What's SOP is asked in two completely different situations and the answers barely overlap. In conversation it means what is normal here, and the answer is a custom somebody can describe. At work it usually means where is the written procedure, and the answer should be a link. The gap between the two is where organisational knowledge quietly leaves the building, so this page is about telling them apart.
The idiom: that is SOP around here
Borrowed from the military and used to mean the normal way, usually with a shrug. It carries no implication that anything is written down, and that is precisely the confusion: everybody agrees there is an SOP, nobody has seen it, and the practice exists entirely in the heads of the three people who have always done it.
The document: a link, or it does not exist
The test is asking where it is. If the answer is a link, there is a procedure. If the answer is a description, what exists is a custom with an official-sounding name, and it will leave when the people leave. That is not a small loss: it is the reason handovers take months in organisations that believe they are well documented.
Why the gap costs money
A custom cannot be reviewed, cannot be improved deliberately and cannot be handed over. It also cannot be wrong in any detectable way, which sounds like an advantage and is the opposite: the same job gets done three different ways by three people and nobody finds out until one of them produces a different result.
Closing the gap is smaller than it sounds
Write the short version of the customs people already follow. Most are a page. A small organisation ends up near this site's worked example of 48 documents, and reviewing them once a year at 2.5 hours each is 120 hours, or about ten hours a month, which is a fraction of what one bad handover costs.
Questions people ask about what's sop
What's SOP mean in conversation?
The normal way of doing something, usually with no implication that it is written down anywhere.
How do I tell whether a real SOP exists?
Ask where it is. A link means it exists; a description means it is a custom with an official-sounding name.
Why does the difference matter?
A custom cannot be reviewed, improved or handed over, and it leaves when the people who hold it leave.