Everything You Should Know About Inventory Allocation

What Is Inventory Allocation?

Inventory allocation is the process of assigning available stock to specific orders, customers, sales channels or locations, according to rules you set in advance. It answers three practical questions every distribution and retail business faces daily: how much stock is truly free to promise, where should it sit, and who gets it first when there is not enough for everyone.

Without clear allocation, two salespeople can promise the same 200 units to two different customers within minutes of each other, an online store can sell stock that is already committed to a wholesale contract, and a branch can run out while another warehouse holds months of cover. The stock exists, but the commitments made against it do not match reality.

This guide explains the core concepts, the main allocation methods, priority rules for shortages, a full worked example, and how to set allocation up in an ERP system. Figures in the examples are hypothetical.

Key Terms

The most common mistake is to let sales teams promise against on-hand stock rather than available or ATP. On-hand includes units already committed to other customers.

Available to Promise in Practice

ATP looks forward in time. Suppose an item has 600 units on hand today and the following confirmed commitments and expected receipts:

If a customer asks today for 200 units, the honest answer is: 30 units can be promised for delivery before day 9 without breaking another commitment, and the remaining 170 from day 9 once the purchase order arrives. A system that shows only "600 on hand" would invite the salesperson to promise all 200 immediately and create a shortage for the order due on day 5 or day 12.

ATP depends on reliable expected receipt dates. If purchase orders routinely arrive late, ATP will be too optimistic. Supplier lead time performance and ATP accuracy are linked.

Allocation Methods

Hard allocation

Specific units are reserved for a specific order and cannot be used for anything else until the order ships or is cancelled. Some companies also physically move the goods to a staging area. Hard allocation suits confirmed and paid orders, contract commitments, project materials and scarce items.

Soft allocation

Stock is earmarked but can be reassigned if a higher-priority demand appears before a cut-off point. It suits quotations, orders awaiting credit approval and seasonal pre-positioning. A quotation might soft-reserve stock for its validity period, say seven days, after which the reservation lapses automatically.

Channel allocation

A fixed quantity or percentage of stock is ring-fenced for each sales channel, for example 60% wholesale, 25% branches and 15% online. This prevents one fast channel from draining stock that another has committed to support. The ring-fences should be reviewed regularly and released when one channel clearly cannot use its share.

Location allocation

Incoming stock is divided between warehouses or branches based on their demand, cover and lead time. If Riyadh sells 45% of an item, Jeddah 30% and Dammam 25%, a container of 1,000 units would not be split evenly; it would follow demand, adjusted for each location's current stock.

Batch and expiry allocation

For goods with batches and expiry dates, allocation must also decide which batch goes to which order. First-expiry-first-out is the usual rule, but some customers, such as large retailers, require a minimum remaining shelf life on delivery. The allocation must respect that, or the delivery will be rejected at the customer's dock.

Priority Rules When Stock Is Short

When demand exceeds supply, someone decides who waits. Without agreed rules, that decision is made by whoever shouts loudest or calls the warehouse first. Common rules include:

• First come, first served: by order date and time. Simple and transparent, but ignores customer value and contract terms.
• Customer tier: strategic or contracted customers first, then others. Must be defined in advance and recorded on the customer record.
• Delivery date: orders with the earliest promised date first, so commitments are met in sequence.
• Fair share: each order receives the same proportion of its requested quantity. Useful when you want to keep all customers partly served during a temporary shortage.
• Margin: highest-margin orders first. Commercially logical in the short run, but risky if applied without regard to relationships.

Most companies combine rules: contracts first, then by delivery date within each tier, with fair share applied to the remaining customers in a severe shortage.

A Worked Example

A hypothetical FMCG distributor in Dammam receives 1,000 cartons of a fast-selling item after a supplier delay. Open demand totals 1,600 cartons:

The company's allocation policy is: contracted customers in full first, then fair share for the rest.

1. Order A receives its full 500 cartons. Remaining stock: 500.
2. Remaining demand from B, C and D is 400 + 450 + 250 = 1,100. The fair share ratio is 500 ÷ 1,100, about 45.5%.
3. B receives about 182 cartons, C about 205 and D about 113, rounded to whole cartons so the total stays at 500.
4. The unfilled balances, 218 for B, 245 for C and 137 for D, become backorders against the next purchase order, with new dates communicated to each customer.

The key point is not the specific rule. It is that the rule was decided before the shortage, configured in the system, and applied consistently, so the sales team could explain it to customers.

Allocating Across Warehouses

For companies with several locations, the question is not only who gets stock but where it should be. A practical method for distributing a new receipt:

1. Calculate each location's expected demand until the next replenishment.
2. Subtract its current available stock and any stock in transit to it.
3. Add its safety stock target.
4. The result is each location's net need. Allocate the receipt in proportion to these needs, capped by available warehouse space.

