Pro-Rated Rent Formula: We divide your monthly rent by the total number of days in the move-in month to determine a daily rate. That daily rate is then multiplied by the number of days you will occupy the unit (from your move-in date through the last day of the month). For example, if your rent is $1,800 and you move in on March 10th in a 31-day month, your daily rate is $1,800 / 31 = $58.06, and your pro-rated rent is $58.06 x 22 days = $1,277.42.
Late Fee Calculation: Washington state (RCW 59.18) does not impose a statutory cap on late fees, unlike Oregon. However, landlords must provide 14 days written notice before charging late fees, and courts may find excessive fees unreasonable. Our calculator applies the fee based on your lease terms and flags the 14-day notice requirement.
Data Sources: All calculations follow the Washington Residential Landlord-Tenant Act (RCW 59.18) as of 2026. We recommend verifying your specific lease terms, as individual agreements may include provisions beyond the statutory baseline.
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Compare Renters Insurance →Pro-rated rent in Washington is a partial month's rent calculated based on the number of days you occupy the rental unit during that month. This commonly applies when a tenant moves in or out mid-month.
Divide your monthly rent by the total number of days in the month to get a daily rate, then multiply that daily rate by the number of days you will occupy the unit.
Washington state law (RCW 59.18) does not explicitly require landlords to pro-rate rent. However, most landlords will pro-rate when a tenant moves in mid-month. Always check your lease agreement for specific terms.
Washington state does not impose a statutory cap on late fees, unlike some other states. However, landlords must provide 14 days written notice before charging late fees, and courts may find excessive late fees unreasonable. Late fee terms should be outlined in your lease agreement.
Washington tenants have rights under the Residential Landlord-Tenant Act (RCW 59.18), including protections regarding habitability, notice requirements for rent increases, security deposit limits, and the right to written notice before late fees are assessed.