Expert witness exchange date
50 days before initial trial date (and date the demand was served), under Cal. Code Civ. Proc. 2034.230(b).
Rule text
The specified date of exchange shall be 50 days before the initial trial date, or 20 days after service of the demand, whichever is closer to the trial date, unless the court, on motion and a showing of good cause, orders an earlier or later date of exchange.
Calculate this deadline
- Trigger (Initial trial date (and date the demand was served)): Friday, November 6, 2026.
- Count back 50 calendar days: Thursday, September 17, 2026.
Cal. Code Civ. Proc. 2034.230(b)
The specified date of exchange shall be 50 days before the initial trial date, or 20 days after service of the demand, whichever is closer to the trial date, unless the court, on motion and a showing of good cause, orders an earlier or later date of exchange.Official source
Cal. Code Civ. Proc. 12, 12a, 12b, 10; Cal. Rules of Court, rule 1.10
CCP 12: "The time in which any act provided by law is to be done is computed by excluding the first day, and including the last, unless the last day is a holiday, and then it is also excluded." CCP 12a(a): "If the last day for the performance of any act provided or required by law to be performed within a specified period of time is a holiday, then that period is hereby extended to and including the next day that is not a holiday. For purposes of this section, “holiday” means all day on Saturdays, all holidays specified in Section 135 and, to the extent provided in Section 12b, all days that by terms of Section 12b are required to be considered as holidays." CCP 12b: "If any city, county, state, or public office, other than a branch office, is closed for the whole of any day, insofar as the business of that office is concerned, that day shall be considered as a holiday for the purposes of computing time under Sections 12 and 12a." CCP 10: "Holidays within the meaning of this code are every Sunday and any other days that are specified or provided for as judicial holidays in Section 135."Official source
- Compute both (a) initial trial date - 50 days and (b) service of demand + 20 days (CCP 1013/1010.6 extension arguably applies to the 20 days after service via 2016.050; AMBIGUITY); the exchange date is whichever is closer to trial. The demand itself must specify the date. Supplemental expert list: within 20 days after the exchange (CCP 2034.280(a)).
- If the clerk's office is closed or inaccessible on the last day (weather, emergency or local closure orders), the deadline may be extended. Check local orders.
This calculator applies the cited rules to the dates you enter. It is not legal advice. Court orders, local rules, and case-specific facts can change a deadline; verify before relying on it. Rule set pending attorney review.
Worked example
Initial trial date (and date the demand was served) on Monday, March 15, 2027, personal service: due Monday, January 25, 2027.
- Trigger (Initial trial date (and date the demand was served)): Monday, March 15, 2027.
- Count back 50 calendar days: Sunday, January 24, 2027.
- That day is a Sunday, so the deadline moves to the next court day closer to the event, per the rule cited for this deadline: Monday, January 25, 2027.
Notes
Compute both (a) initial trial date - 50 days and (b) service of demand + 20 days (CCP 1013/1010.6 extension arguably applies to the 20 days after service via 2016.050; AMBIGUITY); the exchange date is whichever is closer to trial. The demand itself must specify the date. Supplemental expert list: within 20 days after the exchange (CCP 2034.280(a)).
Related deadlines
- Responses to interrogatories (30 days after)
- Responses to requests for production (inspection demands) (30 days after)
- Responses to requests for admission (30 days after)
- Unlawful detainer: responses to interrogatories, inspection demands, requests for admission (5 days after)
- Motion to compel further responses (interrogatories, inspection demands, RFAs) (45 days after)
- Discovery cutoff (complete discovery) (30 days before)
- Discovery motion cutoff (last day for hearing) (15 days before)
- Demand for exchange of expert witness information: last day (70 days before)
Local rules by county
County local rules and courtroom procedures can add to or change this deadline. Pick a county to calculate with them applied.
- Alameda
- Alpine
- Amador
- Butte
- Calaveras
- Colusa
- Contra Costa
- Del Norte
- El Dorado
- Fresno
- Glenn
- Humboldt
- Imperial
- Inyo
- Kern
- Kings
- Lake
- Lassen
- Los Angeles
- Madera
- Marin
- Mariposa
- Mendocino
- Merced
- Modoc
- Mono
- Monterey
- Napa
- Nevada
- Orange
- Placer
- Plumas
- Riverside
- Sacramento
- San Benito
- San Bernardino
- San Diego
- San Francisco
- San Joaquin
- San Luis Obispo
- San Mateo
- Santa Barbara
- Santa Clara
- Santa Cruz
- Shasta
- Sierra
- Siskiyou
- Solano
- Sonoma
- Stanislaus
- Sutter
- Tehama
- Trinity
- Tulare
- Tuolumne
- Ventura
- Yolo
- Yuba
Rules current as of 2026-10-25. Confirm against the official source and any local rule or court order before relying on a date. Rules changelog.