• Calculate Quick & Easily 
    No coding necessary, nQuery Sample Size Calculator's intuitive and easy to use interface allows you to calculate power & sample size quickly and accurately. Our sample size statement generator automatically writes up your sample size statement in the correct language & format for submission to regulatory agencies and peer-reviewed publications.
  • Complete Confidence
    Partnering with Big Pharma and Top 10 CRO's for 20 years, we know every trial design scenario, so you can calculate sample size with complete confidence. With 100’s of validated sample size procedures and 50,000 users worldwide you can trust nQuery Advisor.
  • Industry Favorite for Regulatory Approval
    Sample size calculation is a small but vital part of the study design. You can rely on nQuery, the most trusted sample size calculator, proven over 1000’s of successful clinical trials.

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nQuery is trusted by all the relevant parties in clinical trials: Sponsors, CRO's & Regulatory Agencies.

Choose nQuery to ensure you offer your clients the very best in sample size calculation and power analysis software. 


One of clients (Top 5 CRO) had already been using nQuery Sample Size Calculator successfully for 12 years, at multiple locations worldwide. One of their lead statisticians contacted us with a specific issue they were trying to solve. The problem was centered around the creation of randomization lists using mixed block sizes in clinical trials. The lead statistician felt that there was a possibility of introducing bias when using fixed block sizes in clinical trials. 

The company had attempted to develop SAS macro's to solve the problem, but found that these macro's had serious limitations, were cumbersome to use and most importantly could not accommodate the mixed block size design.

We worked closely with this CRO to develop the required mixed block sizes functionality including:

  • Assignment of Subjects using Mixed Block Sizes
  • Expanded Facilities for multiple Strata/Factor Specification
  • Improved Output Options for the Randomization Lists
  • Fully version controlled randomization list output

This fully validated functionality was developed quickly and rolled out to the CRO's userbase within 4 months. As a result of this cooperation with a world-class CRO, this much-needed functionality is now available in nQuery and is used and appreciated by our other CRO clients.

“I strongly support your development of this random block generator, as there seems to be a lack of software that will do it and I believe it's worth doing.”

Lead Statistician, Top 5 CRO

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