Conversion Rate Calculator

Conversion rate formula

Conversion rate compares completed actions with the opportunities to complete them. A completed action might be a purchase, a signup or a quote request. The denominator might be visitors, sessions or ad clicks, depending on the report.

Conversion rate = conversions / traffic x 100

If 250 out of 10,000 visitors convert, the rate is 2.5%: 250 / 10,000 x 100. That is one converted visitor for every 40 visitors, or 25 per 1,000. Keep the action, date range and traffic source consistent.

For a general part-and-whole calculation, use the percentage of total calculator. Clicks divided by impressions are a different measure, covered by the CTR calculator.

Visitors, sessions and conversion events

Choose a counting basis that matches the numerator and denominator in your report. Counting people, visits and repeated events can produce different answers even for the same website.

For example, one visitor makes two visits and buys during the second visit. The converted-visitor rate is 1 / 1 = 100%; the converted-session rate is 1 / 2 = 50%. Counting three purchase events would answer another question again.

Google Analytics defines its session key event rate using sessions in which a key event occurred, and its user key event rate using users who triggered one. Dividing the total number of events by sessions does not reproduce the session key event rate. See the Google Analytics metric definitions.

A visitor or session can be counted as converted only once in these share-based modes, so the numerator cannot exceed the denominator. Event-based rates may exceed 100% when several credited conversions belong to one opportunity. Google Ads also distinguishes counting every conversion from counting one. An events-per-click rate is not the probability that a person converts.

How much traffic do you need?

To plan traffic for a conversion target, divide the target count by the assumed rate as a decimal.

Traffic needed = target conversions / (conversion rate / 100)

For 100 conversions at an assumed 2.5%, the calculation is 100 / 0.025 = 4,000 visitors. For 50 conversions at 3%, the exact figure is 1,666.67, so the calculator rounds up to 1,667 whole visitors.

This is a planning estimate at a constant assumed rate. Real traffic quality, offer, tracking and customer behavior can change, so reaching the traffic count does not guarantee the target. A positive target cannot be reached at an assumed rate of zero.

Conversions needed for a target rate

Multiply the traffic count by your target rate as a decimal. With 1,250 visitors and a target of 3%, you need 37.5 converted visitors mathematically. Since people are whole counts, the calculator rounds up to 38, giving an achieved rate of 3.04%.

Conversions needed = traffic x target rate / 100

Visitor and session modes round up to a whole converted person or session. Event modes keep the calculated amount because attribution reports can credit fractional conversions. Raw event counts themselves are whole numbers.

Compare conversion rates correctly

Campaign A converts 20 of 1,000 visitors: 2%. Campaign B converts 60 of 2,000: 3%. B is 1 percentage point higher, and its relative increase is 50%: (3 – 2) / 2 x 100.

Those are two ways of describing the same difference. The percentage points calculator explains the distinction further. If the original rate is zero, a relative percentage increase is undefined.

Use the same counting basis and comparable periods for both campaigns. A difference in observed rates does not establish that a change caused it, or that it is statistically significant. This tool compares the arithmetic; it does not run an A/B significance test.

Combine campaigns using totals

Adding rates and dividing by the number of campaigns gives every campaign the same weight. To find the combined rate, add the conversions, add the traffic, and divide the totals.

Combined rate = sum of conversions / sum of traffic x 100

A small campaign converts 5 of 10 visitors, or 50%. A larger campaign converts 90 of 100, or 90%. Their combined rate is 95 / 110 x 100 = 86.363636%. The simple average of their rates is 70%, which does not describe the combined visitors.

Combine only non-overlapping counts that use the same action, period and counting rules. Adding campaign visitors can double-count people who appear in several campaigns. For other weighted-rate questions, use the average percentage calculator.

Conversion rate in Excel or Google Sheets

With converted visitors in A2 and total visitors in B2, use the following formula and format the cell as a percentage:

=A2/B2

For a traffic target, put target conversions in A2 and the assumed rate in B2 as a percentage such as 2.5%. Round up the required traffic to a whole count:

=ROUNDUP(A2/B2,0)

Both formulas need a nonzero denominator. Do not multiply the first formula by 100 as well when applying percentage formatting.

Common questions

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