Ecommerce Accounting: What Your Bookkeeper Isn't Telling You
Your P&L says you're profitable. Your bank account disagrees. Here's what ecommerce accounting actually needs to track — and why standard bookkeeping misses the metrics that matter.
Jakob Sperber
Director
Finance
/
Your P&L says you're profitable. Your bank account disagrees. You're not imagining it — there's a gap, and it's costing you more than you think.
Most ecommerce founders rely on their bookkeeper to tell them how the business is going. The problem isn't that your bookkeeper is bad at their job. It's that their job isn't what you think it is.
Compliance Accounting vs Management Accounting
Your bookkeeper does compliance accounting. BAS lodgements, tax returns, bank reconciliations, payroll. That's the stuff the ATO requires. It keeps you legal. It does not keep you informed.
What ecommerce founders actually need is management accounting — the numbers that drive decisions. How much can you afford to spend acquiring a customer? What's your real margin after every variable cost is accounted for? Which channel is actually profitable when you include all the costs it generates?
Compliance accounting looks backwards. Management accounting looks forward. You need both, but most brands only have one.
What Your Bookkeeper Typically Gets Wrong
This isn't about blame. Bookkeepers are trained in general accounting principles. Ecommerce has specific cost structures that don't fit neatly into standard chart-of-accounts templates. Here's where the numbers go sideways.
Shipping Classified as a Fixed Cost
Shipping is a variable cost. It scales with every order. Yet it routinely gets lumped into "Freight & Courier" as an overhead line item, sitting below gross profit on the P&L. This flatters your gross margin and hides the true cost of fulfilling an order.
If you're paying $9 per order in shipping and doing 3,000 orders a month, that's $27,000 that should be sitting above your contribution margin — not buried in overheads.
Returns Not Netted Against Revenue
Returns are messy in ecommerce. A customer buys in March, returns in April. Your March revenue looks great. Your April revenue looks soft. Neither month tells the truth.
Returns need to be tracked as a percentage of gross revenue and deducted properly to arrive at net revenue. A 15% return rate on a fashion brand can turn a 60% gross margin into a 45% effective margin. That's the difference between a healthy business and one that's quietly bleeding cash.
Marketplace Fees Buried in "Platform Costs"
Selling on Amazon, The Iconic, or Catch? Those marketplace commissions — typically 10–20% of the sale price — are a direct cost of that revenue. They should be treated the same way you treat COGS: deducted before you calculate margin on that channel.
When marketplace fees get buried in a generic "Software & Platforms" category alongside your Shopify subscription and Klaviyo bill, you lose all visibility into channel-level profitability. You might be losing money on every marketplace sale and not know it.
Payment Processing Fees Ignored in Margin Calculations
Stripe, PayPal, Afterpay, Shopify Payments — they all take a cut. Usually 1.5–3% of transaction value. On a $100 AOV, that's $1.50–$3.00 per order. It's not a rounding error. It's a variable cost that belongs in your contribution margin calculation, not tucked away in bank fees.
Ad Spend Treated as One Lump Sum
Your bookkeeper sees a Meta charge and books it to "Advertising." A Google charge goes to the same line. Maybe TikTok too. One number. No distinction between channels, between prospecting and retargeting, between spend on new customers and spend on returning ones.
This is useless for decision-making. You need ad spend broken out by channel at minimum, and ideally separated by new customer acquisition vs returning customer campaigns. The economics are completely different.
The Management P&L for Ecommerce
Standard P&L structures were designed for traditional businesses. Ecommerce needs a layered contribution margin model. Here's the structure that actually works:
Gross Revenue — total sales before any deductions
Minus returns, refunds, and discounts = Net Revenue
Minus COGS (landed product cost) = Gross Profit (CM1)
Minus Variable Costs (shipping, payment processing, pick & pack, packaging, marketplace fees) = CM2
Minus Marketing (ad spend, influencers, affiliates) = CM3
Minus Fixed Costs (rent, salaries, software, insurance) = Net Profit
This isn't academic. Each layer tells you something specific.
CM2 is the money available to spend on marketing. If CM2 is $35 per order, that's your ceiling for customer acquisition cost before you go backwards. It's the most important number for any ecommerce founder running paid acquisition.
CM3 is what the business actually keeps per order after acquisition. It tells you whether growth is profitable or whether you're buying revenue at a loss.
We break this model down in detail in our guide to ecommerce unit economics and the CM1–CM2–CM3 framework. If you haven't read it, start there.
Inventory Accounting: Where COGS Goes Wrong
COGS is the foundation of every margin calculation. Get it wrong and everything downstream is wrong too. Most ecommerce brands get it wrong.
Landed Cost, Not Invoice Cost
Your product cost isn't just what your supplier invoiced you. Landed cost includes freight to Australia, customs duties, import GST, inspection fees, warehousing on arrival — everything it takes to get that product onto a shelf ready to sell.
