How to Calculate Conversion Rate (With Worked Examples)

This guide explains each decision with worked examples, so your conversion rates are comparable and useful for decisions.

The basic formula

Conversion rate (%) = Conversions ÷ Base × 100

• Conversions: the number of completed target actions, such as purchases, enquiries, sign-ups or booked calls.
• Base: the number of opportunities to convert, usually sessions, users or ad clicks.

Both numbers must come from the same period and the same scope (for example the same page, campaign or channel).

Step 1: Define what a conversion is

A conversion is any action you want visitors to take. It helps to distinguish two levels.

Type	Examples	Use
Macro conversion	Purchase, quote request, booked call, signed contract	Main business result
Micro conversion	Newsletter sign-up, download, click on phone number, adding to cart, watching a video	Steps towards a macro conversion

Calculate conversion rates for macro conversions as your main KPI. Micro conversions help you understand where visitors drop off, especially when macro conversions are few.

Be precise. "Enquiry" should mean the same thing every month, for example "submitted contact form excluding spam", not sometimes form submissions and sometimes phone calls.

Step 2: Choose the right base

The base you divide by changes the result. Three common options:

Base	Question it answers	Typical use
Sessions	How often does a visit lead to a conversion?	Website and landing page performance
Users	What share of people eventually convert?	Products bought after several visits
Clicks	What share of ad clicks convert?	Paid campaigns, compared with ad platform data

Worked example (hypothetical): An online shop has in one month:

• 4,000 sessions
• 2,500 users (some visited more than once)
• 80 orders

Conversion rate based on sessions: 80 ÷ 4,000 × 100 = 2.0 % Conversion rate based on users: 80 ÷ 2,500 × 100 = 3.2 %

Both numbers are correct; they answer different questions. Problems only arise when one month uses sessions and the next uses users, or when you compare your session-based rate with someone else's user-based rate.

Step 3: Calculate per page, channel or campaign

A site-wide conversion rate mixes very different traffic: people looking for your address, job applicants, existing customers logging in, new prospects. It is more useful to calculate conversion rates for specific segments:

• Per landing page: conversions from visits that started on that page.
• Per channel: organic search, paid search, email, social.
• Per campaign: using consistent UTM parameters on all campaign links.

Example (hypothetical): A service company looks at one month of data.

Channel	Sessions	Enquiries	Conversion rate
Paid search	900	27	3.0 %
Organic search	1,500	21	1.4 %
Email	200	8	4.0 %
Social	400	2	0.5 %
Total	3,000	58	1.9 %

The total of 1.9 % hides large differences. The low social rate may be fine if social is meant for awareness, or it may show that posts link to the wrong page.

Step 4: Check whether you have enough data

Conversion rates based on small numbers fluctuate a lot. If a landing page had 50 visitors and 2 conversions (4 %), one more or one fewer conversion changes the rate to 6 % or 2 %. That is random variation, not necessarily a real change.

Practical rules:

• Look at absolute numbers alongside the percentage. "2 % (12 of 600)" is more honest than "2 %".
• Use longer periods for small sites. Monthly or quarterly instead of weekly.
• Be careful with A/B tests on low traffic. Differences between variants need much more data than most small sites have in a few weeks. Use a statistical significance calculator if you run tests, and decide your sample size in advance.
• Watch the trend over several periods before drawing conclusions.

Step 5: Connect conversion rate to money

A higher conversion rate is only valuable if the conversions are worth something. Combine it with cost and revenue figures:

• Cost per conversion = cost of the channel ÷ conversions
• Revenue per session = revenue ÷ sessions
• Lead-to-customer rate = customers ÷ leads × 100

Example (hypothetical): Paid search costs €1,800 per month and brings 27 enquiries, of which 6 become customers.

• Cost per enquiry: €1,800 ÷ 27 = €66.67
• Lead-to-customer rate: 6 ÷ 27 × 100 = 22 %
• Cost per customer: €1,800 ÷ 6 = €300

To see ROAS, ROI and customer acquisition cost for such figures in one place, use the marketing ROI, ROAS and CAC calculator. For the full cost view, see how to calculate customer acquisition cost.

Why different tools show different conversion rates

You may see one conversion rate in your ad platform, another in your analytics tool and a third in your CRM. Common reasons:

• Different counting: some tools count every conversion, others one per session or user.
• Different attribution: ad platforms often credit themselves for conversions that analytics attributes to another channel.
• Consent and blocking: visitors who decline tracking or use blockers may be missing from some tools.
• Time zones and reporting delays.

Choose one reference source per metric and stick with it. For actual customers and revenue, your CRM, shop or accounting system is usually the most reliable.

Improving conversion rate: where to look first

Once you measure reliably, these are the typical levers:

1. Message match: does the landing page fulfil the promise of the ad or link?
2. Offer clarity: is it obvious what the visitor gets and what it costs?
3. Friction: long forms, slow pages, unclear buttons.
4. Trust: real references, transparent prices, visible contact details.
5. Traffic quality: sometimes the page is fine and the targeting is wrong.

Our landing page checklist turns these levers into 40 concrete checks.

Common mistakes

Mixing bases. Sessions one month, users the next.

Counting spam as conversions. Filter test and spam submissions.

Only looking at the site-wide rate. Segment by page, channel and campaign.

Celebrating small-sample changes. Check absolute numbers and longer periods.

Ignoring conversion value. A channel with a lower rate but more valuable customers can be the better one.

Summary

To calculate conversion rate, divide conversions by sessions, users or clicks from the same period and multiply by 100. Define conversions precisely, choose one base and use it consistently, segment by page, channel and campaign, and always look at absolute numbers so small samples do not mislead you. Then connect the rate to cost and revenue, because the goal is not a higher percentage but more profitable customers. Conversion rate is one of the core marketing KPIs for small business; measure it the same way every month and it becomes a reliable guide for improvement.