Product costs shouldn't live in spreadsheets forever because the process becomes harder to control as an ecommerce business adds products, marketplaces, fulfilment charges and transaction volume. A spreadsheet can work as an early-stage costing tool, but it becomes less useful when finance teams have to manually combine product costs with marketplace fees, refunds and fulfilment expenses to understand actual profitability.

‍

Why Product Costs Shouldn't Live in Spreadsheets Forever

Product costs shouldn't live in spreadsheets forever because the process becomes harder to control as an ecommerce business adds products, marketplaces, fulfilment charges and transaction volume. A spreadsheet can work as an early-stage costing tool, but it becomes less useful when finance teams have to manually combine product costs with marketplace fees, refunds and fulfilment expenses to understand actual profitability.

The problem is not spreadsheets themselves.

It is asking one spreadsheet to remain the financial control centre after the business has outgrown the process it was built for. Modern e-commerce enterprises require robust financial frameworks, eliminating reliance on fragmented logs and error-prone manual entry.

Spreadsheets work until the business changes faster than the model

Many ecommerce businesses begin with a perfectly reasonable costing process.

• There are a limited number of SKUs.
• Supplier costs are entered into a sheet.
• Someone adds shipping or fulfilment costs.
• Margin is calculated.
• Management has enough information to make decisions.

Then the business grows. A second marketplace is added, product ranges expand, supplier prices change, fulfilment costs move, and refunds increase. The finance team starts downloading additional reports. Soon, the costing spreadsheet is no longer one simple source of information. It is the place where several separate financial systems are being manually brought together.

That is when the risk changes. The spreadsheet is no longer helping calculate product costs. It is compensating for a fragmented accounting process. Without a proper cost management strategy, scaling operations becomes an administrative burden rather than a commercial opportunity.

The first problem is stale cost data

Product costing only works when the inputs are current. A margin calculation based on an outdated supplier cost may look precise while being commercially wrong. The same applies when additional costs change but are not reflected in the model.

Fulfilment costs, for example, can include storage, order processing, picking, packing, shipping and returns-related costs. These expenses directly influence ecommerce profitability and can affect pricing and product decisions.

If the product-cost spreadsheet is updated only periodically while those costs continue changing elsewhere, the calculated margin becomes less reliable. This creates a dangerous situation because the number still looks authoritative:

• It has a formula.
• It has a percentage.
• It may simply be based on yesterday's economics.

Relying on outdated metrics during a volatile supply chain climate invites severe operational missteps. Real-time visibility into manufacturing costs and inventory valuation is critical for maintaining healthy margins.

The second problem is separating product cost from selling cost

Ecommerce profitability is not explained by product purchase cost alone. A product may have an attractive difference between its selling price and supplier cost while becoming much less profitable once the wider cost of selling it is considered.

Those costs can include:

• Marketplace commissions
• Payment fees
• Fulfilment costs
• Refunds
• Other platform deductions

This is where spreadsheet-based costing often becomes complicated. The product cost sits in one file. Amazon fees appear in another report. Shopify payments appear elsewhere. Fulfilment costs need another calculation. Refunds may be contained within marketplace settlement data.

Management then relies on someone manually combining these sources to decide whether a product is profitable. That is not simply a spreadsheet issue. It is a financial-data structure issue. Implementing automated data flows prevents costly Excel errors that frequently distort quarterly financial forecasts.

The third problem is hidden assumptions

Every growing costing spreadsheet develops assumptions. One person knows which supplier price should be used. Another understands why a fulfilment percentage is applied. Someone else knows that a particular SKU needs a manual adjustment.

Those decisions may make sense. The problem begins when they exist only in the spreadsheet or in the head of the person maintaining it. As the team grows, the model becomes harder to review. Questions appear:

• Why is this cost different?
• When was this figure last updated?
• Does this formula include refunds?
• Are marketplace fees included?
• Which version is correct?

A costing process should become easier to audit as the business grows, not more dependent on institutional memory. Mitigating spreadsheet risks requires establishing transparent, repeatable workflows that do not rely on isolated local files.

The fourth problem is spreadsheet reconciliation

Manual spreadsheets can create a second version of the financial truth. Xero or QuickBooks contains the accounts. Marketplace reports contain ecommerce activity. The costing spreadsheet contains the margin model. If the three do not agree, finance has to decide which one is correct.

This can lead to repeated month-end work. Teams download new reports, paste figures into spreadsheets, fix formulas and compare totals back to accounting software. As transaction volume grows, that workflow becomes increasingly difficult to maintain.

Link My Books identifies the underlying ecommerce problem clearly: marketplaces create large volumes of operational financial data, while accounting systems need that information structured before it becomes useful for bookkeeping and reporting. The better solution is to improve the accounting data flowing into the process rather than repeatedly repairing it in spreadsheets.

Product costing needs reliable ecommerce accounting underneath it

Moving away from spreadsheet dependency does not mean every costing calculation has to live inside the accounting platform. It means the spreadsheet should not be responsible for reconstructing ecommerce financial activity that should already be clear elsewhere.

Your accounting records should give finance teams reliable visibility over:

• Gross marketplace sales
• Platform fees
• Refunds
• Taxes
• Settlement activity
• Relevant fulfilment charges

Product costing can then use those numbers as trusted financial inputs. This is very different from starting with a bank payout and using formulas to estimate what happened before the money arrived. Embracing true automation ensures that baseline figures match up across systems without manual intervention.

Where Link My Books changes the workflow

Link My Books improves the accounting layer that product-margin analysis depends on. It connects supported ecommerce platforms with Xero or QuickBooks and turns sales, fees, taxes, refunds and payout activity into structured accounting summaries.

