Suppliers hear “CAPA” from auditors and “8D” from customer quality engineers, often about the same problem. The two overlap, but they are not the same thing. This page explains how they relate, what each one is usually expected to show, and how to write one response that works for both. It applies to automotive, aerospace, medical devices, electronics, food, and general manufacturing. Your customer’s format and rules come first.
What CAPA means
CAPA stands for corrective and preventive action. It is a process inside your quality management system: how you record problems, decide which need action, find causes, act, and check the action worked. Quality standards in many sectors expect some form of it. ISO 9001:2015 handles corrective action in clause 10.2 and replaces the separate preventive-action clause with risk-based thinking; medical-device standards such as ISO 13485 still require both corrective and preventive action. A CAPA record can be short or long, and its layout is yours to choose unless a customer or regulator says otherwise.
What 8D means
8D, or eight disciplines, is a problem-solving method and report format: D1 team, D2 problem description, D3 containment, D4 root cause, D5 chosen corrective action, D6 implementation and verification, D7 prevention, D8 closure. Customers ask for it because every supplier’s answer then has the same structure, which makes it quick to check.
How they relate
- CAPA is the process; 8D is one way to run and document a single case inside it.
- A customer 8D usually becomes one CAPA record in your system, or links to one.
- 8D separates containment (D3) from permanent action (D5–D6). Many CAPA forms combine them, so keep them apart when you copy across.
- 8D asks for a cause of occurrence and a cause of escape in D4. Many CAPA forms only ask for one root cause.
- 8D D7 prevents recurrence through system changes, which is still corrective action. Extending the fix to similar products and processes that have not failed yet is the part that matches preventive action in a CAPA system.
For the containment split, see 8D corrective action vs containment . For the escape side of D4, see 8D escape point .
CAPA record vs customer 8D: examples from five sectors
The examples below are illustrative and fictional, not from real cases.
Automotive, stamping (illustrative)
Internal CAPA entry: “Burr on bracket. Cause: worn die. Action: die sharpened.”
What the customer 8D adds: Containment of stock at the customer and in transit, an escape cause for why final inspection missed the burr, and a die maintenance interval.
Evidence to attach: Sort results with quantities, the new maintenance record, and burr checks on the following lots.
Aerospace, machining (illustrative)
Internal CAPA entry: “Wrong hole position. Program corrected.”
What the customer 8D adds: How the wrong program revision reached the machine, why first article inspection did not catch it, and which other parts use the same program release step.
Evidence to attach: The program release record, corrected first article results, and the change to the release step.
Medical devices, assembly (illustrative)
Internal CAPA entry: “Missing label. Operator retrained.”
What the customer 8D adds: A cause beyond the operator, such as a label step that can be skipped, plus a check that would detect a missing label before shipment.
Evidence to attach: The revised work instruction, the added check, and inspection results after the change.
Electronics, PCBA (illustrative)
Internal CAPA entry: “Solder bridging. Stencil cleaned.”
What the customer 8D adds: Containment of boards in stock, the cause of bridging (for example paste or stencil condition), and why test did not catch it.
Evidence to attach: Before-and-after defect data by lot, and the cleaning interval in the process document.
Food, packaging (illustrative)
Internal CAPA entry: “Seal leak complaint. Sealer adjusted.”
What the customer 8D adds: Which batches were affected and held, why the seal check missed it, and how sealer settings are now controlled.
Evidence to attach: Hold and release records, seal test results after the change, and the updated check frequency.
Turning a CAPA record into a customer 8D? Get a free Accept / Conditional / Reject advisory on the report text, with missing evidence named, before it goes out.
8D Gate is a free pre-send readiness advisory. It doesn't replace the customer's decision. We don't store your 8D body in our database; you can delete anytime. Anthropic processes the text for the review.
Write once, use twice
You don’t need two investigations. Run the case in 8D structure from the start, then link the 8D to your CAPA record, or file the 8D as the CAPA record if your system allows it. Check that the CAPA side still records anything your own process needs, such as an effectiveness review date or a decision on similar products.
Where suppliers usually lose points
- Copying a one-line CAPA cause into D4 without evidence or an escape cause.
- Listing containment as the corrective action.
- Closing D6 with “implemented” and no data from after the change.
- Leaving D7 empty because the CAPA form had no field for it.
For D4 rewrites, see weak D4 root cause examples . For D6 evidence, see 8D D6 verification of effectiveness .
Before you send
- The report follows the customer’s 8D format, not only your CAPA form.
- Containment and permanent action are in separate sections.
- D4 has an occurrence cause and an escape cause, each with evidence.
- D6 shows data from after the change, or an open item with a date.
- D7 says which similar products or processes were checked.
- The 8D links to your CAPA record number.
Use the 8D report template for the structure. If the finding came from an audit, see how to answer an audit finding with an 8D . For automotive rules, see IATF 16949 8D requirements .
FAQ
- Is 8D the same as CAPA?
- No. CAPA is the corrective and preventive action process in your quality system. 8D is a structured method and report for one problem. An 8D can be how you carry out and document one CAPA case.
- Which should we use when the customer asks for an 8D?
- Send the 8D in the customer’s format, and link it to your internal CAPA record. Don’t send a CAPA form in place of a requested 8D unless the customer agrees.
- Does 8D Gate check CAPA records?
- It reviews 8D report text as a pre-send readiness check. You get an Accept / Conditional / Reject advisory with missing evidence and questions. It isn’t a customer decision or an audit. The review tool is v0.1: it reviews English 8D reports, and the interface and report are in English. Templates are also available in German, Czech and Polish.
Free pre-send readiness check
Before the report goes out, run the text through the free supplier 8D readiness check.
Paste text or upload PDF, DOCX, or Excel. You get an Accept / Conditional / Reject advisory, a score, section ratings, missing evidence, and questions to close gaps, with a PDF download. It is a pre-send readiness check for your team, not a customer decision.
8D Gate is a free pre-send readiness advisory. It doesn't replace the customer's decision. We don't store your 8D body in our database; you can delete anytime. Anthropic processes the text for the review.
Get the free 8D / D4 checklist
Keep the one-page version next to your CAPA log. It covers D1–D8 and goes deeper on D4 occurrence, escape, and verification.
Get the free 8D / D4 checklist