What is the score differential formula?

The score differential for one round is (adjusted gross score minus Course Rating) times 113 divided by Slope Rating. For example, a round of 85 on a course rated 72.0 with a slope of 113 gives (85 − 72) × 113 ÷ 113 = 13.0. Each differential is rounded to one decimal place, and these per-round numbers are what later get averaged into your Handicap Index.

What are Slope Rating and Course Rating?

Course Rating is the score a scratch golfer is expected to shoot on the course, written like 72.0. Slope Rating measures how much harder the course plays for a bogey golfer than for a scratch one, on a scale from 55 to 155. A tougher layout has a higher slope. For example a course rated 71.5 with a slope of 125 plays harder than the same rating at slope 113, so the same raw score yields a lower differential there.

How many rounds does the WHS use for the index?

The World Handicap System looks at your most recent 20 scores and averages the best 8 differentials. With fewer rounds it uses a sliding table: 3 to 5 rounds count the single best, 6 to 8 count the best 2, 9 to 11 the best 3, and so on up to 20. You need at least 3 acceptable scores before any Handicap Index can be issued, which is why this tool shows nothing until you enter three valid rounds.

Why is 113 in the formula?

113 is the standard Slope Rating, defined as a course of average difficulty under the WHS. When a course has a slope of exactly 113, the multiply-by-113 and divide-by-slope cancel out, so the differential equals the plain difference between your score and the Course Rating. For example a round of 85 on a 72.0 course at slope 113 gives a differential of exactly 13.0. Slopes above 113 lower the differential, slopes below 113 raise it.

What does the ×0.96 do?

After averaging your best differentials, the WHS multiplies the result by 0.96 to produce the Handicap Index. The 0.96 factor, a holdover from the older 96 percent bonus-for-excellence step, slightly favors your better golf and keeps the index from drifting up. For example an average of 4.5 across your best 8 becomes 4.5 × 0.96 = 4.32, which truncates down to a 4.3 index. The system truncates rather than rounds up.

How many rounds do I need to start?

You need at least 3 acceptable 18-hole scores. With exactly 3 rounds the index uses only your single lowest differential minus a built-in adjustment, so early indexes move a lot as you post more cards. The index becomes stable once you reach 20 rounds, where it settles on the best 8 of 20. For example three differentials of 13, 18.1 and 9 take the lowest, 9, giving 9 × 0.96 = 8.6.

Track your Handicap Index between official updates

Your club posts a revised index on the first of the month, but you have played four cards since then. Enter every recent round with its Course Rating and Slope, and the tool shows where your index is trending right now, using the same best-of lookup the official system uses. You walk to the first tee already knowing roughly what strokes you will get.

Compare two courses before booking a trip

You are choosing between two resort layouts. One is rated 72.0 at slope 118, the other 70.5 at slope 132. Punch a realistic score into quick mode for each and read the differential. The harder course converts the same raw round into a lower differential, so you can see which one actually flatters your handicap before you pay for the tee time.

Sanity-check a differential your app reported

A scoring app spit out a differential that looked off. Type the score, Course Rating and Slope into quick mode and check the math yourself: (score minus rating) times 113 divided by slope. If the numbers disagree you know the app used the wrong rating or slope for the tee you played, which is the usual culprit.

Teach a new golfer how the index is built

Explaining the WHS to a beginner is easier with numbers on screen. Add a handful of rounds, point out which differentials the best-of table keeps and which it drops, then show the average and the 0.96 step landing on a single index. The shareable link lets them reopen the exact example at home and change one score to see the index move.

Golf Handicap Calculator — WHS Handicap Index and Score Differential

Score differential and WHS Handicap Index from your rounds, best-N averaged ×0.96, single-round quick mode, one-click copy, browser-only

Runs locally
Category Calculator
Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.

Mode

Round 1Score differential: 13.0

Adjusted gross score

Course Rating

Slope Rating

Round 2Score differential: 14.9

Adjusted gross score

Course Rating

Slope Rating

Round 3Score differential: 11.5

Adjusted gross score

Course Rating

Slope Rating

Handicap Index

11.0

Counting best 1 of 3 rounds · Average of best differentials × 0.96

113 is the standard slope; a course of average difficulty.

