If a contract doesn't state its own interest rate, California sets the default at 10% per year once payment is overdue (Civil Code § 3289(b)). The same 10% rate accrues automatically on an unpaid small claims judgment (Code Civ. Proc. § 685.010).
It's simple interest: calculated on the original amount only, every year, it does not compound on top of interest already accrued. A calculator offering "simple or compound" for California is offering you a number that doesn't match what a judge would actually apply, this one only offers the correct method.
If your contract specifies its own interest rate in writing, that rate can apply instead. Change the rate field to match it.
Turn what happened into a formatted demand letter, free, with the exact amount you're owed.
Write my letter, free →Generally 10% per year, simple interest, not compounded. That's the default legal rate when a contract doesn't specify its own rate (Civil Code § 3289(b)), and it's also the rate that accrues automatically on an unpaid small claims judgment (Code Civ. Proc. § 685.010).
Simple. California's statutory 10% rate is calculated on the original principal only, it does not compound on top of previously accrued interest. This calculator only offers simple interest because that's what actually applies.
Just California. The 10% default rate it uses is specific to California statute and would be wrong for most other states.
Yes. It runs entirely in your browser, nothing you enter is sent to or stored by SmallClaimsHQ.