SOP guide

How to Write an SOP (Standard Operating Procedure)

The sections a controlled SOP needs, a simple method for writing one, and the tips that make it audit-ready.

A Standard Operating Procedure (SOP) is a controlled document that tells your team exactly how to perform a task the same way every time. Good SOPs make training faster, keep quality consistent, and are the backbone of ISO 9001, AS9100, and IATF 16949 certification.

The standard SOP sections

Most audit-ready SOPs follow the same structure:

• Purpose — why the procedure exists and what it ensures.
• Scope — what and where it applies, and any exclusions.
• Responsibilities — which roles do what (Operator, Inspector, Supervisor).
• Materials & equipment — tools, gauges, forms, and references.
• Procedure — numbered, single-action steps in sequence, including verification and record-keeping.
• Safety & PPE — hazards and required controls.
• Records — the forms and records the procedure creates or references.
• Revision history — document number, revision, effective date, and approvals.

How to write one, step by step

1. Define the task and its boundaries. One SOP, one process. Write the purpose and scope first.
2. Map the real steps. Walk the process and capture what actually happens, in order.
3. Write each step as a single instruction in the imperative ("Record the caliper ID", not "the ID should be recorded"). Add verification and record steps where a real process would.
4. Assign responsibilities to real roles, and list the equipment and records.
5. Add the document-control block — number, revision, effective date, approvals — so it's a controlled document.
6. Review and approve with the process owner before it goes live.

Tips

• Keep values you don't know as clear placeholders for the process owner to confirm — never invent torque specs or tolerances.
• One action per step. If a step has an "and", it's probably two steps.
• Include how the step is verified and what record it produces.

← Back to Dropfeed