What this tool does

A golf handicap calculator built on the World Handicap System. Enter the adjusted gross score, Course Rating and Slope Rating for each round and the tool computes every score differential, then averages the best ones into a Handicap Index. The single-round formula is (score minus Course Rating) times 113 divided by Slope Rating, where 113 is the standard slope of a course of average difficulty. The Index uses the official WHS lookup: with 20 or more rounds on file it averages your best 8 differentials, with fewer rounds it counts proportionally fewer, then multiplies the average by 0.96 and truncates to one decimal. A quick mode gives the differential for a single round when that is all you need. Everything runs in your browser, one click copies the result, and the shareable link reproduces your exact scorecard. 100 percent client-side, nothing uploaded.

Tool details

Input: Numbers; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 10 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Calculator · Content Creator; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How Golf Handicap Calculator fits into your work

Use it for fast estimates, comparisons, and planning numbers before you make the final call.

Calculation jobs

Getting a realistic range before a purchase, plan, workout, or schedule decision.
Comparing scenarios by changing one input at a time.
Turning rough assumptions into a number you can discuss.

Calculation checks

Double-check units, dates, rates, and rounding assumptions.
Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
Save the inputs that produced an important result so you can reproduce it later.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Track your Handicap Index between official updates
Your club posts a revised index on the first of the month, but you have played four cards since then. Enter every recent round with its Course Rating and Slope, and the tool shows where your index is trending right now, using the same best-of lookup the official system uses. You walk to the first tee already knowing roughly what strokes you will get.
Compare two courses before booking a trip
You are choosing between two resort layouts. One is rated 72.0 at slope 118, the other 70.5 at slope 132. Punch a realistic score into quick mode for each and read the differential. The harder course converts the same raw round into a lower differential, so you can see which one actually flatters your handicap before you pay for the tee time.
Sanity-check a differential your app reported
A scoring app spit out a differential that looked off. Type the score, Course Rating and Slope into quick mode and check the math yourself: (score minus rating) times 113 divided by slope. If the numbers disagree you know the app used the wrong rating or slope for the tee you played, which is the usual culprit.
Teach a new golfer how the index is built
Explaining the WHS to a beginner is easier with numbers on screen. Add a handful of rounds, point out which differentials the best-of table keeps and which it drops, then show the average and the 0.96 step landing on a single index. The shareable link lets them reopen the exact example at home and change one score to see the index move.

Common pitfalls

Swapping Course Rating and Slope Rating. Course Rating is a score like 72.0; Slope Rating is an integer from 55 to 155, usually near 113. Putting the slope where the rating goes produces a wildly wrong differential, so check that the decimal value is the rating and the whole number is the slope.
Using the slope or rating from the wrong set of tees. Each tee box has its own Course Rating and Slope. If you played the blues but enter the white-tee numbers, the differential is off for every round. Read the values from the scorecard line matching the tees you actually played.
Expecting an index from one or two rounds. The WHS needs at least 3 acceptable scores before it issues any Handicap Index, and the number stays jumpy until you reach 20 rounds. A single great round does not set your handicap on its own.

Privacy

Every step runs as plain JavaScript inside your browser tab: the score differential, the best-of selection, the average and the 0.96 step. No score, Course Rating or Slope ever leaves the page, and nothing is logged. One caveat: the shareable link encodes your rounds in the query string, so a link pasted into chat records those scores in the recipient server access log. If your scores are private, use the copy button and paste the index instead of sharing the URL.

FAQ

Tool combos

Folks in your role tend to reach for these alongside this tool.

Content Creator

Browse all tools for this role

Golf Handicap Calculator — WHS Handicap Index and Score Differential

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How Golf Handicap Calculator fits into your work

Calculation jobs

Calculation checks

Good next steps

Real-world use cases

Track your Handicap Index between official updates

Compare two courses before booking a trip

Sanity-check a differential your app reported

Teach a new golfer how the index is built

Common pitfalls

Privacy

FAQ

Percentage Calculator

Statistics Basic Calculator

Unit Converter

Aspect Ratio Calculator

24-Point Solver & Game

555 Timer Calculator

A1C to Blood Glucose Calculator

Add Days to Date Calculator

Age Calculator

Age Difference Calculator

AI Token Counter

Airline Luggage Allowance Checker