I need a smart lock that works with my existing deadbolt hardware.

Yes — you want a retrofit smart lock, which mounts on the inside of your existing deadbolt rather than replacing the whole deadbolt. Your exterior hardware and physical key can stay unchanged.

Here are the strongest options right now:

• SwitchBot Lock Pro - $89.99 (SwitchBot)

• August Wi-Fi Smart Lock - $199.99 (August Home + others)

• Aqara Smart Lock U100 - $186.99 (Aqara + others)

• Level Bolt (Matter) - $199.00 (Level Home + others)

• SwitchBot Lock Pro — best overall for compatibility. It fits a particularly broad range of existing deadbolts and is a good choice if you want Matter/smart-home integration. Remote access requires a SwitchBot hub.

• August Wi-Fi Smart Lock — simplest option. It mounts over the existing deadbolt, keeps your key, and has Wi-Fi built in, so you don't need a separate hub.

• Aqara U100 — best if you use Apple Home. It adds fingerprint entry and Apple Home Key, but compatibility with your particular deadbolt needs to be checked carefully.

• Level Bolt — best if you want it invisible. The smart components go inside the door/bolt mechanism, leaving the exterior looking essentially unchanged.

One important check: retrofit locks aren't universally compatible. Your existing deadbolt needs to have the right type of interior thumbturn, and the bolt should operate smoothly by hand. A stiff or misaligned deadbolt can cause problems for any motorized retrofit lock.

If you tell me the brand/model of your current deadbolt (or send me a photo of the inside and outside), I can narrow this down to the locks that should actually fit.

You need a retrofit smart lock that mounts to the inside of your door while leaving your exterior keyhole and deadbolt hardware completely unchanged.

Watch this video to see an overview of how a retrofit smart lock preserves your existing exterior deadbolt hardware while adding smart capabilities:

Top Retrofit Smart Lock Options

Attaches to your existing thumbturn on the interior side of the door, letting you use your original keys outside while offering auto-lock, app control, and voice assistant integration.

Installs completely inside your door mechanism (replacing the standard deadbolt core), making it completely invisible from the outside and preserving 100% of your current exterior faceplate and hardware look.

Offers various interior conversion options or full replacements that match standard cylindrical setups while keeping aesthetic consistency.

Comparison of Popular Retrofit Styles

If you can tell me which smart home ecosystem you use (Apple Home, Amazon Alexa, or Google Home) and whether you want to keep your exterior keys visible , I can recommend the exact model that fits your setup.

Yes — you want a retrofit smart lock, which mounts on the inside of your existing deadbolt rather than replacing the whole deadbolt. Your existing key and exterior hardware can stay intact.

• SwitchBot Lock Pro - $119.99 (Best Buy)
• August Wi-Fi Smart Lock - $199.99 (The Home Depot)
• Yale Approach Retrofit Smart Lock - $140.99 (Wayfair)
• Level Bolt (Matter) - $199.00 (The Home Depot)

My picks

• SwitchBot Lock Pro — best overall retrofit. Broad deadbolt compatibility, rechargeable battery, and Matter support when paired with its hub.
• August Wi-Fi Smart Lock — simplest choice. It attaches to the inside of your existing deadbolt, keeps your keys working, and has Wi-Fi built in, so you don't need a separate hub.
• Yale Approach — a newer retrofit option from Yale; it preserves the existing deadbolt and can be paired with a keypad if you want PIN entry.
• Level Bolt (Matter) — best if you want the lock to be nearly invisible. The electronics go inside the door/bolt mechanism, so the exterior remains essentially unchanged.

Important: retrofit compatibility depends on the exact deadbolt, especially the shape of the inside thumb-turn and the available clearance. Also, your deadbolt should operate smoothly by hand; a stiff or misaligned bolt can cause problems for any retrofit motor.

If you tell me the brand/model of your current deadbolt (or send me a photo of the inside and outside), I can narrow this down to the best compatible lock for you.

If you want to keep your exterior deadbolt hardware and your physical keys, you need a retrofit smart lock . These replace only the interior thumb-turn mechanism of your existing single-cylinder deadbolt , leaving the outside of your door looking completely normal.[1]

The best options on the market depend on how hidden you want the lock to be and what smart home ecosystem you use:

Add to list The most popular and well-tested choice. It replaces just the inside thumb-turn, installs in about 10 minutes with a screwdriver, has built-in Wi-Fi (no separate bridge required for remote access), and lets your original exterior key work seamlessly.

