https://overthecap.com/salary-cap/miami-dolphins/
Has them at 52m IN Space (ALL Contracts accounted for)
https://www.spotrac.com/nfl/miami-dolphins/cap/
65M in space (No Grugier-Hill, Howard, Lawson or Ogbah contracts accounted for)
They also need 18M in for their Rookie Pool. So that leaves them with 38M roughly in space by OTC numbers