CRC ToolboxVisit Window Calculator

100% client-side & Zero-PHI:Data stays in your local browser storage. Client-side processing by design — avoids server-side PHI ingestion. No login required.

Visit Window Calculator

Compute target visit dates and ± windows from an anchor date — calendar math only, never subject identifiers.

Calculate Protocol Visit Windows From an Anchor Date

Every protocol defines visit windows as an offset from an anchor date — day 1, randomization, last dose — and manually counting out a ± window for each scheduled visit is tedious and easy to get slightly wrong, especially across multiple subjects with different anchor dates.

Visit Window Calculator takes an anchor date and the protocol's defined window and returns the full visit schedule with allowable ranges — a quick reference for scheduling without redoing the math by hand every time.

Calculations run entirely in memory in your browser — nothing is stored or transmitted, no login required.

Who this is for: CRCs scheduling protocol visits and confirming a visit falls within window before it's logged as a deviation.

Site workspace backup

Saved in this browser’s localStorage on this PC — export before switching workstations; clear on shared kiosks when done.

Download works without an email — nothing ever uploads.

1. Inputs

Use a protocol anchor only (baseline / randomization / cycle start). Do not enter subject IDs, names, or initials.

2. Window result

Enter a valid anchor date, or load the sample.

3. Quick schedule generator

Builds a recurring visit table from the same window limits. Saved with this workstation workspace.

FAQ for this tool

Administrative reference only. Browser-local tools — not a medical device, CDSS, or Part 11 system. Verify outputs against protocol SOPs and primary site records. Zero-PHI local mode: do not enter names, MRNs, DOBs, or subject IDs. Study / kit / lab / deviation / IP accountability / equipment / regulatory / visit drafts use this workstation's localStorage until you clear them. On shared clinic PCs, clear all local site data when finished.