What are the main types of construction contracts?

Contract types: Lump Sum (Fixed Price) - contractor agrees to complete work for specified amount, transfers risk to contractor. Unit Price - payment based on quantities of work items at agreed rates, used when quantities uncertain. Cost Plus - owner reimburses costs plus fee (percentage or fixed), owner bears risk. Guaranteed Maximum Price (GMP) - cost plus with ceiling, savings may be shared. Time and Materials - labor rates plus material costs, for undefined scope. Selection balances risk allocation, scope definition, and project needs.