Methodology & Version Register

Every calculator on this site implements a published formula from a named governing-body document. This page lists every formula, coefficient set and table version we use, the body that publishes it, and the date we last checked it against the source.

Last updated 23 August 2026

Our commitment

We publish sports scoring and performance calculators that show their working. Every tool states the formula it uses, the governing body and document version it comes from, the assumptions it makes, and what the number does and does not mean.

Why method and version transparency matter

Sports scoring formulas are versioned. Coefficient sets get revised — Wilks was revised; the IPF replaced its old points system with GL; age-grade factor tables are reissued; World Aquatics base times are re-based after major championship cycles. A calculator running a 2015 coefficient set and presenting it as current is wrong in a way a reader can catch.

Every calculator on this site follows four rules:

Cite the governing body, the document, the table year or version, and the date we checked it. Not “IPF formula” but “IPF GL coefficients, IPF Technical Rules, 2020 revision — checked 23 August 2026.”
Offer a version selector where more than one version is in live use. Wilks and Wilks-2 both circulate. We label which is default and why.
Link to the official publication rather than republishing large tables wholesale. Implementing a published formula is appropriate — formulas are not copyrightable expression. Republishing a full copyrighted table is reproducing someone else’s compilation. We publish the handful of rows a worked example needs, describe the table’s structure, and link to the source for the rest.
Never invent a coefficient, a base time, or a factor. If we cannot find the published value, the tool does not ship that event.

Formulas by calculator

1. Score Differential (Golf)

A single round’s differential under the World Handicap System, per the WHS Rules of Handicapping (USGA / R&A), 2024 edition — checked 23 August 2026.

Score Differential = (113 / Slope Rating) × (Adjusted Gross Score − Course Rating − PCC) Round the differential to one decimal place.

AGS: Adjusted Gross Score, after the net double bogey adjustment
CR: Course Rating for the tee played (strokes, one decimal)
Slope: Slope Rating for the tee played (55–155; 113 = standard difficulty)
PCC: Playing Conditions Calculation, an adjustment of −1 to +3. Set to 0 unless the reader has been given a value.

Accuracy note

Only an authorised golf association or affiliated club can issue an official Handicap Index. This tool produces an estimate from the numbers you enter. It cannot see your scoring record, cannot apply soft or hard caps, cannot apply an exceptional-score reduction, and does not know your local association’s variations.

2. Handicap Index (Golf)

Handicap Index from a scoring record, per the WHS Rules of Handicapping (USGA / R&A), 2024 edition — checked 23 August 2026.

Handicap Index = average of the LOWEST 8 Score Differentials among the MOST RECENT 20 acceptable scores (rounded to one decimal) With fewer than 20 scores, WHS applies a published reduced-count table (e.g. 3 scores → lowest 1 minus an adjustment).

The reduced-count table is implemented from the Rules of Handicapping and cited by section number.

3. Course Handicap & Playing Handicap (Golf)

Per the WHS Rules of Handicapping (USGA / R&A), 2024 edition — checked 23 August 2026.

Course Handicap = Handicap Index × (Slope Rating / 113) + (Course Rating − Par) rounded to the nearest whole number Playing Handicap = Course Handicap × Handicap Allowance

Handicap Allowance: Varies by format (e.g. singles stroke play, four-ball, stableford). Taken as user input with published defaults preloaded.

Note: the (CR − Par) term is part of the current Course Handicap formula and was not present in earlier versions.

4. Running Pace, Speed & Finish Time

Standard distance and pace arithmetic. Distances per World Athletics Competition and Technical Rules — checked 23 August 2026.

Pace (min/km) = time_seconds / distance_km / 60 Pace (min/mile) = time_seconds / distance_miles / 60 Speed (km/h) = distance_km / (time_seconds / 3600) Finish time = pace_seconds_per_unit × distance_units 1 mile = 1.609344 km exactly

Standard distances: 5K, 5 mile, 10K, 10 mile, half marathon (21.0975 km), marathon (42.195 km).

