How Long Do You Have to Enforce a Contract in California?

A demand letter isn't itself subject to a legal deadline — you can send one anytime. But it only has teeth if you still have the legal right to sue behind it, and that right expires. Here's California's clock.

The deadline: 4 years written, 2 years oral

Under California Code of Civil Procedure §337, you have 4 years from the date of breach to sue over a written contract. Under §339, an oral contract gives you only 2 years. The gap between those two numbers is one of the clearest reasons to put every business agreement in writing, even an informal one — half your enforcement window disappears if it's oral.

For contracts governed by the Uniform Commercial Code (sales of goods, not services), a separate 4-year rule applies regardless of written or oral form.

When the clock actually starts

The limitations period generally starts running on the date the breach occurred — not when you signed the contract, and not necessarily when you noticed the problem. If a client was supposed to pay by June 1 and didn't, June 1 is your start date, even if you didn't realize the invoice was overdue until months later. California recognizes a "discovery rule" in some circumstances — for concealed or hard-to-detect breaches — but don't count on it rescuing a late claim; assume the clock starts at breach unless a specific exception clearly applies to your situation.

What this means for timing a demand letter

Practically, you want to send a demand letter well before the deadline, not as your last move before it expires. A demand letter sent with three years of runway left signals you're negotiating from strength. A demand letter sent with two months left on a four-year clock signals the opposite — and gives the other side an incentive to stall past your deadline rather than negotiate.

The unpaid invoice scenario

This comes up constantly with unpaid invoices: a written service agreement or signed invoice gives you the full 4-year window under §337. A purely verbal agreement — "we shook hands on the rate" — gives you 2 years under §339, and proving the terms of an oral agreement is harder in the first place. If you're regularly doing business on a handshake, that's the single biggest fix available to protect your own leverage later.

Practical guidance

• Calendar the breach date, not the contract date, as your reference point for any SOL calculation.
• If a dispute is brewing and you're inside the window but it's getting tight, send the demand letter now rather than waiting to see if the relationship resolves itself.
• If the underlying agreement was oral, get whatever documentation you can (invoices, emails confirming terms, texts) — it won't extend the 2-year window, but it strengthens your position within it.

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Need to send a demand letter or cease and desist? Talking Tree's guides on writing a demand letter and collecting on unpaid invoices walk through the process, and Find Counsel can connect you with a California litigation attorney if the deadline is close or the amount is significant.

This article is for general informational purposes only and does not constitute legal advice. Statutes of limitations have exceptions (tolling, discovery rule, contractual modifications) that can change your specific deadline — confirm your situation with a licensed California attorney before relying on any date calculated here.