What are the two proration methods?

30-day-month method: monthly rent ÷ 30 × days occupied. Actual-day method: monthly rent ÷ actual days in that month × days occupied. The 30-day method is administratively cleaner; the actual-day method is more mathematically precise. California doesn't mandate one method — but the lease should specify.

Does the law require proration?

No statutory requirement. By common practice and lease convention, landlords prorate mid-month move-ins. Some leases require first month full and prorate the second month. Either approach is enforceable if clearly stated in the lease.

What about mid-month move-outs?

If tenant gives proper §1946 notice ending mid-month, rent is usually prorated through the termination date. If tenant skips out without notice, the holdover/abandonment analysis applies — different framework.

What about §1946 notice that extends beyond month-end?

Tenant who serves 30-day notice on day 15 of the month must pay through day 15 of the following month — proration applies to the back end. The lease should state which day-count method applies.

What's a standard lease clause?

Specify the method (30-day or actual-day), the trigger (move-in, move-out, mid-cycle change), and the rounding convention. Avoid ambiguity. Disputes over a few dollars of proration aren't worth the friction.

30-day vs actual-day · Mid-cycle

Rent proration. Two methods. Pick one. State it in the lease.

30-day-month is administratively cleaner. Actual-day is more precise. California doesn't require either — but the lease must specify to avoid dispute.

TL;DR

30-day method (÷30) or actual-day method (÷actual days in month). Pick one in the lease. Mid-month move-in: prorate. Mid-cycle termination after §1946 notice: prorate through end date. Skip-out: holdover analysis, not proration.

Lease Agreements
30-Day Notice

Common questions — proration

Two methods?

30-day or actual-day.

Required?

No statute; convention.

Mid-month move-out?

Prorate through termination date.

Notice extending past month-end?

Prorate back end.

Lease language?

State method explicitly.