BBC Sport's fuel-adjusted Turkish GP grid
Sebastian Vettel may have claimed his second pole of the season but the figures confirm that is because his Red Bull had less fuel in the tank.
The cars in the top-10 shoot-out are not allowed to refuel between qualifying and race, so they go into qualifying with differing fuel loads depending on how long their first stint in the race is going to be.
The fuel-adjusted grid, with estimated first pit-stop laps, looks like this:
1. Jenson Button - lap 17
2. Sebastian Vettel - lap 15
3. Mark Webber - lap 17
4. Rubens Barrichello - lap 16
5. Kimi Raikkonen - lap 17
6. Jarno Trulli - lap 16
7. Felipe Massa - lap 16
8. Nico Rosberg - lap 18
9. Robert Kubica - lap 20
10. Fernando Alonso - lap 14
Vettel drops to second place as he is six kilos lighter than the championship leader.
He will be forced to stop two laps earlier than the Englishman and is less than a tenth of a second slower.
Australian Mark Webber is just behind his Red Bull team-mate in third place which will boost the team's hopes of getting both cars on the podium.
What the figures also show is that Rubens Barrichello is one lap lighter on fuel than his team-mate Button but still qualified behind him.
The Brazilian's genuine pace dropped him back to fourth on the grid. Given he had less fuel on board, he may now be considering whether qualifying on hard tyres was the right decision.
Kimi Raikkonen out-qualified three-time Turkish GP winner Felipe Massa.
And he is also four kilos heavier than his Ferrari team-mate, putting him fifth on the grid and leaving Massa seventh based on fuel loads.
Toyota's Jarno Trulli drops from fifth to sixth in the fuel-adjusted times whilst Williams' Nico Rosberg climbs from ninth to eighth with 4.5 kilos more fuel on board than Button.
BMW Sauber's Robert Kubica also moves up one place from 10th to ninth and is the heaviest of the top-10 qualifiers and won't need to stop for fuel for 20 laps, suggesting BMW's performance relative to Button is improving.
As ever, the lightest car in the top 10 is double world champion Fernando Alonso's Renault.
He will have to stop for fuel by lap 13 and the Renault's real pace is over a second a lap slower than Button making the Spaniard the last of the top 10 qualifiers on fuel-adjusted times.
Just one more thing, the top seven are covered by less than half a second which could make for a dramatic race in Istanbul.