Quantity limit
A quantity limit is not the billable units on an NDC crosswalk row. Billable units are a Part B pricing concept from the ASP file.
Source: Medicare.gov, Drug plan rules. Page read October 14, 2026.
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Definition · Codes and claim data
Quantity limit
A quantity limit is the maximum amount of a drug a plan will cover in a set period, such as a 30-day supply or a number of tablets. Medicare Part D plans publish these limits on their formularies. This site does not publish formulary pages, so it does not show a limit for a specific plan and drug.
Questions
Quantity limit, answered
Are billable units a quantity limit?
No. Billable units come from the CMS ASP crosswalk for Part B drugs. A quantity limit is a Part D plan rule.