SOP vs Work Instruction: Difference and Example
Jure Špeh, Co-founder and CTO
SOPs and work instructions are often confused or merged into one document. This guide explains the real difference, when to use each, and shows a clear real-world example that actually works in operations.
30-second summary
SOPs define rules and intent.
Work instructions define execution.
If one document tries to do both, operators ignore it and auditors still complain.
This article explains the difference without theory overload and shows a real operational example.
The real problem: SOP vs work instruction confusion
Most companies don’t fail because they lack documentation.
They fail because their documentation is unusable.
Common symptoms:
- One giant “SOP” nobody reads
- Operators asking supervisors instead of following documents
- Training taking too long
- Auditors asking for clarification despite “documented procedures”
The root cause is simple:
SOPs and work instructions are mixed into the same document.
What an SOP actually is
An SOP (Standard Operating Procedure) is a governance document.
Its job is to define what must happen and under which rules.
An SOP answers:
- What process exists
- Why it exists
- When it applies
- Who is responsible
- Which standards, safety rules, or regulations apply
An SOP is not meant to be followed step-by-step on the shop floor.
SOP example (correct level)
SOP: Injection Molding Machine Setup
- Purpose: Ensure consistent setup before production
- Scope: All operators on Line A
- Responsibility: Shift supervisor verifies completion
- Preconditions:
- Correct mold selected
- Approved production order available
- Safety:
- Lockout/tagout mandatory
- References:
- WI-IM-01 Install mold
- WI-IM-02 Set parameters
- WI-IM-03 First-piece inspection
This is enough for audits, compliance, and management.
It is useless for execution. That is intentional.
What a work instruction actually is
A work instruction is an execution document.
Its job is to help a person perform a task correctly, every time.
A work instruction answers:
- How to do the task
- In which order
- With which tools
- With which settings
- What to check before moving on
Work instruction example (correct level)
WI-IM-01: Install Injection Mold
- Power off machine and apply lockout
- Open safety guard
- Attach crane hook to mold
- Align mold with mounting plate
- Tighten bolts to 120 Nm
- Connect cooling lines (blue → inlet, red → outlet)
- Close guard and remove lockout
This is what operators actually follow.
SOP vs work instruction: clear comparison
| Dimension | SOP | Work Instruction |
|---|---|---|
| Purpose | Define rules and intent | Enable correct execution |
| Level | High-level | Step-by-step |
| Audience | Management, QA, auditors | Operators, technicians |
| Change frequency | Low | High |
| Format | Text, references | Steps, images, video |
| Usable alone on shop floor | No | Yes |
If your SOP contains screenshots and step numbers, it is not an SOP.
Correct hierarchy (this is what auditors expect)
- Policy (optional, company-wide)
- SOP (process rules)
- Work instructions (task execution)
One SOP usually links to multiple work instructions.
This structure scales.
A single-document approach does not.
Practical example: machine changeover
Wrong structure (very common)
- One 18-page “SOP”
- Includes policy text, screenshots, steps, notes
- Nobody updates it
- Operators rely on tribal knowledge
Correct structure
SOP: Changeover – Line A
- When changeover is required
- Safety and responsibilities
- Acceptance criteria
- Links to work instructions
Work instructions
- WI-01 Remove old mold
- WI-02 Clean machine
- WI-03 Install new mold
- WI-04 Set parameters
- WI-05 First-piece inspection
Operators open only what they need.
Auditors review the SOP.
Training becomes faster.
Format matters more than people admit
SOPs should be:
- stable
- boring
- text-focused
- easy to audit
Work instructions should be:
- visual
- short
- task-focused
- usable while working
Trying to make one document serve both purposes guarantees failure.
Where video fits (and where it doesn’t)
Video is excellent for work instructions, not raw SOPs.
Video captures:
- hand movements
- timing
- machine feedback
- real exceptions
But raw video is:
- not searchable
- not scannable
- not auditable
That is why high-performing teams convert videos into structured work instructions and link them to SOPs.
SOPs and work instructions with AI
Modern tools like TagPlan AI change how work instructions are created:
- Record real work once
- Convert video into structured steps
- Add safety notes automatically
- Translate into multiple languages
- Link instructions directly to SOPs
SOPs stay stable.
Work instructions stay current.
This is the missing link in most documentation systems.
When to use what
Use an SOP when:
- defining rules
- ensuring compliance
- passing audits
- standardizing processes
Use work instructions when:
- training operators
- reducing errors
- onboarding new staff
- ensuring repeatable execution
You need both.
Replacing one with the other is a category error.
Frequently Asked Questions
Can one SOP reference many work instructions?
Yes. That is the correct structure.
Should SOPs include images or videos?
No. Link to work instructions instead.
Which one changes more often?
Work instructions. Processes change slower than execution details.
Early access
If your SOPs exist but execution still varies, the problem is not discipline.
It is missing or outdated work instructions.
TagPlan AI helps teams turn real process videos into structured, up-to-date work instructions linked to SOPs.
