Sample Size Calculator for Rates

Plan sample size for event rates where exposure time matters. Specify your expected rate, desired margin of error, and confidence level. The calculator converts the required exposure into subjects automatically when you provide exposure per subject.

Great for

• Incident or defect rates per machine hour or per patient year
• Reliability studies where exposure time varies by subject
• Estimating Poisson-like counts with a clear precision target

Inputs to set

• Confidence level
• Expected rate (events per exposure unit)
• Target margin of error for the rate
• Exposure per subject to translate into headcount