Since 2025, Washington law limits how much you can raise rent in a 12-month period. This tool shows the cap that applies to your increase and the highest new rent the law allows, so you can price a renewal without accidentally going over.
House Bill 1217 (2025) put a statewide ceiling on annual rent increases. Each year the Department of Commerce publishes the cap as the lesser of 7% plus inflation or 10%. For 2026 that figure is 9.683%; for 2027, Commerce set it at a flat 10% (the formula produced 11.53%, so the statutory ceiling binds).
The cap that governs your increase is the one in force on its effective date, not the day you serve notice. So a renewal increase taking effect in December 2026 is capped at 9.683%, while one taking effect in January 2027 is capped at 10%, even if you serve both notices this summer.
The cap is the maximum total increase across any rolling 12-month period, not per notice. It also can't apply at all during a tenant's first 12 months: Washington prohibits any increase in the first year of a tenancy.
Some properties are exempt, most commonly new construction (certificate of occupancy issued within the last 12 years) and certain owner-occupied small buildings. This tool flags the exemptions worth checking, but it can't confirm one applies to you; that's a question for the statute or an attorney.
Two scope notes: manufactured and mobile home lot rents have their own, separate 5% cap under the same law, which this calculator does not compute. And some Washington cities (Tacoma, Burien, Olympia, Bellingham, and others) layer stricter local notice and relocation rules on top of the state cap, so a cap-compliant increase can still require more notice locally.
You only need two facts. Here's what each one is for:
Current monthly rent. The rent your tenant pays today, before the increase. The cap percentage is applied to this number to find your ceiling.
Planned effective date. The day you want the new rent to begin. Because the cap is set per calendar year, the effective date decides which year's percentage governs your increase.
That's GiveProperNotice: the full deadline calendar, checklist, and reminder emails, for $99 a year.
Working out a Seattle increase? Use the notice deadline calculator to find the last day you can serve notice for that effective date.
Each year the Department of Commerce publishes the cap as the lesser of 7% plus inflation, or 10%. For 2026 it is 9.683%. For 2027 Commerce set it at a flat 10%, because the formula produced 11.53% and the statutory ceiling binds.
The cap in force on the effective date governs, not the day you serve. An increase taking effect in December 2026 is capped at 9.683%, and one taking effect in January 2027 is capped at 10%, even if you serve both notices in the same summer.
It is the maximum total increase across any rolling 12-month period, not per notice. Two smaller increases inside a year are added together. No increase at all is allowed during a tenant's first 12 months.
No. The most common exemptions are new construction, where the certificate of occupancy was issued within the last 12 years, and certain owner-occupied small buildings. Manufactured and mobile home lot rents have their own separate 5% cap. This tool flags the exemptions worth checking but cannot confirm one applies to you.
