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Guide · Pricing & Margin

Minimum Order Quantity: Unit Price vs. Cash Cost

Evaluate supplier minimums using expected sales, leftover inventory, ordering costs, and cash required rather than invoice unit price alone.

By PriceAndProfit Editorial Updated 3 min read

On this page
  1. Worked calculation
  2. Decision checks and limits
  3. Apply the calculation

A lower supplier unit price can require a larger cash commitment and leave more inventory unsold. Minimum order quantity therefore belongs in a purchasing scenario, not just a unit-cost comparison. Start with a defined demand horizon and distinguish units purchased, units expected to sell, and units remaining. The leftover stock may have value, but that value should be an explicit assumption rather than an automatic profit benefit.

Worked calculation

Initial cash required = order quantity × supplier unit price + inbound charges; remaining inventory units = purchased units − units sold

Assume option A supplies 300 units at $12 each with $120 inbound freight. The initial cash requirement is $3,720, and landed cost is $12.40 per unit. Option B requires 600 units at $10.50 each with $180 freight. It needs $6,480 upfront and has a lower landed cost of $10.80. If expected sales over the planning horizon are 300 units, option B commits an additional $2,760 of cash while leaving 300 units on hand.

At a $25 selling price and ignoring identical selling costs, the first 300 sales under option A generate $7,500 revenue and $3,780 gross profit. Using option B's landed cost, those sales show $4,260 gross profit, $480 more, with $3,240 of modeled inventory cost remaining. The improved reported margin does not mean the business has recovered the additional purchase payment. Cash available after the receipts and initial purchase is $3,780 for A versus $1,020 for B.

Hypothetical worked example
OptionUnits boughtInitial cashLanded unit costStock after 300 sales
A 300 $3,720 $12.40 0 units
B 600 $6,480 $10.80 300 units

Decision checks and limits

If all 600 units will eventually sell, option B may compare favorably with buying two 300-unit orders under unchanged terms. Two A orders would cost $7,440 in total, versus $6,480 for B, a $960 difference before storage, damage, obsolescence, and timing costs. But future demand, future supplier prices, and the need for a second order are uncertain. Show the 300-unit and 600-unit outcomes instead of assuming the larger forecast is assured.

Avoid dividing the entire large-order purchase by the first 300 sales and calling that an accounting unit cost. That calculation can be useful as a cash-recovery threshold, but it answers a different question. Similarly, do not omit unused stock from the cash plan because it remains an asset. Review physical storage limits, shelf life where relevant, supplier reliability, and the ability to reorder. A purchasing decision needs both a feasible cash schedule and a realistic plan for the inventory beyond the first sales period.

Apply the calculation

  1. Set a sales horizon

    Use an explicit demand range and identify when another order would actually be required under the smaller option.

  2. Show inventory and cash together

    Calculate gross profit on units sold, remaining inventory cost, and the initial purchase payment as separate results.

  3. Stress-test leftovers

    Consider a slower selling period, additional storage, and a discounted exit for residual stock without presenting those assumptions as certain outcomes.

Method references: OpenStax: Relevant information for decisions. Accessed October 22, 2026. All dollar figures are hypothetical worked examples.

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