Sales funnels and conversion rates with numbers
Map your sales funnel step by step, calculate step and overall conversion rates, and find the bottleneck that is worth fixing first.
What you will learn
- What a sales funnel is and how to define its steps precisely
- How to calculate step conversion rates, overall conversion rate, value per visitor and value per lead
- How to find the bottleneck and estimate the effect of an improvement before you build it
- Why small numbers can fool you when you compare two versions
Explanation
A sales funnel is the sequence of steps a person goes through from first contact to purchase. It is called a funnel because fewer people reach each next step. Email lists and website structure were covered in earlier lessons; here you connect them into one measurable path.
Define steps you can count
Each step must be an event you can measure, such as "visited the landing page", "entered an email address", "clicked to the sales page", "completed payment". Vague steps like "became interested" cannot be counted, so they cannot be improved.
Two common funnel types:
- Lead funnel: visitor → lead (someone who gave an email address in exchange for a free resource, called a lead magnet) → sales page visit → buyer.
- Shop funnel: session → product page view → add to cart → checkout completed.
The key formulas
- Step conversion rate = people at this step ÷ people at the previous step
- Overall conversion rate = buyers ÷ people at the first step = product of all step rates
- Revenue per visitor (RPV) = revenue ÷ visitors
- Value per lead = revenue ÷ leads
Because the overall rate is a product of steps, improving any one step by 20% raises sales by 20%. Improving three steps by 20% each raises sales by 1.2 × 1.2 × 1.2 = 1.728, so by about 73%, not 60%.
Finding the bottleneck
The bottleneck is the step where you lose the most people relative to what is realistic for that step. Compare each rate with your own history or with a sensible target, not with figures from someone else's very different business. Then ask: which fix is cheapest for the largest gain? Often it is a step near the end, such as checkout, because everyone who reaches it already wants to buy.
Value per lead is a practical number: it tells you the most you can pay to get one new email subscriber (for example through ads) before you lose money, after you also apply your margin.
Beware small samples
If version A of a page produced 6 sales and version B produced 9, that difference may be pure chance. A rule of thumb: do not declare a winner until each version has dozens of conversions and has run for at least one full week, so weekdays and weekends are both included. A/B test means showing two versions to comparable visitors at the same time.
Worked example
Hypothetical example: a freelance designer sells a €97 online course on preparing print files. Last month the funnel looked like this (VAT and payment fees excluded):
| Step | People | Step rate |
|---|---|---|
| Landing page visitors | 10,000 | – |
| Leads (downloaded free checklist) | 400 | 4% |
| Clicked from email to sales page | 120 | 30% |
| Bought the course | 12 | 10% |
- Overall conversion: 12 ÷ 10,000 = 0.12% (check: 4% × 30% × 10% = 0.12%)
- Revenue: 12 × €97 = €1,164
- Revenue per visitor: €1,164 ÷ 10,000 = €0.12 (rounded)
- Value per lead: €1,164 ÷ 400 = €2.91
Now compare two options. Option 1: double traffic to 20,000 visitors (expensive). Option 2: improve the free checklist offer so the opt-in rate rises from 4% to 8%. Both give 24 sales, but option 2 also keeps the cost of traffic the same. Improving all three steps by 20% each would give 12 × 1.728 = about 21 sales without one extra visitor.
Common mistake
Practice activity
Hypothetical online shop, one month: 5,000 sessions; 40% view a product page; 8% of product viewers add something to the cart; 50% of those with a cart complete checkout. On paper: (a) calculate orders and the overall conversion rate; (b) the team can either raise checkout completion from 50% to 60% (by adding a guest checkout) or raise add-to-cart from 8% to 9% (by new photos). Which gives more orders?
Show solution
(a) Product views: 5,000 × 40% = 2,000. Carts: 2,000 × 8% = 160. Orders: 160 × 50% = 80. Overall rate: 80 ÷ 5,000 = 1.6%.
(b) Checkout to 60%: 160 × 60% = 96 orders (+16). Add-to-cart to 9%: 2,000 × 9% × 50% = 90 orders (+10). The checkout fix gives more orders: a 10-point gain at a late step affects buyers who are already close to purchase.
Limitations: real changes rarely hit exactly the planned rate, and one month of data can vary by chance. Re-measure after the change.
Key takeaways
- Define funnel steps as countable events and measure each step rate.
- Overall conversion is the product of step rates, so improvements multiply.
- Revenue per visitor and value per lead tell you what traffic and leads are worth.
- Fix the bottleneck before buying traffic, and do not trust tests with only a few conversions.
Next step
In the next lesson you look at the price inside the funnel and compare one-time, subscription and freemium pricing models.
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