Unit Cost Economics

Cost Per Order Calculator

Separate fixed monthly operating overhead from direct variable costs to calculate your fully burdened cost per order.

Monthly Fixed Overhead & Order Volume

Fixed Overhead / Order$2.00
Variable Fulfillment / Order$3.00
Ad Spend / Order$2.00
Total Cost per Order$7.00
Quick Answer: How do you calculate total cost per order including fixed overhead?

To calculate total cost per order, divide your monthly fixed business overhead (rent, software subscriptions, staff salaries) by your monthly order volume, then add variable per-order costs (COGS, packaging, postage, transaction fees, and ad CAC). Total cost per order = (Fixed Overhead / Monthly Orders) + Variable Cost per Order.

What the Cost Per Order Calculator Does

Evaluating order profitability based purely on direct variable costs (COGS, shipping, transaction fees) ignores the monthly fixed operating overhead required to run your business. Software subscriptions, warehouse rent, customer support salaries, and utility bills must be absorbed by your sales volume.

The MerchSites Cost Per Order Calculator separates monthly fixed overhead allocation from direct variable order expenses. It calculates your true fully burdened cost per order, minimum required order value, and net profit contribution.

Who Should Use This Calculator

Essential for store founders, operations managers, and financial analysts:

Growing Ecommerce Brands

Stores scaling order volume who need to know how monthly fixed overhead per order drops as sales volume expands.

3PL & Warehouse Operators

Fulfillment centers and merchants analyzing pick, pack, and storage costs per shipped parcel.

Fixed Overhead Allocation vs Variable Fulfillment Costs

1. Fixed Monthly Overhead:

Shopify/Etsy subscriptions, apps, office/warehouse rent, fixed staff salaries, insurance, legal.

Allocated per order: Total Monthly Fixed / Monthly Orders.

2. Variable Order Costs:

Product COGS, landed shipping, poly mailers, card fees, return reserves, paid ad CAC.

Incurred strictly when an order is placed.

Worked Example: $4,500 Monthly Fixed Overhead Store

An online brand incurs $4,500.00 in monthly fixed operating overhead (Shopify plan, 12 apps, virtual assistant, warehouse storage) and ships 500 orders per month. Average retail cart size is $45.00.

Monthly Fixed Operating Overhead ($4,500 / 500 orders):$9.00 per order
Product COGS & Packaging:$12.50
Outbound Shipping Postage & Fees:$6.20
Payment Processing Fee (2.9% + $0.30):$1.61
Direct Variable Cost per Order:$20.31
Fully Burdened Total Cost per Order ($9.00 Fixed + $20.31 Variable):$29.31 Total Cost per Order

Common Unit Accounting Errors

Treating Fixed Overhead as Variable Costs: Fixed monthly bills do not increase with every single sale, but low order volume inflates the fixed cost burden per order.

Frequently Asked Questions

How do I allocate monthly fixed costs to individual orders?

Divide your total monthly fixed expenses (rent, SaaS apps, fixed salaries) by your average monthly order volume.

Last Updated: July 2026

Financial Disclaimer: MerchSites tools and guides provide estimates for product pricing, margin analysis, and expense planning. All calculations are performed locally in your web browser. Content is for educational purposes and does not constitute formal tax, legal, or accounting advice.