A build-up is one method of calculating an expatriate salary. Essentially,  the assignee's notional home salary is broken down and then built up again taking account of changes in living costs, any additional allowances, differences in tax regimes and any benefits supplied to the assignee.

ECA's Client Services department can calculate build-ups for member companies. Non-members can get a calculation as part of a International Assignment Report through ECA's Consultancy department.

Build-ups can also be calculated using ECA Calc, a software application available to ECA Members.