Every inventory implementation asks you to pick a valuation method early, usually as a configuration field with three options and no explanation. It looks like a technical setting. It is a policy decision that changes what your business appears to earn.
It also changes your opening balances, which is why it has to be settled before migration rather than after. Changing method on a live system means recalculating history, restating positions and, in practice, migrating stock a second time.
What each method actually does
Standard cost values every unit at a planned figure you set and review periodically. Differences between plan and actual land in a variance account. It makes margin stable and comparable, and it makes variance analysis the mechanism by which you learn anything. It suits manufacturing with repeatable products and reasonably stable inputs.
Moving average revalues the whole on-hand quantity each time you receive stock at a new price. It tracks reality closely with little maintenance, which is why most distributors land here. Its weakness is that a single mispriced receipt silently shifts the value of everything on hand, and finding that later is genuinely unpleasant.
FIFO keeps each receipt as its own layer and consumes the oldest first. It is the most faithful to what physically happened and the most demanding operationally, because the layers have to be maintained accurately for it to mean anything. It suits businesses with volatile input prices or where cost traceability per batch is a requirement rather than a nicety.
The method is not the decision. The decision is what you want to be able to explain at the end of a period, and to whom.
Implementation lead, AxonRaysFour questions that decide it
How volatile are your input costs? If a key material moves more than about ten per cent within a quarter, standard cost will generate variance faster than anyone can analyse it.
Do you need cost per batch? If a regulator, a customer contract or a recall process requires it, that points at FIFO or full batch valuation regardless of what is convenient.
Who explains margin, and to whom? If a board wants comparable monthly margin, standard cost delivers that. If a lender wants balance-sheet realism, moving average or FIFO is closer to it.
Who will maintain it? Standard cost needs someone to review the standards. FIFO needs disciplined layer management. Moving average needs the least attention and gives the least insight.
The three mistakes we see
Choosing what the old system did, without checking whether it worked. Continuity is a reasonable default and a bad reason on its own. If nobody could explain last year’s stock variance, continuity preserves the problem.
Mixing methods without a rule. Different methods per item category can be perfectly valid — raw materials on moving average, finished goods on standard. What is not valid is arriving there by accident, item by item, with no documented rule.
Leaving overhead absorption undecided. The valuation method tells you how to value a receipt. It does not tell you which costs belong in inventory. Freight, duty, handling and production overhead each need an explicit answer, and those answers move margin as much as the method does.
Settle it in one meeting, then write it down
Put finance and operations in a room together, work the four questions above, and record the decision with the reasoning attached. One page. The reasoning matters more than the choice, because in two years someone will ask why, and "it was the default" is how a restatement begins.
Then load the opening balances against that method and reconcile them before anything else moves. Getting this right costs a meeting. Getting it wrong costs a migration.