Full Budget deals with both expenditure and revenue side but Vote-on-account deals only with the expenditure side of the government’s budget.
The vote-on-account is normally valid for two months but a full budget is valid for 12 months (a financial year).
As a convention, a vote-on-account is treated as a formal matter and passed by Lok Sabha without discussion. But passing for budget happens only after discussions and voting on demand for grants.
A vote-on-account cannot alter direct taxes since they need to be passed through a finance bill. Under the regular Budget, fresh taxes may be imposed and old ones may go.
An interim budget in all practical sense is a full budget but made by the government during the last year of its term – i.e. just before the election. An interim Budget is a complete set of accounts, including both expenditure and receipts. But it may not contain big policy proposals.
It is not mandatory for the government to present a vote on account in an election year.