NDC 10 to 11 digit converter
Type the NDC exactly as it's printed on the label, hyphens included, and get the 11-digit 5-4-2 version used on insurance claims.
For studying and practice only. This isn't a clinical tool: always follow the prescriber's order, your pharmacist, and your facility's policies.
How NDC conversion works
The National Drug Code on a package is 10 digits split into three segments: labeler, product and package. Manufacturers use one of three layouts (4-4-2, 5-3-2 or 5-4-1). Billing systems need a single 11-digit 5-4-2 layout, so one segment gets a leading zero.
| Label format | Add a zero to | Label NDC | 11-digit NDC |
|---|---|---|---|
| 4-4-2 | Labeler (first) | 1234-5678-90 | 01234-5678-90 |
| 5-3-2 | Product (middle) | 12345-678-90 | 12345-0678-90 |
| 5-4-1 | Package (last) | 12345-6789-0 | 12345-6789-00 |
Worked example
Label NDC 54321-123-45 (5-3-2)
- middle segment has 3 digits → pad to 4: 123 → 0123
- 11-digit NDC = 54321-0123-45 (54321012345)
Practice these calculations the way the PTCB exam asks them
Try free PTCE practice questions on order entry and processing, including weight-based dosing and NDC conversion, with explanations. No signup.
Practice calculation questions freeFrequently asked questions
- How do you convert a 10-digit NDC to 11 digits?
- Find the segment that's one digit short of the 5-4-2 layout and add a leading zero to it: the first segment for 4-4-2, the middle for 5-3-2, and the last for 5-4-1.
- Why do I need the hyphens?
- Without them a 10-digit NDC is ambiguous: the same ten digits split differently in 4-4-2, 5-3-2 and 5-4-1, so the zero could belong in three different places. Always copy the hyphens from the label.
- What do the three parts of an NDC mean?
- The first segment identifies the labeler (the manufacturer, repackager or distributor), the second the product (drug, strength and dosage form), and the third the package size and type.
- Can I just add a zero to the front?
- Only for a 4-4-2 NDC. For 5-3-2 the zero goes at the start of the middle segment, and for 5-4-1 at the start of the last segment. Putting it in the wrong place creates a different, wrong NDC.