Latest reports from L'Equipe, relayed by Get French Football, reveal the length of the contract the France international is set to sign at Stamford Bridge today which will tie him to the club until 2020.
Giroud's move across London was triggered after Arsenal agreed terms with Borussia Dortmund over the transfer of Pierre-Emerick Aubameyang yesterday, with the Gabon international jetting into the capital on Monday to complete his £55.4m transfer.
According to L'Equipe, the bid Arsenal have accepted for their striker is actually worth less than an initial bid submitted by Chelsea early on Monday morning. The report suggest that opening offer was worth £20m excluding bonuses, one the Gunners failed to respond to in time as they were focusing on tying up a deal for Aubameyang.
The French publication say today's deal will go through for €20m (£17.5m) including bonuses in a deal overseen by Chelsea's chief negotiator Marina Granovskaia.
Giroud played his last game for the Gunners on Monday night as his side crashed to a 3-1 defeat to the Premier League's bottom club Swansea City. After coming on as a late sub with 15 minutes of the match remaining, the 31-year-old was powerless to prevent defeat, waving goodbye to Arsenal's travelling support as he left the pitch at full-time.
Despite wide-ranging reports of a deal, Wenger remained coy on the Frenchman's departure.
"It's a possibility [that Giroud will join Chelsea], but all that will be decided tomorrow morning. We will inform you once that is more definite."
He added in his post-match press conference: "At the moment I don't want to talk too much about where he goes, if he goes. That will be definitely decided [tomorrow], nothing is concluded at the moment."
Giroud will become Chelsea's third arrival of the January window following the signings of Ross Barkley and Emerson Palmieri.