He was born in Steeple, Dorset, of a branch of an old Dorsetshire family, being baptised there on 18 September 1632.
Clavell was the author of a curious little treatise entitled His Majesties Propriety and Dominion on the British Seas asserted: together with a true Account of the Neatherlanders' Insupportable Insolencies, and Injuries they have committed; and the Inestimable Benefits they have gained in their Fishing on the English Seas: as also their Prodigious and Horrid Cruelties in the East and West Indies, and other Places.
John Dunton describes Clavell as "a great dealer, who has deservedly gained himself the reputation of a just man.
His will, as "citizen and stationer of London", dated 17 April 1711, was proved on the following 8 August by Catherine Clavell, his widow (registered in P.C.C.
Mrs. Clavell survived her husband until the close of 1717, dying in the parish of St. Margaret, Westminster (will registered in P.C.C.