Add to list Yale’s dedicated retrofit lock attaches right over your existing single-cylinder deadbolt interior. It features a sleek, compact profile and uses the Yale Access app. You can also buy it bundled with a wireless keypad if you want code entry on the outside.[1]

Add to list The ultimate "invisible" upgrade . Instead of mounting a device over your thumb-turn on the inside, the Level Bolt replaces the actual internal bolt mechanism inside the door. Your existing interior thumb-turn and exterior keyhole look and act 100% normal, but the lock gains smart capabilities (via Matter-over-Thread).[1]

Add to list A robust, universal rear-mounted retrofit lock that fits over a wide variety of US and international deadbolts. It's strong, supports quick-install magnetic sensors, and offers modular connectivity options (Matter/Wi-Fi).

To help narrow down the best fit for your door, let me know:

• Do you prefer an interior-mounted device (like August/Yale) or a completely invisible internal install (like Level Bolt)?
• What smart home ecosystem do you use most (Apple Home, Google Home, Amazon Alexa)?
• Do you need a physical keypad outside for guest codes, or just use your phone/app?

If you want to keep your existing deadbolt and exterior keys, you need a retrofit smart lock . These install entirely on the interior side of your door—replacing just your current thumb turn—while leaving the outside hardware and your physical keys completely unchanged.[1]

Top options that work with your existing deadbolt hardware include:

Add to list The gold standard for retrofitting. It fits over most standard single-cylinder deadbolts, has built-in Wi-Fi (so no bulky separate bridge is required), and supports auto-unlock as you approach. Note: It doesn't have a built-in keypad, though you can buy an optional August Smart Keypad.

Add to list Yale’s dedicated interior-only retrofit lock. It swaps out your inside thumb turn for a sleek motorized unit, works with your existing single-cylinder deadbolt, and connects via the Yale Access app (bundled with a Wi-Fi connection kit). You can also add an optional matching wireless keypad.[1]

Add to list A versatile, heavy-duty retrofit choice that attaches with strong adhesive or a secure mechanical fit over your thumb turn. It supports Matter (via an add-on hub) for broad smart home integration, offers quick installation, and features a modular battery bay.[1]

To help narrow down the best choice for your setup , let me know:

• What brand of deadbolt do you currently have (e.g., Schlage, Kwikset)?
• Do you prefer an exterior keypad for PIN entry, or just your smartphone/auto-unlock?
• What smart home ecosystem do you use (Apple Home, Google Home, or Amazon Alexa)?

Yes — you want a retrofit smart lock, which mounts on the inside of your existing deadbolt rather than replacing the whole lock. Your existing key and exterior hardware can remain unchanged.

My top picks

• SwitchBot Lock Pro - $119.99 (Best Buy)

• August Wi-Fi Smart Lock - $199.99 (The Home Depot)

• Yale Approach Retrofit Smart Lock - $89.99 (Best Buy)

• Level Bolt Matter - $199.00 (The Home Depot)

• SwitchBot Lock Pro — best overall/value. It mounts over the interior thumbturn, retains your existing key, and has particularly broad deadbolt compatibility. Matter support is available with the appropriate hub.

• August Wi-Fi Smart Lock — best if you want simplicity. It fits over the existing deadbolt and has Wi-Fi built in, so you don't need a separate hub for remote access.

• Yale Approach — good alternative. It's Yale's newer retrofit design and can be paired with a keypad if you want code or fingerprint entry.

• Level Bolt — best if you want it nearly invisible. The electronics are installed inside the door, preserving the appearance of your existing hardware.

One important catch: compatibility depends on the exact deadbolt. Retrofit locks generally work with single-cylinder deadbolts with an interior thumbturn, but unusual thumbturn shapes, mortise locks, multi-point locks, or very tight clearances can be problematic.

If you tell me (1) the brand/model of your current deadbolt or send me a photo of the inside of the door, and (2) whether you use Apple Home, Google Home, or Alexa, I can narrow this down to the best exact lock for your door.

Yes — you want a retrofit smart lock, which mounts on the inside of your existing deadbolt rather than replacing the whole lock. That means your exterior hardware and physical key can stay unchanged.

My top choices

• August Wi-Fi Smart Lock - $199.99 (The Home Depot)

• SwitchBot Lock Pro - $119.99 (Best Buy)

• Yale Approach Retrofit Smart Lock - $88.75 (The Home Depot)

• Level Bolt (Matter) - $199.00 (The Home Depot)

• Best simple choice: August Wi-Fi Smart Lock — mounts over the existing interior thumb-turn, keeps your key, and has Wi-Fi built in, so you don't need a separate hub. It's the option I'd choose if you want phone control with minimal fuss.

