• Marketing Law

The Law of Thirds

A foundational framework for understanding conversion funnels, setting realistic budgets, and optimizing your marketing spend from impressions to closed deals.

Law of Thirds in Marketing

30%

Close Rate

From qualified leads to closed deals

30%

Qualification

Of leads become qualified prospects

30%

Conversion

Of impressions convert to leads

Defining the Law of Thirds

In many sales organizations, a simplified “law of thirds” assumes a ~30% close rate from qualified leads, ~30% of leads become qualified, and ~30% of impressions convert to leads. While this last figure is aggressive for many channels, the model produces a clean, illustrative funnel — not a universal benchmark, but a powerful framework for planning.

Defining the Law of Thirds

The key to applying the Law of Thirds effectively is working backward from your desired closed deals. This reverse-engineering approach gives you a clear picture of exactly how many leads and impressions you need.

Deals → Leads

If you close 30% of leads, you can calculate exactly how many leads you need to hit your deal target.

Formula
Leads Required = Deals Closed ÷ 0.30
Formula
Goal
30 Closed Deals
Conversion Rate
30%
Leads Required
30 ÷ 0.30 = 100 Leads

Leads → Impressions

Now apply the impression-to-lead conversion rate to determine how many impressions your campaign needs to generate.

General Formula
Impressions required = Leads ÷ Impression→Lead Rate
Pure "Law of Thirds" (30%)
100 ÷ 0.30 = 333 impressions

This is mathematically correct but unrealistic for most paid or organic channels — unless impressions are already highly targeted (e.g., retargeting or warm audiences).

More Realistic Conversion Benchmarks

Most real-world funnels look quite different from the idealized “thirds” model. Here are the typical conversion rates you can expect across different funnel stages:

Stage
Typical Rate

Impression → Click
0.5% – 3%
Click → Lead
10% – 30%
Lead → Close
20% – 35%

Conservative but Realistic Rates

Using Lead → Close = 30%, Click → Lead = 20%, and Impression → Click = 2%, here is the step-by-step calculation:

STEP-BY-STEP CALCULATION
1. Deals needed: 30
2. Leads needed: 30 ÷ 0.30 = 100
3. Clicks needed: 100 ÷ 0.20 = 500
4. Impressions needed: 500 ÷ 0.02 = 25,000

Final Funnel Summary

To close 30 deals at a 30% close rate, you typically need approximately:

Realistic Scenario Funnel
Working backward from 30 closed deals

1
Impressions Required
25,000
500 ÷ 0.02 = 25,000
2
Clicks Needed
500
100 ÷ 0.20 = 500
3
Leads Required
100
30 ÷ 0.30 = 100
4
Deals Closed
30
Target achieved ✓

Key Insight

The critical multiplier in your model is impression → lead efficiency. Small improvements early in the funnel dramatically reduce required spend and volume.

–33%
IMPRESSIONS REDUCED
By improving impression → click from 2% to 3%

–25%
LEADS REDUCED
By improving lead → close from 30% to 40%

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