5. Race Time Prediction (Riegel)

Riegel’s endurance formula, the most-cited predictor in distance running. Source: Riegel, P.S. (1981), “Athletic Records and Human Endurance,” American Scientist, 69(3), 285–290. Checked 23 August 2026.

T2 = T1 × (D2 / D1) ^ 1.06

T1, D1: A known race time and its distance
T2, D2: The predicted time at the target distance
1.06: Riegel’s fatigue exponent (adjustable input, 1.05–1.08)

Accuracy note

Riegel was derived from race results. It over-predicts for athletes stepping up in distance without the training volume to match, and is least reliable outside roughly 3 minutes to 4 hours. A VDOT-style equivalence (Daniels and Gilbert) is offered as a second opinion — it is an oxygen-cost model fitted to elite and trained-runner data.

6. Age Grading

Factors from the World Masters Athletics age-grade factor tables — table year and date checked are displayed on the calculator page.

Age-graded time = actual time × age factor Age-grade % = (open standard for the event / age-graded time) × 100 Age standard = open standard / age factor

Accuracy note

Age grading compares a performance to the best expected for that age and sex at that event. It is a comparison, not a prediction. Different sites use different table years and will therefore disagree by a few tenths of a percent. The table year is visible in the calculator output.

7. Wilks Score

Source: published Wilks coefficient set. Both the original and revised (“Wilks-2”) coefficient sets are offered via a version selector. Checked 23 August 2026.

coefficient = 500 / (a + b·x + c·x² + d·x³ + e·x⁴ + f·x⁵) Wilks score = total_lifted_kg × coefficient x = body weight in kg a–f are sex-specific published constants

Accuracy note

Wilks was superseded inside the IPF by GL points. A score is only comparable against scores computed with the same coefficient set. These are population-fitted comparison scores, not measures of ability. They are sensitive to body weight near the extremes of the fitted range, differ between equipment classes, and say nothing about whether a lift was judged legal.

8. IPF GL Points (with DOTS)

Source: IPF Technical Rules, 2020 revision and the IPF’s published GL points documentation — checked 23 August 2026.

GL points = total_kg × 100 / (A − B · e^(−C · bodyweight_kg)) A, B, C are published per sex, per lift type (full power vs bench only) and per equipment class (classic vs equipped) DOTS coefficient = 500 / (a + b·x + c·x² + d·x³ + e·x⁴) DOTS score = total_kg × DOTS coefficient

9. Swimming Points

Source: World Aquatics (formerly FINA) points tables — identified by the table year in force. Checked 23 August 2026.

Points = 1000 × (base time / swim time)³ base time: the published base time for that event, course (LCM/SCM/SCY), sex and age category Pace per 100 = swim time / (distance_m / 100) Result is truncated to a whole number of points.

Accuracy note

1000 points is the reference standard for the table year, not a world record. Scores across course types (LCM, SCM, SCY) are not directly comparable. The cube relationship means small time differences move points sharply at the fast end. The table year is visible in the calculator output.

10. Cricket Run Rates & Net Run Rate

Source: ICC Standard Playing Conditions, per format (Men’s/Women’s ODI and T20I are separate documents) and edition — checked 23 August 2026.

Overs to decimal: overs_decimal = completed_overs + (balls / 6) 45.3 overs (45 overs, 3 balls) → 45.5 in decimal Run rate RR = runs / overs_decimal Required run rate RRR = (target − current runs) / overs_remaining_decimal where target = opposition score + 1 Net run rate NRR = (total runs scored / total overs faced) − (total runs conceded / total overs bowled)

Accuracy note

A team bowled out counts the full allotted overs, not the overs actually faced, in the NRR calculation. Abandoned or no-result matches are excluded per the relevant competition rules. Getting these two rules right is the reason to use a calculator over a rough division.

Authority and source hierarchy

We cite primary sources in this order of precedence. Secondary summaries and other websites are never a source.

