A/B Pre-test Calculator by Speero

Speero's A/B Pre-test Calculator helps you answer vital pre-test questions like MDE, sample size, duration, and more.

As of May 2026, A/B Pre-test Calculator by Speero has 1,000 users in the Developer Tools category.

Usersno change0%
1.0K
1,000
Ratingno change0%
— reviews
Reviewsno change0%
Version
1.4
Manifest V3

Permissions & access

Permissions
storageidentity
Host access
https://accounts.google.com/o/oauth2/token

Screenshots

A/B Pre-test Calculator by Speero screenshot 1A/B Pre-test Calculator by Speero screenshot 2A/B Pre-test Calculator by Speero screenshot 3

About

Speero's A/B Pre-test Calculator helps you answer all important pre-test questions like:

— What is the minimal detectible effect I can test for?
— How long should I test for considering the effect?
— What's the sample size?

— How to use Speero's A/B Pre-test Calculator? — 

Type in the number of weekly sessions or users, conversions, and a number of test variants, and see if your website has the capacity to test your ideas.

Or just sign in with Google Analytics and let Speero’s calculator get the results for you.

Speero’s A/B Pre-test Calculator is pre-defined for 2 variants (including control), confidence of 95% and statical power of 80%.

— Why Speero’s A/B Pre-test Calculator? — 

One of the best A/B Pre-test Calculators, now in Plugin mode.

Determine sample size, MDE, and test duration on the go.

Filter By Page Path and compare pre-test data from multiple URLs.

The best part is that Speero’s A/B Pre-test Calculator connects with your GA4, letting you answer all your pre-test questions without leaving the tab.

Technical

Version
1.4
Manifest
V3
Size
41.2KiB
Min Chrome
88
Languages
1
Featured
No

Metadata

ID
lmcdffjpijcfeamjmldmdncejdnifgdf
Developer ID
ucd69b9473f58770e1c82b7c266481a06
Developer Email
[email protected]
Created
Aug 9, 2023
Last Updated (Store)
Feb 8, 2024
Last Scraped
May 29, 2026
Support URL

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Data sourced from the Chrome Web Store · last verified May 29, 2026.