Divide conversions by visitors and multiply by 100, and you have your conversion rate. The calculator below does that for one page, or for two versions side by side, and tells you how far a single conversion moves the number.
Add a second variant and you get the difference in points and in relative terms, plus a plain warning when the numbers are too small to trust.
Conversion rate calculator
Using the calculator
- Pick one goal and one date range. A conversion is whatever you decided counts: a sale, a sign-up, a booked call.
- Type in visitors (or sessions) and conversions for that page or funnel.
- Running an A/B test? Put version A in the first pair and version B in the second. Both should cover the same dates.
- Press the button. Read the rate, the difference and any warning underneath.
Small numbers move a lot
This is the part most people skip. Every conversion rate has a hidden figure behind it: how much one conversion is worth in points. On 1,500 visitors, one extra sale moves the rate by 0.07 points. On 150 visitors, it moves it by 0.67 points. On 30 visitors, a single sale is 3.33 points.
That's why a test on a small page can show one version miles ahead after a few days and then flip the following week. Nothing changed except chance. The calculator flags any side with under 100 conversions. That line is a cautious rule of thumb we've chosen, not a statistical test, and passing it doesn't prove a winner. It's simply the point where a couple of lucky or unlucky days stop dominating the result.
If your traffic is too low to test, don't stop improving. Make the changes that are clearly sensible, such as a clearer headline, a shorter form or a faster page, and watch the rate over a longer stretch. There are plenty of ideas in how to improve your conversion rate.
Worked example: an A/B test
Version A of a landing page had 1,500 visitors and 45 sign-ups. 45 / 1,500 = 0.03, so the conversion rate is 3.00%.
Version B also had 1,500 visitors, with 60 sign-ups. 60 / 1,500 = 0.04, so 4.00%.
The difference is 4.00 - 3.00 = +1.00 point. In relative terms, 4 / 3 = 1.333, so B converts 33.3% better than A. One conversion on 1,500 visitors is worth 100 / 1,500 = 0.07 points.
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It looks like a clear win, and it might be. But both sides are under 100 conversions, so the calculator shows the small numbers warning. Fifteen extra sign-ups is a real gap; it's also the kind of gap that can shrink when the test runs another fortnight. Keep it going.
Conversion rate FAQs
How do you calculate conversion rate?
Divide the number of conversions by the number of visitors or sessions, then multiply by 100. 45 conversions from 1,500 visitors is a 3.00% conversion rate.
Should I use visitors or sessions?
Either works, as long as you use the same one every time. Sessions count visits, so one person coming back three times is three sessions. Visitors count people. Rates by session usually come out lower.
What is a micro-conversion?
A small step on the way to the main goal, such as adding to basket, starting a form or watching a demo video. Tracking them shows where people drop out before the final conversion.
How many conversions do I need before trusting an A/B test?
There's no single number, because it depends on how big the difference is. The calculator warns you when either side has under 100 conversions, since small numbers move a lot, but that warning is not a significance test.
What is the difference between points and relative change?
Points are the simple gap between two rates, so 3% to 4% is 1 point. Relative change compares them, so 3% to 4% is a 33.3% improvement.
Does the calculator save my numbers?
No. Everything runs in your browser and nothing is stored or sent anywhere.
Can conversions be higher than visitors?
Only if one person can convert more than once, such as buying twice. If that happens, count orders against sessions, or count converting visitors against visitors.
More on conversion
- How to improve your conversion rate
- Ways to boost your site's conversion rate
- Conversion rate optimisation for ecommerce
- What is ROAS, for paid traffic
- Click-through rate calculator, for the step before the visit
Decide what to count before you count it
A conversion rate is only as good as the two numbers that go into it, and both are choices.
The conversion. Your main conversion is the action that matters to the business: a purchase, a paid sign-up, an enquiry. Micro-conversions are the steps on the way, like adding to basket, starting checkout or clicking to a pricing page. Measure both, but don't mix them in one rate. A page that converts 12% of visitors to add-to-basket and 2% to purchase is telling you two different things, and the gap between them is where your best fixes usually sit.
The visitors. Sessions count visits; users or visitors count people. If someone reads your page on Monday and buys on Thursday, that's two sessions, one person and one conversion. Session-based rates come out lower and are easier to get from most analytics tools. Visitor-based rates are closer to how people buy. Pick one, write it down and use it every time, or your month-on-month comparisons won't mean anything. In an online shop the same choice applies to orders, which is covered in conversion rate optimisation for ecommerce.
