedge Basics
Golfers use pitching wedges when they're too close to use a longer iron but far enough away that a shorter wedge won't get them near enough to the hole -- generally anywhere from 90 to 110 yards for recreational male golfers. It also works for bump-and-run shots closer to the hole. Over the years, manufacturers have decreased the loft of pitching wedges, and since the sand wedge loft has remained fixed, the gap between the two has increased.
Approach wedges, also commonly called gap wedges, were developed to fill the void between the pitching wedge and the sand wedge. They’re generally used for shots between 70 and 90 yards from the green, or when a sand wedge shot won't reach the green. Some manufacturers include the approach wedge in a standard set of irons, but they also make gap wedges designed like sand wedges labeled with the loft angle, allowing golfers to pick the one that best fills the void between the wedges in their particular set.
Loft and Bounce
Pitching wedges have a loft of between 46 and 48 degrees. Approach wedges have lofts between 50 and 52 degrees. The extra loft on the approach wedge helps it to get up in the air, but decreases the distance hit. Pitching wedges also tend to have a lower degree of bounce than gap wedges. That makes them good options on the fairway, but the higher bounce of a gap wedge is useful when hitting out of the rough.
The 14-club limit means golfers must decide how many wedges to place in their bag. Golfers commonly decide whether to carry three or four wedges, with the pitching, gap and sand wedges considered the most essential for the average golfer. The lob wedge is a specialty club that better players find essential for their games.