Study Duration

Study Duration Calculator

Estimate key study milestones from First Site Initiation (FSI), First Patient In (FPI), recruitment duration, treatment, follow-up and database lock lag.

Calculator

Enter study assumptions

First Site Initiation (FSI) — optional Enter the planned or actual date of the first site initiation. This is separate from site activation and FPI. First Patient In (FPI) Enter the planned or actual date the first patient is enrolled/randomised. Recruitment duration (months) Enter the planned number of calendar months from FPI to Last Patient In (LPI). Treatment duration (weeks) Enter the planned treatment period for the last patient enrolled. Follow-up duration (weeks) Enter any follow-up period after treatment ends for the last patient. DBL lag after LPLV (weeks) Enter the planned time from Last Patient Last Visit to Database Lock.

Methodology

How study dates are calculated

First Site Initiation (FSI)

Shown directly from the optional date you enter; FSI is not calculated from FPI.

First Patient In (FPI)

Shown directly from the date you enter; this remains the start of the FPI-to-DBL duration.

Last Patient In (LPI)

FPI + recruitment duration in calendar months

Last Patient Last Visit (LPLV)

LPI + treatment duration + follow-up duration

Database Lock (DBL)

LPLV + DBL lag

Total study duration

Time from FPI to DBL, shown in approximate months and exact calendar days.

Scope

A high-level planning timeline

FSI is an optional, separately entered milestone and is not assumed to be the site activation or FPI date. This calculator assumes the last patient receives the full planned treatment and follow-up periods after LPI. Recruitment duration is treated as calendar months; treatment, follow-up and DBL lag are entered in weeks. Total study duration remains measured from FPI to DBL.

Planning tool only. Actual milestone dates may be affected by protocol windows, treatment interruptions, long-term follow-up, data cleaning strategy and operational delays.