Golf Handicap Calculator

What is a golf handicap calculator?

A golf handicap calculator turns one round of golf into a single, comparable number called a handicap differential. You enter three values from your scorecard — your adjusted gross score, the course rating, and the slope rating of the tees you played — and the tool returns the differential for that round under the World Handicap System (WHS). The differential is the building block of your handicap: your official Handicap Index is the average of your best 8 differentials from your most recent 20 rounds, and this calculator gives you the differential for one of those rounds.

Enter your numbers in the box above and press Calculate. The math runs entirely in your browser, so your scores are never uploaded or stored.

How does the golf handicap formula work?

The calculator applies the standard WHS score differential formula:

differential = (adjusted gross score − course rating) × 113 ÷ slope rating

Every symbol, with its unit:

• Adjusted gross score — your total strokes for the round after applying the per-hole maximum (net double bogey). A whole number of strokes, for example 90.
• Course rating — the score a scratch (zero-handicap) golfer is expected to shoot on those tees, in strokes, printed to one decimal such as 70.0. It reflects the course’s difficulty for an expert.
• Slope rating — a number describing how much harder the course plays for a bogey golfer than for a scratch golfer. Real slopes run from 55 to 155; this tool requires a positive slope (a zero or negative slope is invalid and division by it is undefined).
• 113 — the slope rating of a course of standard playing difficulty. It is a fixed constant, not something you change.

The logic is: subtract the course rating from your score to see how many strokes over (or under) scratch level you played, then multiply by 113 and divide by your slope to rescale that result onto the neutral baseline. Because every course is mapped back to 113, a differential of 18.1 means the same thing whether you earned it on an easy course or a brutal one. The result is shown to one decimal place.

This tool computes one round’s differential. To get an official Handicap Index, you average the lowest 8 of your last 20 differentials — a step you do across many rounds, not in a single calculation.

Examples

Each example uses the formula above exactly, so you can reproduce every number by typing the same three inputs into the calculator.

Example 1 — score 90 on a 70.0 / 125 course

Adjusted gross score 90, course rating 70.0, slope 125:

(90 − 70.0) × 113 ÷ 125 = 20 × 113 ÷ 125 = 2260 ÷ 125 = 18.1

You played 20 strokes over the scratch rating, and after rescaling to the neutral 113 slope that round is worth a differential of 18.1.

Example 2 — score 85 on a 71.2 / 130 course

Adjusted gross score 85, course rating 71.2, slope 130:

(85 − 71.2) × 113 ÷ 130 = 13.8 × 113 ÷ 130 = 1559.4 ÷ 130 = 12.0

A tidy 85 on a slightly harder, higher-rated course produces a differential of 12.0 — lower than Example 1 because the gap to the rating was smaller.

Example 3 — score 100 on a 72.0 / 140 course

Adjusted gross score 100, course rating 72.0, slope 140:

(100 − 72.0) × 113 ÷ 140 = 28 × 113 ÷ 140 = 3164 ÷ 140 = 22.6

A high score on a very tough course (slope 140) still gives a differential of 22.6 rather than the full 28-over, because the steep slope discounts each stroke you played above rating.

Example 4 — score 95 on a 71.5 / 132 course

Adjusted gross score 95, course rating 71.5, slope 132:

(95 − 71.5) × 113 ÷ 132 = 23.5 × 113 ÷ 132 = 2655.5 ÷ 132 = 20.1

This round lands at a differential of 20.1.

Example 5 — score 80 on an easier 69.5 / 118 course

Adjusted gross score 80, course rating 69.5, slope 118:

(80 − 69.5) × 113 ÷ 118 = 10.5 × 113 ÷ 118 = 1186.5 ÷ 118 = 10.1

An 80 on a gentler course (slope 118) returns a differential of 10.1 — proof that a lower raw score does not automatically mean a lower differential, because the course’s rating and slope both matter.

Course rating and slope reference

The table works the formula for the same adjusted gross score (90) across courses of different difficulty, so you can see how rating and slope move the differential. The harder the course, the lower the differential a given score earns.

Score	Course rating	Slope	Calculation	Differential
90	68.0	113	(90 − 68.0) × 113 ÷ 113	22.0
90	70.0	113	(90 − 70.0) × 113 ÷ 113	20.0
90	70.0	125	(90 − 70.0) × 113 ÷ 125	18.1
90	71.2	130	(90 − 71.2) × 113 ÷ 130	16.3
90	72.0	140	(90 − 72.0) × 113 ÷ 140	14.5
90	73.0	150	(90 − 73.0) × 113 ÷ 150	12.8

When the slope equals the standard 113, the × 113 ÷ 113 cancels and the differential is simply your score minus the course rating.

Common uses

A golf handicap calculator is useful whenever you want a fair, portable measure of a round:

• Posting a score by hand when you are away from your federation’s app and want to know that round’s differential before you log it.
• Tracking your trend by computing a differential after each round and watching whether your recent numbers are dropping.
• Comparing two rounds on different courses — the differential rescales both to the 113 baseline, so a 92 on a hard track can beat an 88 on an easy one.
• Estimating your index by collecting differentials and averaging your best 8 of the last 20.
• Setting up a fair match between players of different abilities, since handicaps let a beginner and a low-marker compete on level terms.

Tips and common mistakes

• Use adjusted gross, not raw, score. The World Handicap System caps each hole at net double bogey, so a blow-up hole does not wreck your differential. Apply that maximum before entering your score.
• Read the right tees. Course rating and slope change with the tee box you play. Take both numbers from the row on the scorecard for the tees you actually used.
• Do not confuse rating and slope. Course rating is a strokes figure near par (often 67–75); slope is a 55–155 number near 113. Swapping them gives a nonsense result.
• A differential is one round, not your handicap. This single number is an input to your index, which is the average of your best 8 of 20 differentials — it is normal for one round to sit above or below your index.
• Course Handicap is a separate step. To convert an index into strokes received at a specific tee, use Course Handicap = Handicap Index × slope ÷ 113. That is downstream of this calculator’s differential.
• Slope must be positive. A slope of 0 (or a blank) cannot be used because the formula divides by it; enter the real slope from the card, which is always at least 55.

Limitations and notes

This tool computes a single round’s score differential using the standard WHS formula and the neutral slope constant of 113. It does not assemble your full record: it will not pull your last 20 scores, drop the worst 12, or average the best 8 into a finished Handicap Index — those steps happen across many rounds and are handled by your golf association. It also does not apply the playing-conditions calculation (PCC) or the soft/hard caps that the official system layers on top, and it assumes you have already worked out your adjusted gross score under net double bogey. Treat the differential as the accurate per-round number it is, then average the best 8 of your last 20 to approximate your index. Everything runs privately in your browser, so you can calculate as many rounds as you like without your scores leaving your device.

For more scorekeeping and rating math, try the bowling score calculator or the chess rating calculator, use the percentage calculator to track your trend, and browse the full sports category.