For example, if Riyadh needs 420 units, Jeddah 260 and Dammam 120, and the receipt is 700 units, allocating in proportion to the 800 units of total need gives Riyadh about 368, Jeddah about 227 and Dammam about 105. Transfers later between locations cost money, so getting the first split right matters. Our guide to safety stock explains how to set the buffer each location needs.

Omnichannel Allocation

Companies that sell through branches, wholesale and an online store face a specific problem: each channel sees stock through a different system or screen, often with a time lag. An online store that updates stock every few hours can sell units already sold in a branch.

The fix has three parts. First, one inventory record, with every channel reading available stock from the same source. Second, channel ring-fences or buffers, so the online store is shown slightly less than true availability to absorb timing gaps. Third, frequent synchronisation of orders back into the ERP so allocations are made as soon as orders are placed. Our article on omnichannel retail with ERP covers this in more detail.

Allocation Beyond Sales Orders

Allocation is often discussed only in terms of customer orders, but the same logic applies to internal demand.

Production orders

In manufacturing, components are allocated to production orders when they are released, based on the bill of materials. If a shared component is not reserved, two production orders can start on the assumption that the same material is available, and one will stop halfway. Reserving components at release, and checking availability before release, keeps the floor schedule realistic.

Projects and contracts

Contractors often buy materials for a specific project and need them protected until installation. Reserving stock against the project, rather than leaving it in general inventory, prevents a site supervisor from borrowing materials for another job and leaving the original project short. The reservation also supports accurate project costing because the material is issued to the right project when used.

Service and spare parts

Companies that maintain equipment for customers under warranty or service contracts may hold spare parts reserved for those obligations. Treating them as freely available sales stock risks breaking a service commitment to make a one-off sale.

Allocation and Credit Control

Allocation and credit approval interact. If stock is hard-reserved for an order from a customer who is over their credit limit, the stock sits blocked while finance and sales discuss the account, and other customers may be refused in the meantime. A cleaner approach is to soft-reserve orders on credit hold for a limited time, typically one or two working days, and to convert them to hard reservations only once the hold is released. If the hold is not cleared within the period, the reservation lapses and the stock returns to available. This keeps credit decisions from silently freezing inventory.

The same principle applies to orders waiting for advance payment. Under Saudi VAT rules, an advance received before delivery is taxed when it is received, so finance will usually record the payment promptly; linking that receipt to the order is the natural trigger to firm up the reservation.

Measures to Track

Common Mistakes

• Promising against on-hand: the most frequent cause of overselling.
• Never releasing reservations: cancelled quotations and abandoned orders keep stock locked. Set automatic expiry for soft allocations.
• Priority by phone call: undocumented exceptions undermine trust in the rules.
• Ignoring stock on hold: damaged or quarantined goods counted as available.
• Static channel ring-fences: splits set once and never reviewed leave stock idle in a slow channel.
• Unreliable receipt dates: ATP built on purchase orders that always arrive late.

Setting Up Allocation in an ERP

A practical sequence for implementing allocation rules:

1. Clean the base: accurate on-hand balances by location, hold statuses for damaged or quarantined stock, and reliable expected dates on open purchase orders.
2. Define the policy in writing: which orders reserve stock and when, soft reservation validity, customer tiers, and the shortage rule.
3. Configure: reservation on order confirmation, expiry of soft reservations, customer tier field, channel buffers.
4. Train sales and customer service: they must quote from available and ATP, not on-hand.
5. Review monthly: fill rate, oversells, stale allocations and backorders, then adjust rules.

How Tranquil ERP Supports Allocation

Tranquil's sales module covers quotations, invoices, deliveries, returns and customer records, and its inventory module supports central inventory across locations and multiple units of measure, all sharing one database with purchasing and accounting. That means orders, stock balances and expected receipts sit in one place. Where you need specific reservation rules, customer tiers or channel buffers, Tranquil's customisation services cover screens, reports, approvals and API integrations, for example with an online store. See the inventory management and order management pages, and our guide to backordering for handling unfilled demand. To discuss your setup, contact the Tranquil team.

Frequently Asked Questions

What is the difference between on-hand and available stock?

On-hand is everything physically in the warehouse according to the system. Available is on-hand minus stock already allocated to confirmed orders and minus stock on hold. Promises to customers should be based on available stock or ATP.

When should stock be reserved for an order?

Most companies hard-reserve at order confirmation, and soft-reserve for quotations or orders awaiting credit approval. Soft reservations should expire automatically after a set period.

Which shortage rule is best?

There is no single best rule. Many companies serve contracted customers first, then allocate by promised date or fair share. What matters most is agreeing the rule in advance and applying it consistently.

How does allocation work with expiry dates?

The system allocates specific batches, usually by first-expiry-first-out, while respecting any minimum remaining shelf life a customer requires on delivery.

Does allocation reduce inventory levels?

Indirectly. Better allocation means stock is in the right place and committed accurately, which reduces emergency purchases, inter-warehouse transfers and the extra buffer people hold because they do not trust the numbers.