Calwarden

Evidence Preservation Date Calculator

Estimate a preservation hold-through date and reminder from a trigger date, user-entered preservation window, and review interval.

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Inputs

days
days
days

Your values stay on this device.

Results

Estimated Hold-Through Date
Review Before Date2026-07-17
Method Summary180 entered window days, next review checkpoint 2026-03-03, calendar counting, holiday calendar: ca_courts_2026, weekend handling: none

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Assumptions

  • The trigger date, preservation window, and review cadence are supplied by the user.
  • The calculator assumes the preservation window is measured in calendar days unless the user changes the counting method.
  • Defaults are operational examples only, not preservation law or legal-hold advice.

Sensitivity preview

Preservation Window -10%: Estimated Hold-Through Date 2026-07-13

Preservation Window Current: Estimated Hold-Through Date 2026-07-31

Preservation Window +10%: Estimated Hold-Through Date 2026-08-18

Formula: Estimated hold-through date = preservation trigger date + user-entered preservation window days + manual closure days when included, using the selected counting method and weekend handling. Review before date = hold-through date - reminder buffer days; the review interval is included in the method summary as the next cadence checkpoint.

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About this Evidence Preservation Date Calculator

Estimate a preservation hold-through date and review reminder from your own trigger date and preservation window. Planning estimate/date math only. This is not legal advice, not an official court or agency determination, and it does not verify any rule, order, statute, notice, service method, tolling event, holiday, closure, or jurisdiction-specific requirement. Verify the governing rules, orders, statutes, notices, and counsel before relying on any date. Calculations run locally in your browser; Calwarden does not need to receive or store the dates you enter.

How to use this calculator

  1. Enter the triggering date from the service record, notice, event, letter, or internal calendar.
  2. Enter the response period, preservation window, limitation period, reminder buffer, or recurrence interval from your verified source.
  3. Choose calendar-day, business-day, weekend, and closure assumptions only if those assumptions match the rule or workflow you are checking.
  4. Use the result as a planning date, then verify it against the actual rule, order, statute, notice, and counsel.

Key assumptions

  • The trigger date, preservation window, and review cadence are supplied by the user.
  • The calculator assumes the preservation window is measured in calendar days unless the user changes the counting method.
  • Defaults are operational examples only, not preservation law or legal-hold advice.

Accuracy and testing

Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.

View accuracy page

How this calculator works

Hold-through date = trigger date + user-entered preservation window days. Next review date = trigger date + review interval days. Reminder date = hold-through date - reminder buffer days.
Estimated hold-through date = preservation trigger date + user-entered preservation window days + manual closure days when included, using the selected counting method and weekend handling. Review before date = hold-through date - reminder buffer days; the review interval is included in the method summary as the next cadence checkpoint.

Inputs explained

Triggering date

The user-entered date that starts the planning clock, such as service, notice, event, discovery, letter, or last review date.

Entered period

The editable response period, preservation window, limitation period, demand response period, or recurrence interval you supply from a verified source.

Reminder buffer

An internal lead time subtracted from the estimated due date so you can plan review, filing, preservation, or follow-up before the final date.

Understanding your results

The primary date is the estimated hold-through date for planning. It does not decide scope, custodians, spoliation risk, duty to preserve, retention law, or when a hold may be released.

Example scenarios

Practical example

If a preservation trigger is entered as 2026-02-01, the editable example window is 180 days, and review happens every 30 days, the tool estimates a hold-through date plus a review checkpoint.

Key Features

  • Instant Calculation
  • Private & Secure
  • Mobile Optimized

Things to Keep in Mind

Does not define the preservation duty, evidence scope, retention policy, custodians, litigation hold language, collection method, or release authority.

Tips & Best Practices

  • Save the source document, rule citation, order, notice, or policy that supplied the period you entered.
  • Use earlier internal reminders when missing a deadline would be costly.
  • Check court holidays, emergency orders, service rules, tolling, agency calendars, and counsel before relying on a result.
  • Avoid entering confidential case facts; the math runs locally in the browser, but your own device and policies still matter.

Frequently Asked Questions

Is this calculator legal advice?
No. It is a planning estimate and date-math worksheet only. It is not legal advice, not an official court or agency determination, and not a substitute for reviewing the rule, order, statute, notice, or counsel.
Does this calculator know my jurisdiction-specific deadline rule?
No. You enter the period and counting assumptions yourself. Defaults are editable examples, not authoritative court rules, statutes, or compliance requirements.
Are my dates private?
The calculation is deterministic and runs locally in your browser. Do not enter confidential details unless your own environment and policies allow it.