Lost All Your Car Keys? Here Is Exactly What Happens Next (San Francisco, 2026)
TL;DR - Quick Answer
If you've lost every key to your car, a qualified mobile automotive locksmith can usually create a brand-new working key at your vehicle — no tow required — by verifying your ownership and then originating a key from scratch, either by decoding the lock or reading the vehicle's key data. This "all keys lost" situation takes longer and costs more than cutting a spare from an existing key, because there's no working key or chip to copy from. Expect the locksmith to ask for proof of ownership before starting, and expect a phone conversation about realistic timing rather than a promised arrival window. The exact cost and process depend heavily on your vehicle's year, make, and key technology.
Why 'all keys lost' is different from a spare copy
Losing your only set of car keys is a different problem than losing one key out of two. When you still have a working key, a locksmith (or dealer) can usually clone or program a duplicate quickly, because the vehicle's security system already recognizes that key's electronic signature. There's a template to copy from.
When all keys are lost, that shortcut disappears. There is no working key to read, no chip to duplicate, and often no way to simply "cut a blank" and drive off. Modern vehicles pair a physical key cut with an embedded transponder chip or remote signal that the car's immobilizer system must recognize before the engine will even start. Without any surviving key, a locksmith has to reconstruct both sides of that equation: the correct physical cut for the door and ignition lock, and a new electronic credential the car's computer will accept.
This is why "all keys lost" (sometimes shortened to AKL in the trade) is treated as its own category of job. It generally requires:
- Decoding the lock cylinder (by disassembly or by lock-picking-style reading) to determine the correct key cut, since there's no key left to trace or measure from
- Connecting to the vehicle's onboard diagnostics port with programming equipment to write a new key or fob into the car's immobilizer memory
- In many newer vehicles, additional security steps such as timed relearn procedures, pin code retrieval, or all-keys-lost specific programming sequences that some vehicles require before accepting any new key
On older vehicles with simple metal keys and no transponder, the job can be much simpler — sometimes just an on-the-spot lock decode and key cut. On newer vehicles with proximity fobs, push-button start, or extra layers of anti-theft security, the process takes longer and typically costs more. The single biggest factor in "how hard is this going to be" is the year and trim of your specific vehicle, not the brand alone.
Proof of ownership: what you must show
Because originating a new key for a vehicle is functionally the same capability someone would need to steal it, reputable locksmiths verify ownership before doing any work. This isn't optional paperwork — it's a basic safeguard for you and for the locksmith.
Typically, you'll be asked for some combination of:
- Government-issued photo ID that matches the name on the vehicle's registration or title
- Vehicle registration or title showing you as the registered owner, or a lease/loan agreement if the vehicle is financed
- If you're not the registered owner (for example, it's a family member's car, a company vehicle, or a rental), documentation showing your authorization to have work done — this varies by situation, so it's worth mentioning your circumstance when you first call
If your registration is also gone or was in the car (a common problem after a break-in or when a purse or bag with everything in it goes missing), a locksmith may accept alternate proof, such as an insurance card with your name and the VIN, but this is handled case by case. Be upfront on the phone about what documents you do and don't have — it helps the locksmith tell you honestly whether they can proceed and what else might be needed, rather than arriving and discovering a documentation gap.
Expect this verification step every time, regardless of how stressed or rushed the situation feels. It's a sign of a locksmith doing the job correctly, not an inconvenience.
How a locksmith originates a key with no working key
Once ownership is confirmed, the actual key-origination work generally follows one of a few paths, depending on the vehicle:
Older vehicles (typically pre-transponder era): A locksmith can often decode the door or trunk lock directly — either by carefully disassembling the cylinder to read the wafer or pin cuts, or by using lock-decoding tools — and then cut a new mechanical key to match. If there's no chip involved, that new cut key may be all that's needed.
Transponder-key vehicles: After determining the correct mechanical cut, the locksmith uses automotive key programming equipment connected to the car's diagnostic port to write new transponder data into the vehicle's immobilizer system, effectively teaching the car to recognize a brand-new key while erasing the electronic identity of any old, lost keys (an important security side benefit — see below).
Proximity/smart-key vehicles: These often require the fob to be programmed to the vehicle's body control module rather than just the ignition, and some manufacturers require all-keys-lost specific procedures, sometimes involving a security PIN tied to the vehicle that a locksmith retrieves through their equipment or, on some makes, through the manufacturer.
Because the mobile locksmith brings this equipment to your vehicle, this work usually happens in a driveway, parking garage, workplace lot, or roadside — wherever the car is parked — rather than requiring a tow to a shop. The mobile setup is one of the main practical advantages in an all-keys-lost situation: the car generally doesn't need to move until it already has a working key again.
One important side effect worth knowing: on most transponder and smart-key vehicles, programming a new key as part of an all-keys-lost job erases the old lost keys from the car's memory. If your keys were stolen rather than simply misplaced, this is a meaningful security step, since it means whoever has your old keys can no longer start the car with them.
