Rent Increase Calculator

Under the Residential Tenancies Act, rent for an existing tenancy can only be increased once at least 12 months have passed since the last increase (or since the tenancy started, if it's never been increased). That threshold doesn't reset each year, once it's passed, you stay eligible until you actually use it. Tenants must also get at least 60 days' written notice before the new rent takes effect.

This is general information, not legal advice. Some tenancies (e.g. certain fixed terms, or rent set by a Tenancy Tribunal order) have different rules. Check tenancy.govt.nz for your situation.