Top 10 Mastiff and Bull Dog Breeds with the Strongest Bite Force

Mastiffs have the strongest bite - the first 6 species on this list are Mastiffs. From 7 to 10 are Bull Dogs - another breed with a very strong bite.
PSI is “Pound per Square Inch” / “Pound-force per Square Inch”. PSI measures the bite force.

The Top Ten

1 Kangal - 743 psi

So strong they should be higher on dog lists

It's a Turkish dog. - Metal_Treasure

2 Cane Corso - 700 psi
3 Dogue de Bordeaux - 556 psi
4 English Mastiff - 552 psi The English Mastiff is a breed of extremely large dog perhaps descended from the ancient Alaunt and Pugnaces Britanniae, with a significant input from the Alpine Mastiff in the 19th century.
5 Dogo Canario - 540 psi
6 Dogo Argentino - 500 psi The Dogo Argentino, also known as the Argentine Mastiff, is a large, white, muscular dog that was developed in Argentina primarily for the purpose of big-game hunting, including wild boar; the breeder, Antonio Nores Martínez, also wanted a dog that would exhibit steadfast bravery and willingly protect more.

Really strong for their size

7 American Bulldog - 305 psi The American Bulldog is a breed of utility dog. There are two specific types of American Bulldog, Standard and Classic; additionally, there are also hybrids of the two types.
8 Pit Bull - 235 psi The American Pit Bull Terrier is a dog breed. It is a medium-sized, solidly-built, short-haired dog whose early ancestors came from the British Isles.
9 Alano Español - 227 psi
10 English Bulldog - 210 psi