What is the Commercial Lease Commencement Date?
- Jason Jackson
- Jun 19
- 8 min read
Updated: Jul 7
Every commercial lease is different, and yours decides the fate of your practice. So before anything else, read your lease.
Inside your lease is one small date that controls your most important deadline, which is the day you have to tell your landlord you want to stay. Miss that deadline and you can lose your space, and possibly your medical practice.
Most dental, optometry, and veterinary practice owners cannot name that date. If that is you, you are normal, and it is not your fault.
That date is your lease commencement date. This article breaks down how this one date sets your deadline to stay in your space, why your start date may not be the day you took possession, how these dates can quietly shift, and the exact records you need to protect your medical practice years later.
When Did Your Commercial Lease Commence
When you opened your practice, you were not studying lease definitions. You were busy. You had to manage patients, hire administrative staff, and navigate complex clinical regulations.
You may have been working as an associate at another clinic while constructing your new dental or medical practice. If you did not hire anyone to oversee the build out, you carried the entire load alone, managing the bank, designer, contractor, equipment reps, and constant back and forth with the landlord.
So your lease commencement date slipped past you. Then time goes by. And depending on your lease, you could have secured a lengthy lease term for five, ten, or more years. Because healthcare practices require significant capital investments, these long term lease commitments can be necessary. You naturally assume the contract remains secure indefinitely.
The trouble is that this one quiet date controls your most important deadline. Pinning down this exact date is vital.
When Does Your Lease Expire
Your lease has a start date and an end date. To track your deadline, you need to understand three simple parts of a lease timeline:
The start date: your lease commencement date.
The end date: your lease expiry date.
The lease length: the fixed number of months or years your practice is secured in the space.
To stay in your space after the lease ends, you must notify your landlord that you want to exercise your option to renew or extend. This notice cannot be sent whenever you like. You must deliver your renewal or extension notice within a specific time frame before your lease expires, known as your notice window. This window is non negotiable and strictly enforced.
Here is the part that catches doctors. Your expiry date is calculated from your lease commencement date. So if you do not know your true start date, you will calculate the wrong expiry date. Get the expiry date wrong and you get the notice window wrong. You will believe you have months to exercise your option to stay, when your window has already closed.
Or, you might send the notice too early. Deliver the notice outside the extension or renewal window and the landlord has no obligation to accept the notice or flag the error. The landlord can simply ignore the paperwork. You will think your practice and lease is safe, when legally, no valid notice was ever given.
Your landlord is not going to help you.
The One Rule Behind These Dates
Every lease is different. The exact words in your signed lease matter more than anything in this article.
Your fully executed lease, the final version everyone signed, is your guide. What follows tells you what to look for inside your lease.
What is a Fixed Lease Commencement Date?
Some leases state a fixed calendar date for your commencement and your expiration, written in plain language. If your contract does this, tracking your timeline is easy, because the paperwork does the math for you. You simply use that exact expiration date to find your notice window.
Example:
Lease commencement date (start): May 1, 2023
Lease expiration date (end): April 30, 2033
Lease term length: 10 years
Notice language in the lease: no sooner than 6 months and no later than 3 months before the expiration date
Your notice window: October 30, 2032 to January 30, 2033
Unfortunately, not all leases work this way. Instead of fixed dates, some leases use a timeline mechanism. This mechanism is exactly where good doctors get caught.
What is a Floating Lease Commencement Date?
In these leases, the commencement date is not a set calendar day. Instead, the contract says your lease officially starts on the earlier or later of an event.
These events could include:
The day your healthcare practice opens for business.
The day after your fixturing period ends.
Or another specific event named in your lease.
On the day you sign the lease, nobody knows the exact start date. They cannot, because the triggering event has not happened yet. Because the start date is triggered by an event, the lease commencement date becomes a floating target.
The Domino Effect of a Floating Lease Commencement Date
This floating lease commencement date sets off a chain reaction through your entire contract. Instead of fixed calendar dates from day one, the lease just states a length of time, like ten years.
Your ten year clock only starts ticking once that floating lease commencement date is triggered. If your start date moves, your end date moves with it. You are handling a completely floating term.
The Shifting Lease Renewal Notice Window
Here is the catch with a floating term. Because your start date floats, your end date floats with it. Your landlord still holds you to a strict notice window, counted back from that end date. So if you do not pin down the exact commencement date, you cannot know when your lease ends, and you miss your lease extension or lease renewal notice window.
Why a Floating Lease Commencement Date is Good
A floating start date can actually be a massive win for your practice. If an expert negotiated your lease, they likely built in that floating date on purpose. A floating start date can protect you from paying rent on an empty space if your construction drags or permits stall. Landlords want rent checks rolling in on day one. A properly negotiated floating lease commencement date means someone fought for you.
