13.—(1) The amount of an award of universal credit is to be the balance of—
(a)the maximum amount (see paragraph (2)), less
(b)the amounts to be deducted (see paragraph (3)).
(2) The maximum amount is the total of—
(a)any amount included under Article 14 (standard allowance),
(b)any amount included under Article 15 (responsibility for children and young persons),
(c)any amount included under Article 16 (housing costs), and
(d)any amount included under Article 17 (other particular needs or circumstances).
(3) The amounts to be deducted are—
(a)an amount in respect of earned income calculated in the prescribed manner (which may include multiplying some or all earned income by a prescribed percentage), and
(b)an amount in respect of unearned income calculated in the prescribed manner (which may include multiplying some or all unearned income by a prescribed percentage).
(4) In paragraph (3)(a) and (b) the references to income are—
(a)in the case of a single claimant, to income of the claimant, and
(b)in the case of joint claimants, to combined income of the claimants.