A lease extension agreement continues an existing tenancy for a further defined period on the same terms, or on stated changed terms. It is the right instrument when nothing much is changing and the wrong one when a great deal is. This page is when to use it, what it must say, and the date that is most often got wrong.
Extension or renewal
An extension continues the existing lease; a renewal creates a further term, often by a new document. Practically the difference is how much is changing. If the answer is the end date and possibly the rent, an extension is cleaner and keeps the original lease as the operative document. If terms are being reworked, a renewal or a fresh lease is more honest than an extension carrying six amendments.
What it must state
Which lease, identified by property, parties and date. The new end date. The rent for the extended period and the date it applies from. A sentence confirming all other terms continue. And signatures from everyone who signed the original, including any guarantor, because a guarantor who did not sign the extension may not be guaranteeing it.
The date people get wrong
The date the new rent takes effect, which is often not the first day of the extended term. If the extension is signed in advance and the rent changes at the start of the new term, say both dates. If the rent changes mid-extension, say that too. This single ambiguity produces more awkward conversations than any other line in the document, and it takes one clause to remove.
The guarantor question
If someone guaranteed the original term, check whether their guarantee extends, and if it should, have them sign. An extension executed without the guarantor is a common oversight that is invisible until it matters, at which point the landlord discovers the security they thought they had ended with the original term.
Questions people ask about lease extension agreement
Can a lease be extended by email?
Sometimes it will be effective and it is a poor idea, because the email rarely identifies the lease, states both dates and captures the guarantor.
How far ahead should an extension be signed?
Far enough that both sides still have alternatives, which for most residential tenancies means a couple of months before expiry.
Does an extension reset anything?
Not by itself. The original lease and its addenda continue, which is the reason to use an extension when that is what you want and a new lease when it is not.