Reverse funnel: work out how many leads and how much spend you need to hit your target
Most marketing plans start from the wrong end: “we have R$ 20k a month, what can we do with it?”. The reverse funnel flips the question: “we want R$ 300k from new customers, what does that take?”. The answer shows up as sales, leads and budget — and quickly shows whether the target is realistic with the funnel you have today.
The logic, working backwards
Revenue target ÷ average ticket = sales needed
How many new sales it takes to reach the number.
Sales ÷ close rate = leads needed
How many leads sales needs to work to close those deals.
Leads × cost per lead = media budget
How much to invest to generate that lead volume at today’s cost.
Budget ÷ sales = acquisition cost per sale
What each sale costs in media — and whether that fits your margin.
What your target requires
Use your actual close rate from recent months, not the one you wish you had.
This only counts media. Sales salaries, tools and content production raise the total acquisition cost.
When the numbers don’t add up
The result often comes as a shock: the budget required is far higher than what’s available, or the cost per sale eats a big chunk of the ticket. Before concluding the target is impossible, test what happens when you change each variable in the calculator:
| Lever | How to improve it | Where to act |
|---|---|---|
| Close rate | Better qualification, fast response, follow-up cadence | CRM and sales process |
| Cost per lead | Targeting, creatives, a landing page that converts | Media and website |
| Average ticket | Bundles, cross-selling, repositioning the offer | Product and sales |
| Revenue from existing customers | Repeat purchases and referrals reduce dependence on new customers | Automation and relationship |
In most operations we analyze, small gains in close rate have more impact than budget increases. Going from 5% to 7% close rate cuts the leads needed for the same target by almost 30%.
Worked example: from revenue target to media plan
Picture a B2B services company that wants to bring in R$ 200k a month from new customers. The average ticket is R$ 4k, the close rate over the last six months is 4% and the cost per lead in current campaigns is R$ 70. Applying the reverse funnel:
- R$ 200,000 ÷ R$ 4,000 = 50 sales needed;
- 50 sales ÷ 4% = 1,250 leads for sales to work;
- 1,250 leads × R$ 70 = R$ 87,500 in media a month;
- R$ 87,500 ÷ 50 = R$ 1,750 in media per sale, almost 44% of the ticket.
The math shows the target is possible, but expensive. Before asking for more budget, simulate the effect of each lever:
| Scenario | Leads needed | Media budget | Media per sale |
|---|---|---|---|
| Current (4% close rate, CPL R$ 70) | 1.250 | R$ 87,500 | R$ 1,750 |
| Close rate rises to 6% | 834 | R$ 58,380 | R$ 1,168 |
| CPL drops to R$ 55 | 1.250 | R$ 68,750 | R$ 1,375 |
| Both improvements together | 834 | R$ 45,870 | R$ 917 |
The numbers are illustrative, but the pattern repeats in most operations: improving the close rate usually pays off more than cutting cost per lead, because the effect multiplies across the whole funnel volume.
How to break the funnel into stages: lead, MQL, SQL and sale
A single close rate (lead → sale) is a good start, but it hides where the funnel loses people. In operations with a structured sales process, it’s worth splitting the stages:
Lead → MQL (marketing-qualified lead)
How many leads fit the minimum profile: industry, size, role or revenue. A low rate here points to a media targeting problem or a mismatched promise in the ad.
MQL → SQL (opportunity accepted by sales)
How many qualified leads accept a conversation and confirm a need. A low rate here usually points to slow first contact or a generic approach.
SQL → sale
How many opportunities turn into contracts. This is where proposal, price, social proof and the salesperson carry weight.
Multiplying the stages gives you the final rate. For example: 30% lead to MQL, 40% MQL to SQL and 35% SQL to sale gives 4.2% lead to sale. With the funnel broken down, the reverse funnel no longer just says “we need more leads” — it points to which stage deserves attention first.
Reverse funnel by acquisition channel
Each channel has its own cost per lead and close rate. A Google Search lead usually costs more and closes more, because the person was already looking for the solution. A Meta Ads lead usually costs less and needs more nurturing. That’s why the math gets more accurate when done per channel, and only then added up.
In practice, build one row per channel with real CPL and close rate, split the target between them according to each one’s capacity and compare media cost per sale. That’s how budget stops being split by habit and starts being split by return — the same principle we use in Manáry’s paid media management.
Common mistakes when building a reverse funnel
- Using the rate you want instead of the real one. The reverse funnel only works with data from your CRM. An optimistic rate produces a budget that will never hit the target.
- Ignoring the sales cycle. If a deal takes 60 days to close, this month’s leads pay for the target two months from now. Plan with that lag.
- Forgetting seasonality. Cost per lead and close rate change through the year; use the average for the same period last year when you have history.
- Mixing new-customer revenue with recurring revenue. The reverse funnel calculates acquisition. Revenue from your current base is a separate calculation.
- Counting only media. Tools, the sales team and content production are also part of acquisition cost.
How often to revisit the numbers
Review the four numbers — ticket, close rate, cost per lead and target — monthly, and the split between channels quarterly. If any of them moves more than 20% in a month, redo the reverse funnel before deciding to raise or cut budget.
Frequently asked questions
What is a reverse funnel?
It’s a planning method that starts from the revenue target and works backwards to how many sales, opportunities and leads you need, and how much to invest in acquisition to generate them.
What conversion rate should I use if I have no history yet?
Start with a conservative estimate based on conversations with sales and validate it in the first 60 to 90 days, adjusting the math as soon as real CRM data comes in.
Does the reverse funnel work for e-commerce too?
Yes. The logic is the same, swapping leads for sessions: revenue target divided by average ticket gives the number of orders, orders divided by conversion rate give sessions, and sessions multiplied by cost per click give the budget.
What’s the difference between CAC and media cost per sale?
Media cost per sale only counts ad spend. CAC includes every acquisition cost, such as the sales team, tools and content production, so it is always higher.
Want the reverse funnel built with your real numbers?
In the diagnosis, we cross-check media, website and CRM to show which lever moves the target with the least investment.
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