What must a new party know within Chancery’s relation-back notice window?

Filing of the original complaint

Identify the new party’s actual notice and knowledge. The calendar does not determine a qualifying identity mistake or prejudice to the defense.

Responsible actor. The party relying on relation back when changing the defendant or its name. Compute only the ordinary 120-day notice-and-knowledge window. Independently establish the same-conduct claim, lack of prejudice, qualifying mistake and no court-granted extra time.

1. Compute only the ordinary 120-day notice-and-knowledge window. Independently establish the same-conduct claim, lack of prejudice, qualifying mistake and no court-granted extra time.
2. Exclude the trigger day and count 120 calendar days under Rule 6(a)(1). The less-than-11-day exclusion does not apply. Check the final weekend, legal holiday and actual Register accessibility.
3. Check the actual holidays, additional closures and applicable electronic or paper boundary.
4. Preserve the complaint filing and evidence that both notice and required knowledge occurred within the qualifying window. File the amendment through the separate amendment procedure.

Rule 6(a)(1) excludes the event day. Periods below eleven days exclude intermediate Saturdays, Sundays and legal holidays; eleven days or more include them. A final weekend or legal holiday moves forward for an after-event period and backward for a before-event period. Rule 6(a)(3) separately addresses actual Register inaccessibility for filings. Rule 6(a)(5) includes section 501 holidays and days declared by the Governor. Good Friday and Thanksgiving Friday are Delaware holidays. Sunday July 4, 2027 is observed Monday July 5. Check county-specific Sussex Return Day and additional actual closures separately; the bundled calendar does not determine those filing conditions.

Rule 6(c) adds three calendar days after the ordinary Rule 6(a) period only for an act measured after service made exclusively by mail. It applies to party acts, not Court acts. Electronic service, an entry-based clock and a filing-based clock do not acquire that addition merely because a paper copy is mailed. These calculations show the disclosed nonexclusive-mail base component; they do not implement the mail-only addition or infer service effectiveness.

These reviewed calculators use the official edition current as of June 1, 2026. Events before that date and backward periods crossing before that date receive no computed or paid date. This is publication coverage, not a finding that an actual procedural act is late. Historical editions, emergency measures, court-modified dates and actual additional closures require separate review.

Fictitious example

Compute only the ordinary 120-day notice-and-knowledge window. Independently establish the same-conduct claim, lack of prejudice, qualifying mistake and no court-granted extra time. Ordinary current-edition facts, no changed order and no exclusively mailed incoming service.

Fictitious current-edition facts. This is the disclosed component with no altered order or additional actual closure. It does not establish effective service, completed filing, judicial action or procedural entitlement. Exclusively mailed incoming-service additions require separate review.

Same underlying conduct

The changed-party branch requires Rule 15(c)(2)’s same conduct, transaction or occurrence condition.

Additional time

The Court may allow additional time for good cause. This base calculation does not grant it.

Mail-only service and actual court schedule

Rule 6(c) adds three calendar days after the ordinary Rule 6(a) period only for an act measured after service made exclusively by mail. It applies to party acts, not Court acts. Electronic service, an entry-based clock and a filing-based clock do not acquire that addition merely because a paper copy is mailed. These calculations show the disclosed nonexclusive-mail base component; they do not implement the mail-only addition or infer service effectiveness.

Current edition and historical scope

These reviewed calculators use the official edition current as of June 1, 2026. Events before that date and backward periods crossing before that date receive no computed or paid date. This is publication coverage, not a finding that an actual procedural act is late. Historical editions, emergency measures, court-modified dates and actual additional closures require separate review.

• Compute only the ordinary 120-day notice-and-knowledge window. Independently establish the same-conduct claim, lack of prejudice, qualifying mistake and no court-granted extra time.
• The base calculation does not obtain an extension, resolve a different branch or establish that the responsible actor completed the required act.

• Filing of the original complaint
• Identify the new party’s actual notice and knowledge. The calendar does not determine a qualifying identity mistake or prejudice to the defense.
• The changed-party branch requires Rule 15(c)(2)’s same conduct, transaction or occurrence condition.
• The Court may allow additional time for good cause. This base calculation does not grant it.
• Preserve the complaint filing and evidence that both notice and required knowledge occurred within the qualifying window. File the amendment through the separate amendment procedure.
• For electronic service and filing, Rule 5(d) uses midnight for an original complaint, notice of appeal, or paper in a summary proceeding or an action ordered expedited. Other papers in other actions must be served or filed by 5:00 p.m. Use Delaware local court time and preserve actual completed transmission and docket treatment. Do not replace the ordinary boundary with a federal midnight rule. Rule 5(c)(2)(B) permits self-represented delivery to the Register with the required fee, deemed filed when delivered. Check actual office availability. Rule 5(e) permits the Court, on satisfactory proof, to deem an unsuccessful electronic attempt timely; relief is not automatic.