Unit Economics Calculator

Most UK D2C brands are optimising to the wrong number. They religiously track ROAS, use PMax as a catch-all and watch dashboards glow green whilst your margin compresses and cash flow tightens. This free calculator maps every cost layer between a sale and a pound of real profit, so you know exactly where your money goes and what your platform targets needs to align to.

What the Calculator Covers

Full P&L Waterfall
Gross Revenue to CM1 to CM2 to CM3 to Net Profit, line by line
Breakeven ROAS Targets
Calculated at CM1, CM2 and CM3 levels, not just a blended guess
Return Rate & BNPL Impact
Model how returns and BNPL adoption erode your real net revenue
Sensitivity Chart
Visualise profit at every volume level and spot your breakeven units instantly

Who This Is For

This tool is designed for UK D2C founders, CMOs, heads of growth, and e-commerce finance leads who need to pressure-test their unit economics before scaling ad spend. It's particularly useful if you're:

  • Sense-checking whether the ROAS targets set in Google Ads or Meta actually reflect your margin structure, rather than platform defaults or last quarter's gut feel
  • Running contribution margin reviews and need a single source of truth across COGS, fulfilment, returns and marketing
  • Modelling the impact of a pricing change, discount promotion, or new fulfilment partner
  • Preparing investor materials and need a defensible unit economics model
Kiezo Growth
Build Your Unit Economics Model
Answer a few questions about your business and we'll pre-load the calculator with your real numbers. Takes 2–3 minutes. Skip anything you don't know — we'll use sensible benchmarks in its place.
Returning user? Upload your saved config to reload your numbers instantly — no need to go through the questions again.
Could not read that file. Please use a saved Kiezo config JSON.
Step 1 of 7 — Volume & Pricing
Let's start with your sales numbers.
This model works on a per-unit or per-SKU-range basis. If your business sells multiple product lines with different margin profiles, use a single representative SKU or range rather than blending across all products — blended inputs will produce a blended output that may not be actionable for any individual line.
Any field you leave blank will use a benchmark default. You'll see exactly which defaults were applied when you reach the calculator.
How many units do you sell per month?
Leave blank → benchmark default: 3,000 units/month
What is your full-price average order value?
Enter your AOV before any discounts are applied
£
Leave blank → benchmark default: £10
On average, what discount do customers get?
Across sale periods, promo codes and offers — if none, enter 0
%
Leave blank → benchmark default: 10%
Step 2 of 7 — Cost of Goods
What does it cost to make or buy the product?
What percentage of your full-price AOV is the cost to make or buy the product?
This is your COGS — e.g. if your full-price AOV is £100 and the product costs you £35, enter 35
%
Leave blank → benchmark default: 30%
Step 3 of 7 — Returns
Tell us about your returns.
What percentage of your orders are returned?
Use your last 90-day return rate if available — if unsure, the UK D2C average is around 20%
%
Leave blank → benchmark default: 20%
What does it cost you to process each returned item?
Include postage labels, re-inspection and re-packaging — not the refund itself
£
Leave blank → benchmark default: £1.00 per return
Of the units returned, what percentage can't be resold and are written off?
If most stock comes back resaleable, enter a low number. If much of it is damaged or unsellable, go higher
%
Leave blank → benchmark default: 10%
Step 4 of 7 — Shipping & Fulfilment
How much does it cost to get orders out the door?
What is your average shipping cost per unit dispatched?
Your courier cost per parcel — not what you charge the customer
£
Leave blank → benchmark default: £0.70 per unit
What do you pay per month for warehousing and fulfilment?
Enter only the portion attributable to this product or range — leave at 0 if you fulfil in-house with no direct cost
£
Leave blank → benchmark default: £250/month
Step 5 of 7 — Payments
Payment processing and BNPL fees.
What percentage does your payment gateway charge per transaction?
Stripe is typically 1.4–2.9%. Check your dashboard if unsure
%
Leave blank → benchmark default: 2%
What percentage of your customers pay via BNPL — Klarna or similar?
If you don't offer BNPL, enter 0
%
Leave blank → benchmark default: 20%
What fee does your BNPL provider charge you per transaction?
Klarna typically charges merchants 2.99–5.99%. Check your provider agreement
%
Leave blank → benchmark default: 6%
Step 6 of 7 — Marketing
What are you spending to acquire customers?
How much do you spend on paid acquisition per month, for this SKU/range?
Include the portion of agency fees, creative production, and attribution tooling attributable to this SKU or range — not your entire business spend. Platform media spend alone is acceptable, but will produce a less complete NCAC than your true all-in cost of acquisition.
£
Leave blank → benchmark default: £1,500/month
For NCAC to be accurate, your new customer count must come from your back-end data — Shopify orders, your CRM, or your order management system. Platform-reported new customer figures (Google Ads, Meta) overcount: they use cookie and device signals rather than your actual customer database, and they claim credit across channels simultaneously. Pull the number from your back end, not your ads dashboard.
How many new customers did that spend acquire?
Most brands track this monthly, but use whatever period matches your acquisition spend figure above. Pull from Shopify, your CRM, or your order management system — not your ads platform. Leave at 0 if you don't track this yet — it unlocks your NCAC figure.
Leave blank → benchmark default: 0 (NCAC not calculated)
Step 7 of 7 — Fixed Costs
One last one — fixed overhead.
What are your monthly fixed costs attributable to this product or range?
Salaries, software, rent, agency fees — only include what you'd apportion to this SKU or range. Leave at 0 to evaluate on contribution margin only
£
Leave blank → benchmark default: £2,000/month

Understanding Your Three Margin Layers

UK D2C brands operate across three distinct profit levels, each with its own breakeven thresholds. Confusing them is one of the most common and costly mistakes in performance marketing (or not knowing them at all):

  • CM1 (Gross Profit): Net revenue minus COGS. Your gross margin percentage. This is the ceiling; every other cost comes out of here.
  • CM2 (Contribution Margin): CM1 minus all variable fulfilment costs: shipping, transaction fees, BNPL fees, returns handling, write-offs and warehousing. This is the margin your marketing budget is actually competing with.
  • CM3 (Variable Profit): CM2 minus your marketing and sales spend. If CM3 is negative at your current ROAS, you are destroying margin on every order, regardless of what your agency's dashboard shows.

The breakeven ROAS calculator outputs a target at each of these three levels, giving you a clear guardrail for how hard you can push acquisition without going underwater.

Vertical calculators

Built for your specific industry

Each vertical has its own cost structure. Pick the calculator that matches your business for pre-loaded industry benchmarks.

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Deep dive

Article  ·  10 min read

What your breakeven ROAS actually is - and why the number your agency uses is almost certainly wrong

The unit economics in this calculator feed directly into your true breakeven ROAS. Most brands - and most agencies - calculate it from revenue margin alone. This article shows why that understates your real threshold, and what to use instead.

Read article
Article  ·  5 min read

Contribution margin in ecommerce, explained: CM1, CM2 and CM3

The cost lines this calculator models are the contribution margin waterfall. This article walks gross revenue down through CM1, CM2 and CM3 - and shows how to build a Google Ads account around the number your business actually keeps, not the one the dashboard shows.

Read article

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