If your supplier invoice says $12 per unit but freight, duties and handling add another $4, your true COGS is $16. That's a 33% difference. Every margin calculation using $12 is fiction.
FIFO vs Weighted Average
When your product cost changes between purchase orders — and it always does, thanks to exchange rates, shipping costs and supplier pricing — you need a consistent method for valuing inventory.
FIFO (First In, First Out) assumes you sell the oldest inventory first. Weighted Average Cost blends all purchases together. Both are valid. The problem is when brands use neither consistently, or when their bookkeeper uses one method and their inventory system uses another.
Pick a method. Apply it consistently. Make sure your accounting software and your inventory management system agree.
Cash vs Accrual: It Matters More Than You Think
Most ecommerce brands under $2M use cash accounting because it's simpler and their accountant recommended it. Cash accounting records revenue when money hits your bank and expenses when money leaves.
The problem? Ecommerce has significant timing gaps. You pay for inventory months before you sell it. You collect revenue from a November sale but process the return in January. You pay for ads in real-time but the revenue they generate trickles in over weeks.
Accrual accounting matches revenue and costs to the period they actually relate to. It gives a far more accurate picture of profitability, especially for brands with long inventory cycles or high return rates.
At minimum, you should understand the difference and know which method you're using. Ideally, you're running accrual for management reporting even if you file taxes on a cash basis. For a deeper look at how cash timing affects ecommerce businesses, see our piece on the real numbers behind ecommerce cash flow.
The Metrics Your Bookkeeper Won't Calculate
These sit in the gap between accounting and growth strategy. Your bookkeeper won't produce them. Your ad platform can't calculate them accurately. But they're the numbers that determine whether your business scales or stalls.
CM2 Per Order
Your contribution margin after all variable costs but before marketing. This is your acquisition budget ceiling. If you don't know this number, you're guessing on ad spend.
New Customer CAC
Cost to acquire a new customer, not a blended average across new and returning. Blended CAC is misleading because returning customers are cheap to convert. You need to know what it costs to bring someone in for the first time.
CAC Payback Period
How many days or months until a new customer's cumulative contribution margin repays the cost of acquiring them. If your CAC payback is 90 days but your cash cycle is 60 days, you have a funding gap that no amount of revenue growth will fix.
MER (Marketing Efficiency Ratio)
Total revenue divided by total marketing spend — and you need to know your allowable MER alongside it. It's a blunt instrument but it's useful as a top-level health check. Unlike platform-reported ROAS, MER uses real revenue from your accounting system — not inflated, double-counted attribution numbers from Meta.
60-Day Lifetime Gross Profit (LTGP)
The total gross profit a customer generates in their first 60 days. This tells you whether your repeat purchase rate is strong enough to justify higher upfront acquisition costs. A brand with a 40% 60-day repurchase rate can afford a much higher CAC than one with 5%.
The Tool Stack Gap
Most ecommerce brands end up with three layers of financial tools:
Compliance accounting: Xero or MYOB. Handles BAS, tax, bank reconciliation. Good at what it does. Not built for ecommerce margin analysis.
Inventory management: Dear (now Cin7 Core), Cin7 Omni, or similar. Tracks stock levels, purchase orders, landed costs. Essential for accurate COGS — but only if set up properly.
Marketing-finance metrics: Triple Whale, Lifetimely, or Polar Analytics. Pulls order data and ad spend together to calculate CAC, LTV, MER and contribution margins.
The problem is the gap between these systems. Xero doesn't talk to Triple Whale. Your inventory system might feed Xero but with the wrong cost mappings. Your marketing-finance tool calculates CM2 but uses a different COGS figure than your accountant.
This is where most brands lose visibility. Not because any single tool is broken, but because nobody owns the integration layer. Nobody is making sure the numbers reconcile across all three.
What to Do About It
You don't need to fire your bookkeeper. You need to stop expecting them to do a job they were never hired for.
First: restructure your chart of accounts so variable costs are separated from fixed costs. Shipping, payment processing, pick and pack, packaging, marketplace commissions — these should all sit between gross profit and your marketing line, not in overheads.
Second: make sure your COGS reflects true landed cost. If your inventory system isn't tracking freight, duties and handling at the SKU level, your margins are wrong.
Third: build or buy a management P&L that follows the CM1 → CM2 → CM3 → Net Profit structure. Update it monthly. Use it to make decisions.
Fourth: calculate the metrics that sit between accounting and marketing — CM2 per order, new customer CAC, CAC payback period. These are the numbers that tell you whether growth is actually profitable, and they feed directly into setting your ad budget from your P&L.
Your bookkeeper keeps you compliant. Management accounting keeps you informed. You need both — and right now, you're probably only paying for one.
