What Double Start Actually Costs a World Grand Prix Average

No fixed World Grand Prix double-in average drop has been established. The one quantified figure in the reviewed sources is a secondary report of Christopher Kempf’s analysis of the 2023 final: Luke Humphries’ official average was 93.30, and Kempf reportedly recalculated the same performance at 99.70 without the double-start requirement, a difference of 6.40 points (DartsNews). Gerwyn Price’s recalculated figure rose by more than six points as well. That is one final, two players and no published visit-level method, so 6.40 is a reported case study, not a correction to add to every Grand Prix average.

What can be stated exactly is the arithmetic. Every zero-scoring opening dart that is counted adds one to the denominator of the average and nothing to the numerator. The calculator below does that sum in either direction for any sample you give it.

Enter a three-dart average, the darts behind it and the zero-scoring opening darts; the converted average updates beside the controls.

No Tournament-Wide Drop Has Been Measured

None of the reviewed sources gives a mean, median or standard reduction caused by double start across a tournament. The quantified comparison covers one final.

DartsNews attributes the analysis to darts statistician Christopher Kempf, identified as @ochepedia. For Humphries the reported sum is 99.70 minus 93.30, which is 6.40 average points. The source does not reproduce Kempf’s underlying data or say which darts were removed or reclassified.

Humphries did not throw 99.70 in a separate straight-in match. The figure is a hypothetical recalculation of his darts in the 2023 World Grand Prix final. The defensible reading is narrow: one reported analysis produced a 6.40-point difference for one performance.

Why Missed Opening Darts Pull the Average Down

In conventional 501, scoring begins with the first dart and the player must reach exactly zero on a double or bullseye. At the World Grand Prix, a player must hit a double or bullseye before scoring can begin and must finish the same way. The successful opening double contributes its value to the 501 total; a failed opening attempt scores zero.

A three-dart average is total points scored divided by darts thrown, multiplied by three.

The mechanism follows directly. If failed opening attempts are counted among the darts thrown, they raise the denominator without raising the points total, and the published average comes out lower than it would if those darts were excluded.

Take a player who misses double 16 with the first dart, hits it with the second and follows with treble 20. The first dart scores nothing; the next two score 32 and 60. Counted as three darts, that visit contributes 92 points from three darts rather than 92 from two.

Missed checkout darts reduce a match average through the same arithmetic. General average guides state that every released dart, including missed checkout attempts, counts in the denominator. A separate general methodology source says a bust on the first or second dart is recorded as a complete three-dart visit, but the reviewed sources do not confirm that convention through an official PDC methodology.

That gap matters. The sources explain the double-start rule, zero-scoring opening misses and the general formula, but none includes an official PDC or statistics-provider passage stating how every failed opening attempt, bust, incomplete visit and losing leg is treated in published World Grand Prix averages. Any explanation of an official figure stays conditional on that.

The 2023 Final: 93.30 Official, 99.70 Recalculated

Figures reported by DartsNews and attributed to Christopher Kempf.

The same report says Price’s adjusted average rose by more than six points. It does not give enough method to reproduce either calculation.

Even accepting the recalculation as reported, one final cannot establish the normal effect across a tournament. The size of the difference depends on opening efficiency, match length, legs played, checkout performance and how particular darts are treated in the calculation.

The correct label for 99.70 is a hypothetical straight-in average for the same performance, not an average Humphries recorded anywhere.

Worked Example: One Zero-Scoring Dart Costs 6.26 Points on a 15-Dart Leg

This is a simplified arithmetic illustration, not World Grand Prix match data and not a reconstruction of Kempf’s method.

A player who scores all 501 points in 15 darts averages 501 divided by 15 times three, which is 100.20. Hold the 501 points constant and add one counted, zero-scoring opening dart: 501 divided by 16 times three is 93.94.

The movement is large because the sample is one completed leg with a small denominator. Over a match, opening attempts are spread across many legs, a losing player does not score all 501 in every leg, and post-entry scoring, checkout misses and darts thrown all vary. Three extra opening darts in a short match do not cost what three extra darts cost in a long one.

So no fixed adjustment follows from the formula. The effect is set by the number of additional zero-scoring darts relative to the size of the whole sample, which is exactly what the calculator above computes.

Why Grand Prix and Straight-In Averages Do Not Convert Cleanly

Opening-double efficiency is only one input to a World Grand Prix match average. Scoring after entry, misses at finishing doubles, bust visits, the number of legs played and set-play variation all move the figure too.

The opening round is scheduled as best of three sets, so a handful of difficult opening visits can be a meaningful share of a short match (2026 format guide). Longer matches give a larger sample, though scoring and finishing still swing from leg to leg.

Subtracting a player’s World Grand Prix match average from an unrelated season average does not isolate the cost of double start. The two samples differ in opponents, match lengths, form, checkout efficiency and post-entry scoring. Nor can a double-in percentage be subtracted from a three-dart average: one measures target conversion, the other points per three darts.

The historical scarcity of 100-plus averages at the event is context, not a measured penalty, and double start sets no ceiling. A community-edited historical table lists Gian van Veen at 106.47 and Luke Littler at 105.58 in their 2025 match, with Van Veen posting the higher figure in defeat. Those figures are source-bounded rather than definitive, because the reviewed evidence does not include an official match report.

A World Grand Prix average combines entry, post-entry scoring and finishing. It is not a pure measure of conventional scoring power.

Reading the 2026 World Grand Prix Numbers

The 2026 World Grand Prix is scheduled for September 28 to October 4 at Mattioli Arena in Leicester, in set play with the double-start format, and the opening round is listed as best of three sets in the published schedule and format guide. These were prospective details when published and may change.

A separate report lists a 32-player field: the top 16 from the main rankings and 16 qualifiers from the one-year ProTour standings (reported 2026 field). Withdrawals or replacements could alter the line-up, so check the latest event listing.

Read each match through four figures together. The overall three-dart average is the headline output. Double-in percentage shows how efficiently the player started scoring. Checkout percentage shows how efficiently legs were closed. Match length is the sample size behind the other three.

A modest overall average can sit beside strong post-entry scoring when a player keeps missing the opening double. A player can also enter legs efficiently and lose ground through checkout misses or weaker scoring after entry.

Compare World Grand Prix performances with other double-start matches first. Compare them with straight-in averages only when the methodology is explicit and the samples are large and closely matched.

A stronger estimate of the double-in effect would need visit-level data separating opening attempts, post-entry scoring and finishing, ideally comparing the same players across matched samples rather than one final against unrelated season averages. Until that exists, the bounded answer stands: a secondary report attributes a 6.40-point difference to Kempf’s recalculation of Humphries’ 2023 final, and nothing in the reviewed evidence turns that into a typical World Grand Prix double-in average drop.