FIFO & Moving Average Valuation Methods

1. Overview

ERPNext values stock perpetually: every stock movement (receipt, issue, transfer, manufacture) updates the item's quantity and its monetary value in real time through the Stock Ledger. The Valuation Method decides how the value of each outgoing unit is calculated and therefore what your remaining inventory is worth and what your Cost of Goods Sold (COGS) becomes.

ERPNext supports three valuation methods:

• FIFO (First In, First Out)
• Moving Average
• Standard Cost (covered in a separate guide)

This guide explains FIFO and Moving Average — how each works, the accounting they produce, their behavior with backdated entries and reposting, and the pros and cons of each so you can choose the right one per item.

Where to set it: Valuation Method can be set per Item (Item master → Valuation Method), or defaulted at the Company level, or globally in Stock Settings. The most specific setting wins (Item → Company → Stock Settings).

2. FIFO (First In, First Out)

2.1 How it works

FIFO assumes the oldest stock is consumed first. ERPNext maintains a FIFO queue of [quantity, rate] layers for each item-warehouse. Every receipt adds a layer at its actual incoming rate; every issue consumes layers from the front (oldest) of the queue at their original rates.

The valuation rate reported at any moment is the weighted average of the layers currently remaining in the queue, but each outgoing unit is costed at the specific rate of the layer it is drawn from.

2.2 Worked example

At step 3, the 15 issued units are costed as 10 @ 100 + 5 @ 120 = 1,600 (oldest first). The remaining 5 units stay valued at their original 120.

2.3 Accounting impact

In a perpetual-inventory company, the issue posts COGS at the actual layered cost of the consumed units:

• COGS (step 3) = 1,600
• Inventory is credited 1,600; remaining inventory asset = 600.

Because outgoing cost reflects the actual historical purchase price of the specific units leaving stock, FIFO closely tracks real acquisition cost and is widely accepted for statutory/tax reporting.

2.4 Pros

• Closely matches actual cost flow — the cost of goods sold reflects the genuine price paid for the specific units consumed.
• Realistic ending inventory value — remaining stock is valued at the most recent purchase prices, so the balance sheet reflects current replacement-ish cost.
• Widely accepted for accounting standards and tax authorities; intuitive and auditable (you can trace which layers were consumed).
• Good for items with shelf life / lot rotation (food, pharma, perishables) where you physically issue oldest-first anyway.

2.5 Cons

• Sensitive to backdated entries — inserting or editing a past transaction changes which layers later issues consume, so every subsequent ledger entry must be recomputed (reposted). On long, dense ledgers this reposting is slow and resource-intensive.
• Volatile COGS in rising-price environments — older, cheaper layers are expensed first, which can understate COGS and overstate profit during inflation.
• More computation / storage — the layer queue must be maintained and serialized for every item-warehouse.
• Heavier reposting load when corrections, cancellations, or landed-cost vouchers touch historical entries.

3. Moving Average

3.1 How it works

Moving Average maintains a single blended average rate per item-warehouse. On every receipt, the average is recomputed:

new average = (existing qty × existing avg rate + incoming qty × incoming rate)
              ──────────────────────────────────────────────────────────────
                             existing qty + incoming qty

Issues are costed at the current average rate and do not change the average; only receipts (and revaluations) move it.

3.2 Worked example

At step 2 the average becomes (10×100 + 10×120) / 20 = 110. The 15 issued units at step 3 are each costed at 110 → COGS = 1,650; remaining 5 units valued at 110 = 550.

3.3 Accounting impact

• COGS (step 3) = 1,650 (15 × average 110).
• Inventory credited 1,650; remaining inventory asset = 550.

Compared with FIFO on the same data, Moving Average smooths the cost: COGS is 1,650 vs FIFO's 1,600, and the difference flows into the value of remaining stock.

3.4 Pros

• Smooths out price fluctuations — a single blended rate dampens the impact of volatile purchase prices, giving steadier COGS and margins.
• Simpler and lighter — only one rate per item-warehouse to maintain; no layer queue to store or walk.
• Easier to understand and reconcile — "one item, one current cost" is intuitive for operations and reporting.
• Good for homogeneous, fast-moving, commoditized items where individual lots are indistinguishable (bulk fasteners, fuel, raw chemicals).

3.5 Cons

• Still requires reposting on backdated entries — because a past receipt changes the running average for all later transactions, ERPNext must recompute the forward chain. Like FIFO, this can be slow on long ledgers.
• Does not track actual lot cost — outgoing cost is a blend, so it can diverge from the real price paid for the specific units shipped; less precise for lot-traceable or high-value items.
• Average can lag reality — in fast-moving price environments the blended rate trails current market cost, which may misstate margins on individual sales.
• Less granular audit trail — you cannot point to "these specific units left at this specific cost," only to the average at that time.

4. FIFO vs Moving Average — at a glance

5. The shared limitation: backdated entries trigger reposting

This is the most important operational characteristic both methods share — and the key contrast with Standard Cost.

With both FIFO and Moving Average, the value of any stock ledger entry depends on the entries before it (which layers exist, or what the running average is). So when you:

• insert a backdated transaction,
• cancel or amend a historical voucher,
• apply a Landed Cost Voucher to a past receipt, or
• change a past valuation rate,

…ERPNext must repost — recompute the quantity, rate, value, and GL impact of every subsequent stock ledger entry for that item-warehouse (a Repost Item Valuation job). On items with long, dense histories this is slow, resource-heavy, and temporarily changes the value of stock you considered settled.

If your organization frequently records backdated corrections and this reposting cost is painful, consider the Standard Cost method (see the separate Standard Valuation Rate guide), where the rate is known by date and backdated entries do not trigger reposting.

6. Choosing a method — recommendations

Best practices (both methods)

• Set the method before the item transacts. Changing an item's valuation method while stock exists is disruptive and may be blocked.
• Enable perpetual inventory accounts (warehouse/stock, stock-received-but-not-billed, COGS, stock adjustment) so valuation and GL stay in lock-step.
• Batch your historical corrections and run them in low-traffic windows, since they trigger reposting.
• Use Landed Cost Vouchers promptly after receipt to avoid large retroactive revaluations later.
• Reconcile stock value vs. GL periodically (Stock Ledger / Stock Balance vs. the inventory account) to catch drift early.
• Be consistent per item category so reporting and margins are comparable across similar items.

7. Summary

• FIFO costs outgoing stock at the actual rate of the oldest remaining layer — precise, audit-friendly, ideal for perishables and lot-traceable goods, but layer-heavy and reposting-sensitive.
• Moving Average costs outgoing stock at a single blended rate — simple, smooth, ideal for commoditized high-volume items, but less precise and still reposting-sensitive.
• Both recompute (repost) the forward ledger when the past changes. If that cost is the deciding factor, the Standard Cost method avoids it entirely — see the Standard Valuation Rate guide.