This matters because spreadsheets are often used to fill the gaps left by poor ecommerce accounting data. If marketplace fees are unclear, they get calculated manually. If refunds are buried inside payouts, someone extracts them. If gross sales and net bank receipts do not agree, another reconciliation tab gets created.

Link My Books reduces that reconstruction work. Instead of forcing finance teams to build marketplace accounting from multiple exports, it gives them cleaner financial categories inside their accounting workflow. That gives product-cost analysis a stronger starting point.

Link My Books is not positioned as a replacement for every product-cost or inventory system. Its role is to make the ecommerce financial side accurate and structured, so finance teams can spend less time rebuilding marketplace data and more time analysing what costs actually mean for margin.

When is a spreadsheet still useful?

Spreadsheets are not automatically a bad choice. They remain useful for:

• Scenario modelling
• Supplier-price comparisons
• New product analysis
• Pricing tests
• Short-term sensitivity analysis

The problem is using them as the permanent bookkeeping bridge between ecommerce platforms and the accounting system. A model is useful when finance can change assumptions deliberately. It is less useful when half the workbook exists simply to reconstruct sales, fees and refunds that should already be structured in the accounts.

Use spreadsheets to analyse. Do not make them do all the accounting first.

How ecommerce accounting tools approach the problem

Different platforms address ecommerce financial automation in different ways, each bringing a distinct approach to the market.

A2X is established in settlement-based ecommerce accounting and converts marketplace activity into accounting summaries before sending it to accounting software.

Taxomate focuses on marketplace bookkeeping automation, particularly for sellers that want marketplace financial data summarised for accounting.

Entriwise provides marketplace-to-accounting integrations designed to reduce manual processing of ecommerce financial activity.

Link My Books is particularly strong when the objective is accountant-friendly summary accounting combined with clear visibility over marketplace sales, fees, refunds, taxes and settlements.

For product costing, that matters because reliable margin analysis starts with reliable financial inputs. The less time finance spends reconstructing platform activity manually, the more useful product-cost reporting becomes.

A better costing workflow as the business grows

The goal should be to separate accounting preparation from commercial analysis. Let ecommerce accounting automation structure marketplace activity. Keep Xero or QuickBooks as the financial record. Then use your costing process to answer commercial questions:

• Which products retain the best margin?
• Where are fulfilment costs putting pressure on profitability?
• Are marketplace fees changing the economics of a SKU?
• Do prices still reflect current costs?

That is a much stronger role for a spreadsheet than using it to reconcile several marketplaces before any analysis can begin. Integrating systems via an advanced ERP integration or dedicated connector takes the friction out of month-end reporting.

FAQ

Why shouldn't product costs live in spreadsheets forever?

Spreadsheets can work well when an ecommerce business has a small number of products and relatively simple financial activity. The problem appears as product ranges, marketplaces and costs grow. Supplier prices can become outdated, formulas can change, and marketplace fees, fulfilment charges and refunds may need to be imported manually from other systems. This makes margin reporting increasingly dependent on spreadsheet maintenance. A stronger process keeps the accounting inputs structured and reliable, then uses spreadsheets where they are most useful: analysis, forecasting and scenario modelling.

What costs should ecommerce businesses include when reviewing product profitability?

Product profitability should consider more than the purchase price of the item. Relevant costs may include marketplace fees, payment-related charges, fulfilment expenses and refunds, depending on the business model and the level of analysis required. Fulfilment itself can include storage, picking, packing, order processing and shipping. The important point is to avoid comparing detailed product revenue with incomplete costs. Finance teams need reliable accounting data before they can decide which costs should be attributed to individual products or channels.

Does Link My Books manage product costs?

Link My Books focuses on ecommerce bookkeeping automation rather than replacing every product-cost or inventory system. It structures supported ecommerce financial activity such as sales, fees, taxes, refunds and payouts before posting accounting summaries into Xero or QuickBooks. This creates cleaner financial inputs for accountants and finance teams. Product-cost calculations may still require additional business-specific data, such as supplier costs. Link My Books strengthens that process by reducing the amount of marketplace financial activity that needs to be reconstructed manually in spreadsheets.

Why are marketplace fees important when calculating product margin?

Marketplace fees reduce the amount retained from a sale and therefore influence profitability. If product-margin calculations include the selling price and supplier cost but leave marketplace deductions elsewhere in the accounts, the apparent margin can be overstated. The same issue applies to fulfilment costs and refunds. Businesses need enough financial structure to understand which costs are affecting the economics of their products. Link My Books helps make marketplace fees and other settlement components clearer inside the accounting workflow, giving finance teams better data for profitability analysis.

Can a spreadsheet still be part of a good ecommerce finance stack?

Yes. Spreadsheets remain useful for modelling, forecasts, pricing scenarios and other analysis that requires flexible assumptions. The issue is not using spreadsheets. It is using them to compensate for unstructured ecommerce bookkeeping. If finance teams repeatedly download marketplace reports, rebuild settlements and manually extract fees before they can calculate margin, the spreadsheet has become part of the bookkeeping infrastructure. Automating that underlying ecommerce accounting gives the spreadsheet a more useful role as an analytical tool rather than a permanent reconciliation engine.

Product costing should help you understand margin. It should not require you to reconstruct your ecommerce accounts first.

As the business grows, supplier costs, fulfilment charges, marketplace fees and refunds become too important to leave scattered across files and manual monthly processes. Accessing clean, real-time data allows finance teams to evaluate inventory health accurately.

Link My Books helps create a cleaner accounting foundation by structuring supported ecommerce sales, fees, refunds, taxes and payouts inside Xero or QuickBooks. That leaves finance teams with better data for the work spreadsheets are actually good at: analysing costs, testing pricing and understanding profitability.

Book a personalised demo.

‍