A/B sample duration

The calculator uses the numbers you enter. With 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power the result is 1.0 d | n~7,299. This is not an evanmiller.org sample-size tool.

This is not an evanmiller.org sample-size tool. Incrementality is on Incrementality.

Input data

Parametry modelu
Scenariusz dodatkowy

Results

Enter data and click Calculate.

How it works

A/B sample duration in this calculator is days to n from conversion, MDE and Z. With 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power the result is 1.0 d | n~7,299.

n per variant comes from conversion, MDE and Z. days = n / sessions. A proxy, not a power test. The formula uses MDE and sessions.

1.0 d | n~7,299 is not an evanmiller.org sample-size tool. Another set of numbers gives 1.4 d | n~5,634, and a further set gives 0.4 d | n~5,027. Empty scenario fields do not change the result.

Incrementality answers a different question. Attribution window does too. Here 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power leave 1.0 d | n~7,299.

Type 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power and click Calculate. Two more ready sets sit under the form: 1.4 d | n~5,634 and 0.4 d | n~5,027.

Other numbers on the same labels move the result. The first example gives 1.0 d | n~7,299.

Formula

n per variant comes from conversion, MDE and Z. days = n / sessions. A proxy, not a power test.

How to use

  1. Type 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power.
  2. Leave the scenario fields empty if you do not have those numbers.
  3. Click Calculate. This set shows 1.0 d | n~7,299.
  4. The second example under the result is 1.4 d | n~5,634, the third 0.4 d | n~5,027.
  5. This is not an evanmiller.org sample-size tool.

A/B sample duration = 1.0 d | n~7,299

With 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power the result is 1.0 d | n~7,299. This is not an evanmiller.org sample-size tool.

A/B sample duration
A/B sample duration is this calculator's result. The first example is 1.0 d | n~7,299.
MDE
The formula includes MDE. The second example gives 1.4 d | n~5,634.
sessions
The formula includes sessions. The second example gives 1.4 d | n~5,634.

Examples

Example 1

  • 8000 sessions/day
  • 5 conversion %
  • 2 MDE pp
  • 1.96 Z
  • 1.15 power

1.0 d | n~7,299

With 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power the result is 1.0 d | n~7,299. This is not an evanmiller.org sample-size tool.

Example 2

  • 4000 sessions/day
  • 3 conversion %
  • 1.5 MDE pp
  • 1.65 Z
  • 1 power

1.4 d | n~5,634

With 4000 sessions/day, 3 conversion %, 1.5 MDE pp, 1.65 Z, 1 power the result is 1.4 d | n~5,634.

Example 3

  • 15000 sessions/day
  • 8 conversion %
  • 3 MDE pp
  • 1.96 Z
  • 1.3 power

0.4 d | n~5,027

With 15000 sessions/day, 8 conversion %, 3 MDE pp, 1.96 Z, 1.3 power the result is 0.4 d | n~5,027.

Related calculators

Incrementality

Incrementality: effect = lift × (1 − noise%).

Use calculator →

Attribution window

Attribution window: lift = long − short.

Use calculator →

All agentic commerce calculators

Common questions

What do you get from 8000 sessions/day, 5 conversion %, 2 MDE pp, 1.96 Z, 1.15 power?

1.0 d | n~7,299. This is not an evanmiller.org sample-size tool.

What about the second example?

1.4 d | n~5,634.

What about the third example?

0.4 d | n~5,027.

Is 1.0 d | n~7,299 an evanmiller.org sample-size tool?

No. It is the result from the numbers you enter.

Do empty fields change 1.0 d | n~7,299?

No. Empty scenario fields do not change the result.

How is this different from Incrementality?

That calculator answers another question. Here A/B sample duration stays at 1.0 d | n~7,299.

Does a comma in the number work?

Yes. A comma and a dot mean the same in a number field.

Is the result an invoice?

No. A result from the fields. an evanmiller.org sample-size tool sits outside this calculator.

Do 4000 sessions/day, 3 conversion %, 1.5 MDE pp, 1.65 Z, 1 power give 1.4 d | n~5,634?

Yes. That is the second example under the form.

Knowledge sources

Agent cost is a sketch from your rates. Below are EU, OECD and NIST AI frames, not a contract quote.

Page updated in 2026.