GolfCalc
Handicap index, club gapping, slope adjustment, putting break, and swing speed analysis. Lower your scores with better data.
Handicap Index Estimator
Estimate your handicap index from recent scores using the WHS formula.
Club Distance Gapping
Analyze distance gaps between clubs to find holes in your bag.
Course Handicap (Slope Adjustment)
Convert your handicap index to a course handicap for any course.
Putting Break Estimator
Estimate how much a putt will break based on slope and distance.
Swing Speed to Distance
Estimate driving distance from club head speed. Find your efficiency.
About GolfCalc
GolfCalc provides free golf calculators for recreational and competitive golfers. Estimate your handicap index, analyze club distance gaps, adjust for course slope, read putting breaks, and correlate swing speed to distance.
All tools run in your browser. Share calculations via URL — text your foursome or save for the course.
Golf handicap (World Handicap System): a handicap index represents ability on a course of standard difficulty. Score Differential = (Adjusted Gross Score − Course Rating) × (113 / Slope Rating). Your handicap index = average of the best 8 Score Differentials from your most recent 20 rounds × 0.96. Course handicap (what you actually use on a given day) = Handicap Index × (Slope Rating / 113) + (Course Rating − Par).
Distance and ball flight: driving distance depends on club head speed, smash factor (ball speed / club head speed — ideal is 1.48–1.50 for driver), launch angle (optimal is 10–15° for most amateurs), and spin rate (2,000–2,500 RPM for low-spin distance; too much spin creates ballooning). A swing at 90 mph club head speed with 1.49 smash factor delivers 134 mph ball speed; at 12° launch with 2,400 RPM spin, expected carry ≈ 250 yards in neutral conditions.
Course management: strokes gained analysis (developed by Mark Broadie) measures each shot against a PGA Tour benchmark of expected strokes to hole out from that distance and lie. Strokes Gained = expected strokes before shot − expected strokes after shot − 1. A tee shot to 150 yards in the fairway from a par-4 where the average is −0.2 strokes compared to tee position is calculated against published "expected strokes to hole" tables. This is how tour players and caddies identify where shots are actually being lost.
Green reading: break is caused by slope and grain. On smooth bent grass greens, slope is the primary factor. A 1% slope deflects a ball approximately 2–3 inches per 10 feet of putt. For a 20-foot putt across a 2% slope, expect 4–6 inches of break. Grain (grass growing direction) adds or subtracts; putting into the grain ("into the shine") plays faster; putting with the grain ("into the shadow") plays slower.