• Best value/flexibility: SwitchBot Lock Pro — another interior retrofit that preserves your existing deadbolt. It has particularly broad deadbolt compatibility and can use Matter through a SwitchBot hub.

• Best if you want keypad/fingerprint access: Yale Approach — it's also a retrofit, and Yale offers versions with Wi-Fi and a keypad/fingerprint reader.

• Best if you want the lock to be almost invisible: Level Bolt — the mechanism installs inside the door rather than sitting prominently over the thumb-turn.

One important caveat: retrofit locks need your existing deadbolt to operate smoothly. If you currently have to push/pull the door while turning the deadbolt, fix that alignment issue first; the motor can struggle with a stiff bolt.

If you tell me (1) the brand/model of your current deadbolt, (2) whether you use iPhone/Android, and (3) whether you want a keypad, I can narrow this down to the best exact model for your door.

If you want to keep your exterior keyhole and hardware intact (great for renters or matching unique door aesthetics), you need a retrofit smart lock . These install exclusively on the inside of your door by replacing your existing thumb-turn mechanism, leaving the outside completely unchanged.

Top options that work with your existing deadbolt hardware include:

Add to list The classic choice that mounts over your existing single-cylinder deadbolt interior. It lets you keep your original keys on the outside while adding auto-unlock, app control, and smart home integration [2].

Add to list A slimmer, modern profile (about 25% smaller than August) that swaps out just your interior escutcheon and thumb turn, allowing you to retain your exterior deadbolt and key [578711, shopyalehome.com].

Add to list Highly versatile and fits over a wide variety of standard deadbolts and latches without needing to drill or change your keys [SwitchBot Lock Pro Smart Door Lock]. It supports a wide array of smart home ecosystems [SwitchBot Lock Pro Smart Door Lock].

Add to list The ultimate "invisible" retrofit option. Instead of mounting a bulky unit on the inside of the door, the Level Bolt actually replaces the inside core and bolt mechanism of your existing deadbolt while letting you keep your original visible interior and exterior trim.

If you'd like to narrow this down, tell me:

• Do you care about having a physical keypad on the outside?
• What smart home ecosystem do you use (Apple Home, Alexa, or Google Home)?

Yes — you want a retrofit smart lock, which mounts on the inside of your existing deadbolt rather than replacing the whole deadbolt. Your existing key and exterior hardware can stay unchanged.

Here are the ones I'd consider:

• August Wi-Fi Smart Lock - $199.99 (The Home Depot)

• SwitchBot Lock Pro - $119.99 (Best Buy)

• Yale Approach Retrofit Smart Lock - $140.99 (Wayfair)

• Level Bolt (Matter) - $199.00 (The Home Depot)

• August Wi-Fi Smart Lock — My safest all-around recommendation. It fits over the inside of your existing deadbolt, keeps your physical keys working, and has Wi-Fi built in, so you don't need a separate hub.

• SwitchBot Lock Pro — Best if you're worried about compatibility. Its adjustable mounting system supports a particularly broad range of existing deadbolts; Matter support is available with the Hub Mini.

• Yale Approach — A good alternative if you want to stay in the Yale/​August ecosystem, with optional keypad/fingerprint accessories. It also installs on the inside of the existing deadbolt.

• Level Bolt (Matter) — Best if you want the smart-lock hardware essentially invisible. Instead of adding a large mechanism over the thumbturn, it installs inside the door and preserves the existing exterior hardware.

The important part: compatibility depends on your exact deadbolt — especially whether it's a single-cylinder deadbolt, the thumbturn shape, and the door/lock dimensions.

If you tell me the brand/model of your current deadbolt (or send me a photo of the inside and outside of the lock), I can narrow this down to the best 1–2 locks that will actually fit, including current prices.

The Yale Approach Smart Deadbolt Go to product viewer dialog for this item. and SwitchBot Lock Pro Go to product viewer dialog for this item. attach to your existing interior deadbolt hardware so you can keep your current exterior keys.[1][2]

Top Retrofit Smart Locks

Popular Options

Add to list Installs on the inside of your door while leaving the outside hardware completely untouched.[1]

Add to list Universally adapts to most standard US deadbolts with an easy rear-mounted magnetic/adhesive or screw setup.[1]

Add to list Replaces just the interior thumbturn of most standard single-cylinder deadbolts with a compact round design.[1]

If you'd like, tell me:

• What brand of deadbolt do you currently have?
• Do you need Wi-Fi remote access or just Bluetooth/auto-unlock?

I can help you pick the exact model that fits your setup.