How does a copay differ from a deductible in health insurance? How does a copay differ from a deductible in health insurance? Copay is paid at each visit, while the deductible is an annual amount before insurance coverage starts. Copay is a percentage of the medical bill, while the deductible is a fixed amount. Copay is paid by the insurer, while the deductible is paid by the patient. Copay and deductible are terms used interchangeably in health insurance