A fixed-ratio schedule delivers reinforcement after a set number of responses. The ratio remains constant: every fifth response, or every twentieth, produces the reinforcer.

The schedule generates a high, steady rate of responding, often with a brief pause after each reinforcer. Piecework payment—pay for every dozen items completed—is a classic real-world example. The organism learns that a specific amount of work is required and tends to complete that work rapidly. Higher ratios produce longer post-reinforcement pauses and can eventually strain the behavior if the requirement becomes too high.

Fixed-ratio schedules are relatively resistant to extinction compared with continuous reinforcement, yet less so than variable-ratio schedules. They are widely used in training because the contingency is clear and the rate of reinforcement is directly under the learner’s control: faster responding produces faster payoffs.

When the rule is “do it this many times and you get the reward,” the fixed-ratio schedule is in force.