Estimate from complete rounds
Choose Handicap Index estimate and enter the most recent acceptable 18-hole records, in chronological order. Use the adjusted gross score after the applicable hole-score limits, the Course Rating and Slope Rating for the tees played, and the published PCC for that day. A blank value is not treated as zero.
The tool calculates each Score Differential as 113 ÷ Slope × (adjusted gross score − Course Rating − PCC), then rounds it to one decimal. For example, score 90, rating 72.0, slope 113 and PCC 0 produces 18.0. With slope 130 the same figures produce 15.6, reflecting the different course difficulty.
Which rounds count?
For 3 records the lowest differential is used minus 2.0; for 4, the lowest minus 1.0; for 5, the lowest with no adjustment. With 6 records the lowest 2 are averaged minus 1.0. Thereafter the count is: 7–8 → 2; 9–11 → 3; 12–14 → 4; 15–16 → 5; 17–18 → 6; 19 → 7; 20 → 8.
The result table identifies exactly which rounds count. An average of the selected differentials is adjusted for record count and rounded to one decimal, with a maximum of 54.0. Three differentials of 15.3, 15.2 and 16.6 produce 13.2. The historical 0.96 multiplier is not used.
Convert an existing Index
Choose Course Handicap and enter your Index and the 18-hole rating, slope and par of the tees you will play. The calculation is Index × Slope ÷ 113 + (Course Rating − par). The result is rounded to a whole number; the unrounded figure is also shown.
Index 10.0, slope 113, rating 72.0 and par 72 gives Course Handicap 10. A plus Index of +2.4 is represented internally as −2.4 and gives a plus Course Handicap of +2 for those tees. Competition allowances are not applied.
Understand the estimate
An official Index also depends on an authorized scoring record, exceptional-score reductions, Low Handicap Index safeguards and committee decisions. Those adjustments cannot be reconstructed from these inputs. This page returns the basic record calculation, not a replacement for your association’s official Index.
Nine-hole and incomplete rounds require additional rules and expected-score information; they are not supported here. Use only complete 18-hole rounds. All half-way rounding moves toward positive infinity: a differential of −1.55 becomes −1.5. Input ranges shown above are supported software limits, not a definition of every legally possible score.
Use Copy result to save the estimate, counted rounds and its limits in your notes. Keep the original round records separately: this page does not save a scoring history. Editing a field or adding a round clears the earlier result, so calculate again before copying. A dot or comma may separate a decimal; do not enter thousands separators, units or scientific notation. For an error, correct the named field in the named round without deleting the other records.
R&A · Rule 5 · R&A · Rule 6 · USGA · Course Handicap
Frequently asked questions
Can I calculate from one round?
You can inspect a round’s formula, but an Index estimate here needs at least three complete 18-hole records.
Is my raw score sufficient?
No. Supply the adjusted gross score after the applicable hole-score limits. This tool does not calculate those limits hole by hole.
What if I do not know PCC?
Obtain the official PCC for the course and day. Zero is common, but do not substitute it for a known nonzero adjustment.
Is this my official handicap?
No. Use your authorized association’s record for an official Index and competition requirements.