Why a Floating Lease Commencement Date is Bad
But that same floating target that benefited your practice at the beginning makes your lease security fragile. A floating date is not a minor legal technicality. The risk to your medical practice is absolute. Your option to stay in the building has to be exercised inside that precise lease extension or lease renewal notice window. Miss that window, and your right to stay and leverage is completely gone.
Why You Need to Keep Lease Records
A five or ten year lease feels long on the day you sign. The years go faster than you think.
By the time your lease notice window opens, the building may have been sold. There may be a new owner or a new property manager, and the person across the table may have no memory of your transaction, and no reason to be kind about your dates. They will review the bare text of the contract to find any leverage they can against your business.
A new owner or manager can test your commencement date. If your records are loose or missing, they may pick the date that suits them, and you are left arguing from a memory that is ten years old.
So build a simple commercial real estate file the day you take possession, and keep it for the life of your lease.
A Pro Tip: Keep One Steady Email
Here is something learned after more than ten years working with healthcare professionals.
Practice owners tend to use several email addresses, throwaway accounts, or an old address left over from university. If people cannot reach you, they cannot help you. I have emailed clients to remind them of these exact commencement and notice dates, or just to check in, only to find the address was shut off. I rarely see this with other entrepreneurs or small business owners, but it is very common in healthcare.
So pick one email, keep it, and watch it. An email that saves your lease has to be able to reach you.
What You Should Do With Your Commercial Lease Commencement Date
What you should do depends on which kind of lease you have. Figure out which one is yours, then follow the matching steps.
If your lease commencement date is fixed:
Read your lease and calculate your renewal or extension notice window.
Email your landlord to confirm they have the same dates, and save the email.
Put both ends of your notice window in your calendar, with early reminders.
Then relax and go run your practice.
If your lease commencement date is floating:
Ask your landlord for an email or a notice of commencement that states your exact commencement date.
Read your lease and calculate your renewal or extension notice window from that date.
Email your landlord to confirm they have the same dates, and save the email and keep it so you have a written record to fall back on.
Should your landlord not respond to your email, send them a formal email stating your commencement date, then print that email and keep it so you have a written record to fall back on.
Put both ends of your notice window in your calendar, with early reminders.
Then relax and go run your practice.
If you are negotiating a brand new lease:
Do not wait until your lawyer is drafting the lease to lock in the commercial lease structure. Your leverage exists entirely during the offer stage, not when the final legal text is being written. Ensure your commercial real estate representative secures the exact structure you want before it ever hits a lawyer's desk.
Pro Tip: The better the lease clauses are drafted during the offer stage, the more you'll save on legal fees because your lawyer isn't having to do as much heavy lifting.
The Bottom Line
Your lease commencement date is small and easy to ignore, right up until the day you want to stay.
Know the day your lease clock actually started, so you can pin down your lease renewal or extension notice window. Keep the records that prove the date. Do that, and no landlord can move the goalposts on you years later.
If a renewal or extension is on your horizon and you want the dates and the transaction handled right, that is the work Attridge Group does for dental, medical, optometry, and veterinary practices across the US and Canada.
Help Protect Your Healthcare Community
Do you have a colleague, or friend in the healthcare community whose practice might be at risk?
Please share this article with them. Lease renewal and extension dates are critical pieces of information that simply aren't taught in school. Make sure they have the knowledge they need, so a missed deadline doesn't cost them their practice.
Common Lease Commencement Date Questions
What is a commercial lease commencement date?
Your lease commencement date is the day your lease clock starts. Your expiry date and your renewal notice window are both counted from this date. Your lease commencement date might tie the date to an event, or a fixed calendar date.
Is my commencement date the same as my possession date or the day my rent starts?
Not always. You might take possession, or open your practice, on a different day than when your lease commences. Your lease renewal or lease extension notice window deadline follows your lease commencement date, so confirm that exact date and do not assume it matches the others.
What is a floating commencement date?
A floating commencement date is tied to an event that has not happened yet, like the end of your build out or the day the landlord hands over the space. A floating date is often negotiated in your favor, so you do not pay rent on an empty space. The risk is losing track of the date once the event finally happens.
How do I find my commencement date if my lease does not state it plainly?
Ask your landlord for a written notice of commencement while everyone still remembers.
Why does my commencement date matter when I renew or extend my lease?
Your right to renew or extend your lease has to be used inside a notice window before your lease ends. That window is counted back from your end date. Miss the window, and you can lose your space and your healthcare practice.
