SOP Maker › SOP vs work instruction
What is the difference between an SOP and a work instruction?
An SOP describes a whole process from start to finish and says who does what. A work instruction describes one task inside that process and says exactly how to do it.
Both are controlled documents. The difference is scope and depth, not importance.
Take end-of-shift cleaning on a packing line. The SOP covers the lot: when cleaning starts, who isolates the line, which areas get done in which order, which chemicals are approved, who checks it and signs it off. Somewhere in the middle it says "clean the slicer". The work instruction is the one-page document that tells you how to clean that slicer – guard off, blade out, this chemical at this dilution, five minutes contact, rinse, rebuild, check.
You could write all of it into one document. On a small line that's often the right call. It stops being right when the same slicer appears in four different procedures, because now the same instructions exist in four places and three of them will be out of date within a year.
Side by side
| SOP | Work instruction | |
|---|---|---|
| Scope | A whole process, often across roles and shifts | One task, usually one person and one machine |
| Answers | What happens, in what order, and who does it | How to do this one thing, step by step |
| Reader | Anyone involved in the process, including supervisors | The person doing the task, at the machine |
| Length | Two to eight pages is normal | One page, ideally with photographs |
| Detail | Names the control, points to the detail | Is the detail: settings, dilutions, times, torques |
| Changes | When the process changes | When the machine, chemical or tool changes |
| Authorised by | Process owner and the standard owner | Usually the process owner, or the engineer |
| Example | End-of-shift hygiene clean, line 3 | Strip and clean the slicer, line 3 |
Where each one sits
Most sites end up with four layers, whatever they call them:
- Policy – what the company commits to, and why. Rarely changes.
- Procedure or SOP – how a whole process runs, and who's responsible for each part of it.
- Work instruction – how one task inside that process is carried out.
- Records and forms – the signed sheets and checks that prove it happened.
The layers matter because they decide where a change lands. Swap the sanitiser and you update one work instruction. Change who signs off the clean and you update the SOP. If a single change forces you to edit eleven documents, the split is wrong somewhere.
Business instructions, production instructions and production plans
These names aren't standardised, and different sites use them for different things, so it's worth agreeing what yours mean before you argue about them. In general use:
- Business instruction sits at or just under policy level. It's a company-wide rule about how something is handled – expenses, supplier approval, escalation – and is closer to an administrative SOP than to a shop-floor document.
- Production instruction is a work instruction by another name, usually for a manufacturing task: line settings, changeover, a product-specific make-up.
- Production plan isn't a procedure at all. It's a schedule – what gets made, on which line, in what quantity, when. It changes weekly or daily, so it should never be a controlled document with a revision number. Keep it out of your SOP system.
The test is simple. If it describes how something is done, it's a procedure or an instruction and it needs version control. If it describes what's happening this week, it's a plan and it doesn't.
Which one should you write?
Write an SOP when the job crosses roles or shifts, when handovers matter, when you need to fix responsibility, or when an auditor is going to ask how the process is controlled.
Write a work instruction when one task is done the same way everywhere, when it needs settings and photographs, when the person doing it needs one page and not eight, or when the same task turns up in several SOPs and you'd rather maintain it once.
When you're not sure, write the SOP first. It shows you where the detail is heavy, and those heavy spots are exactly where the work instructions want to be pulled out.
Writing either one
SOP Maker builds both. Work Instruction is one of the document formats – scope, method, corrective action, contingency – alongside the fuller SOP formats, and both get the same document-control header, the same numbering and the same printing. The seven-step guide covers the writing itself, and the worked example shows a finished document. The templates page lists what each format starts you with.
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