The calculation for trades tool allowance also includes the Canada employment amount, so the cost of the tools has to be greater than $1,146.

Per CRA:

Maximum deduction for eligible tools is the lesser of:

a) $500; and

b) the amount, if any, determined by the formula

A − $1,146 where

A = the lesser of:

1. the total cost of eligible tools that you bought in 2015; and

2. your income from employment as a tradesperson for the year

plus the amount you received in 2015 under the Apprenticeship Incentive Grant and the Apprenticeship Completion Grant programs;

minus the amount of any Apprenticeship Incentive Grant and Apprenticeship Completion Grant overpayments that you had to repay in 2015.