What is a handicap?
Your handicap is a measure of your playing ability. The number roughly shows how many strokes over par you need on a course of average difficulty. A player with a handicap of 18 needs about 18 strokes over par on such a course, so roughly one bogey per hole. Beginners start with a handicap of 54, the highest handicap there is.
World Handicap System
Since 2020 the Netherlands has used the World Handicap System (WHS). Your official handicap is called the Handicap Index. It is calculated from the average of your 8 best score differentials from your last 20 qualifying rounds. After every new qualifying round your Handicap Index is recalculated.
Course handicap and playing handicap
Every course is different. That is why you convert your Handicap Index into a course handicap: the number of strokes you receive on that course, from that tee. The slope rating and course rating of the course are taken into account. On a difficult course you receive more strokes than on an easy one. Your playing handicap is the number of strokes you actually receive in a competition. It can be lower than your course handicap, for example in team formats such as a greensome, foursomes and a scramble.
How do the extra strokes work?
The strokes you receive are spread over the holes according to the stroke index on the scorecard. The hole with stroke index 1 is the first to get an extra stroke. With a playing handicap of 18 you receive one extra stroke on every hole. Your gross score minus your extra strokes is your net score.
Protection against big jumps
The WHS limits how fast your handicap can rise. If your Handicap Index rises more than 3 strokes above your lowest index of the past year, the increase is slowed down. A rise of more than 5 strokes is not possible. This way a bad spell does not immediately lead to a much higher handicap.