Ecommerce Financial Model: What to Include

Start with the decision the model has to support

A model is useful when it answers a specific question: can we afford this purchase order, what happens if ad costs rise, how much runway do we have, what will an investor test. Write the two or three questions first. They decide how much detail you need.

1. Revenue built from drivers

Do not type monthly revenue as a number. Build it from inputs you can check against your store data:

• Traffic or ad spend by channel and the cost per visit or per acquisition
• Conversion rate and average order value
• New versus repeat customers, with a repeat-purchase curve by cohort
• Marketplace sales modelled separately if they have different fees and payout rules Keep one row per channel. When a channel changes, you change one line, not the whole model. For a deeper build on this layer, see our bottom-up DTC revenue forecast and how to forecast revenue with no history.

2. Margin in layers, not one gross margin number

Take each sale down in steps so you can see where profit leaks: product cost and landed cost (freight, duties), payment and marketplace fees, shipping and fulfilment, returns and refunds, and then paid acquisition. What is left is contribution margin. Do it at SKU or category level where products differ widely; the SKU profitability guide shows a worked example.

3. Inventory and the cash conversion cycle

This is the layer most templates skip. Model purchase orders by SKU: order date, deposit and balance dates, lead time, landing date and sell-through. Inventory is cash you have already spent, so growth consumes cash before it creates it. Link the result to your supplier terms and payout lags.

4. Operating costs, hiring and capex

Add payroll by role with start dates, software, rent, professional fees and one-off spend. Mark which costs are fixed and which scale with revenue.

5. The three statements, tied together

A usable model produces a profit and loss, a balance sheet and a cash flow statement that reconcile. If the balance sheet does not balance, the model is not ready to show anyone. Investors will test this first; our guide on what makes a financial model credible to investors lists the checks.

6. A 13-week cash view on top

Annual and monthly models hide short-term gaps. A rolling weekly view shows the week cash drops below your buffer. See ecommerce cash flow: how to forecast and manage it.

7. Scenarios

Run at least three: base, downside (lower conversion or higher ad cost) and upside (faster growth that needs more inventory). The useful output is not the forecast, it is the trigger points: at what ad cost or return rate do we need to change plan.

Quick checklist

• Revenue comes from drivers and channels, not typed totals
• Margin is split into layers down to contribution margin
• Purchase orders and supplier terms feed cash
• Balance sheet balances and cash reconciles
• 13-week cash view and three scenarios exist
• Every assumption has a source and an owner

Template or done-for-you?

If you want a starting structure, use our financial model template or the free version. If the model has to survive investor due diligence or you do not have the time to maintain it, see our financial modelling service. A model is also different from a plan: see financial model vs business plan.