Fixed Price vs Time and Materials vs Retainer

Quick answer

Fixed Price is one set price for defined scope — vendor bears overrun risk; Time and Materials is pay actual effort + materials — buyer bears scope risk — the difference, and when each applies, below.

The 30-second answer

Fixed Price: One set price for defined scope — vendor bears overrun risk. Time and Materials: Pay actual effort + materials — buyer bears scope risk. Retainer: Recurring fee for ongoing availability/work. The difference matters when you’re picking the right tool for the situation.

Side by side

Fixed Price in depth

One set price for defined scope — vendor bears overrun risk — use it clear, stable scope.

Time and Materials in depth

Pay actual effort + materials — buyer bears scope risk — use it evolving scope.

Retainer in depth

Recurring fee for ongoing availability/work — use it ongoing relationships.

Which one when

• Use Fixed Price when clear, stable scope.
• Use Time and Materials when evolving scope.
• Use Retainer when ongoing relationships.

In practice they coexist — the skill is knowing which fits the moment.

Bottom line

Fixed Price is one set price for defined scope — vendor bears overrun risk; Time and Materials is pay actual effort + materials — buyer bears scope risk — the difference, and when each applies, below.

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