Golf Handicap Calculator
Estimate a World Handicap System (WHS) style Handicap Index from your recent adjusted gross scores, course ratings, and slope ratings.
How It's Calculated
Formula
\text{Score Differential} = (\text{AGS} - \text{CR} - \text{PCC}) \times \frac{113}{\text{Slope}} \qquad \text{Handicap Index} = \text{avg(lowest }N\text{ differentials)} + \text{adjustment}This calculator estimates a Handicap Index using the World Handicap System's published Rule 5 method: each round's Score Differential is (Adjusted Gross Score − Course Rating − PCC) × (113 ÷ Slope Rating), which normalizes a round to a course of standard difficulty (slope 113). With fewer than 20 scores, an official Rule 5.2a table determines how many of your lowest differentials are averaged and what adjustment is added — for example, with exactly 3 scores, only your single lowest differential is used, with a −2.0 adjustment. Once 20 scores are available, the lowest 8 of the most recent 20 are averaged with no adjustment. The result is rounded to the nearest tenth. This calculator is labeled an ESTIMATE, not an official WHS Handicap Index, because it cannot replicate two parts of the full official calculation: the Playing Conditions Calculation (PCC), a same-day adjustment computed from the entire pool of scores posted at a course (not derivable from one golfer's own scores, so this calculator uses PCC = 0), and Exceptional Score Reduction / soft-and-hard caps, which require tracking a player's Handicap Index history over time as each round is posted in sequence — not just a final batch of scores.
Worked Examples
3 rounds (minimum): lowest 1, adjustment −2.0
- Rounds: AGS 90/CR 72/Slope 113, AGS 95/CR 72/Slope 113, AGS 100/CR 72/Slope 113
- Differentials: (90−72)×113/113=18, (95−72)×113/113=23, (100−72)×113/113=28
- With 3 scores, Rule 5.2a uses the lowest 1 differential and a −2.0 adjustment
- Handicap Index = 18 + (−2.0) = 16.0
20 rounds: lowest 8 of 20, no adjustment
- With 20 scores entered, Rule 5.1 applies: average the 8 lowest differentials
- No net adjustment is added at 20 scores
- The result is rounded to the nearest tenth
Frequently Asked Questions
Is this my official USGA/R&A Handicap Index?
No — treat this as an estimate. It follows the official Rule 5 differential and averaging formulas, but it cannot apply the Playing Conditions Calculation (which needs the full pool of scores posted at your course that day, not just your own) or Exceptional Score Reduction and the soft/hard caps (which require your Handicap Index history over time). Your official Handicap Index, tracked through GHIN or another authorized WHS provider, may differ slightly from this estimate.
Why does this calculator need my most recent scores specifically?
The World Handicap System only ever uses your most recent 20 scores. Enter your rounds oldest-first so the calculator knows which ones are most recent; if you have more than 20, remove your oldest rounds before calculating.
Why is the adjustment negative for 3-6 scores?
With very few scores, the official Rule 5.2a table applies a downward adjustment (as much as −2.0 for just 3 scores) as a conservative safeguard, since a new or thin scoring record is less statistically reliable than a full 20-score history.
What is Slope Rating, and why is it limited to 55-155?
Slope Rating measures how much harder a course plays for a bogey golfer relative to a scratch golfer. The World Handicap System defines its valid range as 55 to 155, with 113 representing a course of standard difficulty — that's why the Score Differential formula divides by Slope and multiplies by 113.
What happens if I enter a score, rating, or slope outside a valid range?
The calculation is not performed, and a message identifies exactly which round and which field is invalid, so your entered data is never silently ignored or replaced.