Your Revenue Is Real.
Your COGS
Should Be Too.
E-commerce accounting is not like regular business accounting. Inventory, platform fees, sales tax nexus, and multi-channel reconciliation require specialized systems — and most bookkeepers don't have them.
What's Actually
Costing You Money
E-commerce accounting problems don't show up as obvious errors — they show up as margin compression, cash crunches, and tax surprises.
COGS is the most important number in your business — and the hardest to track. When inventory moves across warehouses, platforms, and fulfillment centers, most sellers have no idea what their actual cost of goods sold is.
Amazon, Shopify, and Etsy all net out fees, refunds, chargebacks, and advertising costs before depositing. Reconciling these payouts to actual revenue is a full-time job without the right systems.
Economic nexus rules mean you may owe sales tax in states where you've never set foot. With 45 states collecting sales tax and different thresholds, this is one of the fastest-growing compliance risks for e-commerce sellers.
You're growing fast and revenue looks great — but cash is always tight. The culprit is usually inventory purchases, platform payout timing, and advertising spend that outpaces collections.
If you're not tracking landed cost (product + shipping + duties + prep fees), your COGS is wrong. That means your gross margin is wrong, your pricing decisions are wrong, and your taxes may be wrong.
Selling on Amazon, Shopify, and Etsy simultaneously means three different reporting systems, three different payout schedules, and three different fee structures — all needing to be consolidated into one P&L.
High return rates (common in apparel, electronics, and home goods) create complex accounting entries that most bookkeepers handle incorrectly — overstating revenue and understating COGS.
Amazon PPC, Meta ads, and Google Shopping spend needs to be tracked against revenue by campaign and product. Without this, you can't tell if your advertising is profitable.
What Are You Trying to Solve?
E-commerce sellers come to us at very different stages. We work with all of them.
Get the Books Right
Your current books are a mess of bank feeds and guessed COGS. You need clean, accurate financials before you can make any real decisions. We start here.
Understand Your Margins
You're selling a lot but profit is elusive. We build the product-level margin analysis that shows you exactly which SKUs are making money and which ones are eating it.
Scale Without Breaking
You're growing fast and the financial systems that worked at $500K won't work at $5M. We build the infrastructure — inventory systems, cash flow forecasting, tax strategy — that scales with you.
What a Profitable E-Commerce
Operation Looks Like
Most sellers are flying blind on margin. They know their revenue. They don't know their profit. Here's what it looks like when the financial infrastructure is built correctly.
“We thought we were profitable. Turns out we were subsidizing our worst SKUs with our best ones. Once we could see it, we cut the losers and margins jumped 12 points.”
— E-Commerce Client, 3-Platform Seller
COGS Accurate to the SKU
Every product has a true landed cost: purchase price, freight, duties, FBA fees, returns. Margin is calculated at the SKU level, not the store level.
Inventory Reconciled Monthly
Your books match your warehouse. Shrinkage, returns, and write-offs are tracked. You're not discovering a $40K inventory discrepancy at year-end.
Sales Tax Exposure Mapped
You know which states you have nexus in, what you owe, and you're filing on time. No surprise assessments. No back-tax liability building in the background.
Cash Flow Forecasted 90 Days Out
You know when the next inventory buy hits, when the Amazon payout lands, and what your cash position will be. No more guessing before a reorder.
Services for E-Commerce Sellers
We work in three stages: get the foundation right, then build visibility, then optimize for growth.
Need a one-time project? Our Advisory Services menu includes à la carte projects like COGS cleanup, sales tax nexus analysis, and inventory system setup — priced transparently.
The foundation. Clean books, correct COGS methodology, and inventory reconciliation so your numbers actually mean something.
The rhythm. Monthly close, margin reporting by SKU/channel, and sales tax monitoring so nothing builds up in the background.
The strategy layer. Cash flow forecasting, inventory financing, and tax planning for sellers ready to scale.
What Changes When We Work Together
Economic Nexus Is the Biggest Hidden Risk for E-Commerce Sellers
Since the 2018 South Dakota v. WayfairSupreme Court decision, states can require you to collect and remit sales tax based on economic activity alone — even if you've never set foot there. Most states have thresholds of $100K in sales or 200 transactions.
If you're selling across state lines and haven't done a nexus analysis, you may have exposure you don't know about. We help you understand your risk, get compliant, and set up automated filing going forward.
Integrations & Software
We work with the tools you already use — or help you choose the right ones.
What We've Done for E-Commerce Brands
Real outcomes from real e-commerce businesses — not projections.
Shopify Brand — $3.2M, Montana
Rebuilt inventory costing from scratch after discovering 18 months of incorrect COGS calculations. Restated financials, corrected tax returns, and implemented real-time inventory tracking.
Amazon FBA Seller — $1.8M
Corrected multi-state nexus filings, restructured to S-corp, and implemented quarterly estimated tax planning. Net savings of $19K in year one plus eliminated $4K in penalty exposure.
DTC Brand — $5.4M, Colorado
Built lender-ready financials with clean inventory valuation and a 3-year cash flow model. Secured a $2.1M revolving credit line to fund peak season inventory purchases.
What E-Commerce Brands Say
“Our COGS were wrong for 18 months and we didn't know it. 406 found it, fixed it, and restated our financials. We were overpaying taxes and underpricing products. Both problems solved.”
“Amazon FBA accounting is a nightmare — reimbursements, FBA fees, inventory adjustments. 406 was the first accountant who actually understood it. Clean books, correct taxes, no drama.”
Frequently Asked Questions
Ready to Know What You're Actually Making?
Whether you're a solo Etsy seller or a multi-channel brand doing $5M, we build the financial systems that turn your sales data into real business intelligence.
Serving e-commerce sellers across Montana and the Mountain West — and nationwide for remote engagements.
Tools & Systems
Automate Your Back Office
We connect your Shopify, Amazon, or WooCommerce store to your accounting, CRM, and fulfillment workflows — eliminating manual reconciliation and giving you real-time margin visibility by SKU and channel.