Operational Planning Tool
Enrollment Forecast Calculator
Estimate clinical trial enrollment velocity, projected study completion timelines, and the referral volume required to meet enrollment targets on schedule. To understand which specific operational drivers — intake velocity, prescreening throughput, handoff quality, and enrollment rate consistency — contribute most to your timeline, see how enrollment operations impact study timelines.
Enrollment Inputs
Adjust to reflect your site's referral volume, conversion rates, and study parameters.
Conversion Rates
Enrollment Forecast
31.6
Monthly Enrollments
Participants reaching randomization per month
1.6
Months to Complete
At current enrollment velocity
39.5%
Referral Conversion
Referrals reaching randomization
11
Required Referrals/Mo
To hit target within study duration
On Track to Hit Target
At current velocity, enrollment target reached in 2 months vs. 12-month study duration.
Enrollment Velocity
High VelocityExcellent velocity indicating highly optimized operations and strong pipeline management.
Monthly Enrollment Timeline
Cumulative enrollment progression at current velocity. Target reached when cumulative enrolled equals enrollment target.
| Month | Cumulative Enrolled | Progress to Target |
|---|---|---|
| Month 1 | 31.6 | |
| Month 2Target | 50 | |
| Month 3 | 50 | |
| Month 4 | 50 | |
| Month 5 | 50 | |
| Month 6 | 50 |
Improvement Scenario Comparison
How changes to conversion rates or referral volume shift enrollment velocity and projected completion.
Current pace
31.6
enrollments/month
2 mo
to completion
+10% conversion improvement
+14.1/moAll conversion rates ×1.10
45.7
enrollments/month
2 mo
to completion
+20% conversion improvement
+24.6/moAll conversion rates ×1.20
56.2
enrollments/month
1 mo
to completion
+25% referral volume increase
+7.9/moSame conversion rates, more referrals
39.5
enrollments/month
2 mo
to completion
How to Use This Calculator
Enter your actual conversion rates
The calculator is only accurate when you enter your site's real performance data. Idealized rates produce misleading forecasts. Use actual intake completion percentages, prescreening pass rates, and scheduling success data from recent study operations.
Use the required referral output to identify supply gaps
The required referrals per month metric tells you how many monthly referrals are needed to hit your enrollment target on time. If this exceeds your current volume, you have a supply gap that must be addressed through increased referrals, improved conversion rates, or both.
Compare scenarios to choose your improvement path
The scenario comparison shows whether improving conversion rates or increasing referral volume will have a greater impact on your timeline. For most sites, conversion rate improvement produces faster gains with less external dependency. For the specific process levers that drive conversion improvement, see the guide on improving enrollment performance without increasing referrals.
Use stage-specific tools for deeper analysis
This calculator models four combined enrollment stages for timeline forecasting. For granular stage-by-stage loss analysis — including intake, handoff, scheduling, and consent stages — use the Referral to Randomization Calculator.
Related Resources
Improve the Inputs Behind Your Forecast
Frequently Asked Questions
Common questions about enrollment forecasting and how to use this calculator.
If your enrollment forecast reveals a timeline risk or performance gap, an Enrollment Alignment Call provides a direct review of your intake, prescreening, and coordinator capacity systems. If your forecast shows a conversion gap rather than a volume gap, see improving enrollment performance without increasing referrals for the process-level interventions that address it.