Body	Documents cited by name	Version / Edition	Date checked
USGA and R&A	Rules of Handicapping (World Handicap System), by rule number and edition; Course Rating System description	2024 edition	23 Aug 2026
International Powerlifting Federation	IPF Technical Rules; published GL points documentation and coefficient tables	2020 revision	23 Aug 2026
World Athletics	Competition and Technical Rules (course distances, timing, records); official distance definitions	2025–2026 edition	23 Aug 2026
World Masters Athletics	Age-grade factor tables and accompanying explanatory notes	Identified by table year on each calculator	23 Aug 2026
World Aquatics (formerly FINA)	Points tables by year in force; Swimming Rules for course definitions (LCM/SCM/SCY)	Identified by table year on each calculator	23 Aug 2026
International Cricket Council	Standard Playing Conditions per format and edition (run rate, NRR, bowled-out treatment); ICC’s published description of DLS — for reference only	Current edition per format	23 Aug 2026
Peer-reviewed literature	Riegel (endurance exponent); Daniels and Gilbert (VO₂/VDOT equivalence). Linked via DOI or PubMed.	Original publication years	23 Aug 2026

Version register

This table lists every coefficient set, factor table and base-time set the site uses. It is updated when a governing body revises its standards or when we add a new calculator.

Data set	Publishing body	Version / Year	Date checked	Tools affected
WHS Rules of Handicapping	USGA / R&A	2024 edition	23 Aug 2026	Golf Handicap Index, Course Handicap, Score Differential
WHS reduced-count table	USGA / R&A	2024 edition	23 Aug 2026	Golf Handicap Index
WHS handicap allowance table	USGA / R&A	2024 edition	23 Aug 2026	Course Handicap (Playing Handicap)
Wilks coefficients (original)	Published coefficient set	Original	23 Aug 2026	Wilks calculator
Wilks-2 coefficients (revised)	Published coefficient set	Revised	23 Aug 2026	Wilks calculator
IPF GL coefficients	International Powerlifting Federation	2020 revision	23 Aug 2026	IPF GL Points calculator
DOTS coefficients	Published coefficient set	Current	23 Aug 2026	IPF GL Points calculator (alt output)
WMA age-grade factor tables	World Masters Athletics	Table year displayed on calculator	23 Aug 2026	Age Grading calculator
World Aquatics base times	World Aquatics (formerly FINA)	Table year displayed on calculator	23 Aug 2026	Swimming Points calculator
Riegel fatigue exponent	Peer-reviewed: Riegel (1981)	Original (1.06)	23 Aug 2026	Race Time Predictor
ICC NRR and run-rate definitions	International Cricket Council	Current playing conditions per format	23 Aug 2026	Net Run Rate calculator
World Athletics standard distances	World Athletics	2025–2026 edition	23 Aug 2026	Running Pace, Race Time Predictor, Age Grading

What we do not calculate

This site computes from published rules. It does not predict outcomes and does not advise on health.

Hard exclusions

The following are explicitly excluded from this site and will not be built:

Betting odds, implied-probability tools, expected-value or staking calculators, Kelly criterion, arbitrage, parlay or accumulator math, tipping or “value bet” tools.
Match, tournament or season outcome predictors, including “chance of qualification” tools.
Anything requiring a live data feed: live scores, live tables, in-play run rates, real-time leaderboards.
Anything requiring licensed athlete data: player databases, career stat lookups, ranking-point tables scraped from a governing body.
DLS (Duckworth–Lewis–Stern): the resource tables and algorithm are proprietary. We explain what DLS does and why rain targets are not a run-rate calculation. We never compute a DLS par score.
Any reimplementation of a proprietary algorithm, including World Golf Ranking points, ATP/WTA ranking computations, and any commercial performance index.
Diagnoses, injury interpretation, medical or return-to-play guidance.
Training prescriptions, nutrition plans, weight targets, or individual programmes.

For physiological tools (heart-rate zones, training load) that are health-adjacent, we apply the full treatment: reference framing, a named linked citation to the primary paper, a consult-a-professional note, and a link to the editorial policy and its negative-claims block.