Timeline and what affects it
There is no universal number of minutes or hours that applies to every vehicle, and any locksmith who promises an exact turnaround before seeing your car is guessing. What can be said honestly is what tends to make a job faster or slower:
Tends to speed things up:
- An older vehicle with a simple mechanical key and no transponder
- A common, high-volume vehicle model where the locksmith is likely to already carry the correct key blank
- Clear, ready proof of ownership so there's no delay verifying you
- A vehicle that's easy to access (not in a locked garage the locksmith can't reach, not blocked in)
Tends to slow things down:
- Late-model vehicles with proximity/smart-key systems or extra anti-theft layers
- Less common makes or trims where the correct blank or fob isn't something typically carried and may need to be sourced
- Vehicles requiring a manufacturer-specific security PIN retrieval process
- Difficult access, poor weather, or a location that's hard to reach
Because of this variability, the honest answer to "how long will it take" and "when can someone get here" is always confirmed by phone once the locksmith knows your vehicle's year, make, and model — not promised in advance. If timing matters for your day (a flight, a work shift, a school pickup), say so on the call; it helps the locksmith communicate realistically rather than you assuming a number that wasn't guaranteed. No arrival time or completion time should ever be treated as a guarantee, and a locksmith who refuses to give you one hasn't failed to answer your question — they're being accurate.
Cost factors (broad ranges)
Pricing for an all-keys-lost job is genuinely one of the widest ranges in automotive locksmithing, because the two ends of the spectrum involve almost entirely different work. As a broad orientation only — not a quote, and not something to hold any locksmith to before they've seen your vehicle — typical factors that move price up or down include:
- Key technology: A basic mechanical key for an older car sits at the lower end. A proximity smart key or a key requiring dealer-level security PIN retrieval sits at the higher end.
- Number of keys made: Cutting and programming one key costs less than two, though see the section below on why a single key is often a false economy.
- Parts required: The key blank or fob itself is a real, separate cost from labor — some fobs are inexpensive, others (particularly OEM smart fobs for certain makes) are not.
- Lock decoding complexity: A door lock that's easy to decode is faster and cheaper than a worn, damaged, or unusually configured cylinder.
- Mobile service factors: Time of day and distance can be part of a mobile locksmith's pricing structure, similar to any mobile trade.
Because these variables compound, an all-keys-lost job on an older economy car with a basic key can be meaningfully cheaper than the same situation on a newer vehicle with a smart key system — potentially by a wide margin. Any specific figure should come from the locksmith directly, once they know your vehicle's year, make, model, and key type, and it's reasonable to ask for that figure before work begins.
Should you get two keys made?
When you're in an all-keys-lost situation, it's worth thinking one step ahead: do you want the locksmith to cut and program just one key, or two?
The case for getting a second key made at the same visit: the locksmith is already at your car, already has the diagnostic equipment connected, and has already done the harder, more time-consuming part of the job (the lock decode and/or the initial programming setup). Adding a second key at that point is often a smaller incremental step than starting the whole process over on a separate visit later — because a second visit for a lost/forgotten spare would, again, require re-verifying ownership and, depending on the vehicle, could involve owner-arranged pickup and setup all over again.
The case for just getting one key now: cost. If money is tight in the moment, one working key gets you back on the road, and a spare can be made later from that new key using the more standard (and usually less expensive) duplicate-from-existing-key process.
There's no universally "right" answer — it depends on your budget, how soon you expect to want a spare anyway, and whether you'd rather absorb a modest additional cost now versus a separate service call later. It's a reasonable question to raise with the locksmith on the phone before they arrive, since they can walk through what it would mean for your specific vehicle.
Preventing a repeat
Losing every key to a car is often less about carelessness and more about circumstance — a bag or coat stolen, a set left in a rental, a fumble near water, a move between homes. A few habits reduce the odds of it happening again or make the next time far less disruptive:
- Keep a documented spare somewhere other than "with the other keys." A spare at a trusted family member's home, at a workplace, or in a home safe is only useful if it isn't in the same bag, car, or drawer as your primary key.
- Photograph your registration and keep a digital copy. Having a clear photo of your registration (and, if financed, your loan agreement) on your phone or in cloud storage speeds up the ownership-verification step significantly if the original document is part of what's lost.
- Note your VIN somewhere separate from the car. It's printed on your registration and often on your insurance card, but having it saved separately means you're not stuck if both are missing.
- Consider what a second key actually costs you now versus later. If you've never had a spare cut, doing so during ordinary circumstances — not as an emergency — is almost always simpler and less costly than any all-keys-lost scenario.
None of this eliminates the possibility of losing everything at once, but it shortens the recovery when it happens, and in many cases turns a full all-keys-lost job into a much simpler duplicate-key visit instead.
Auto Locksmith San Francisco is a registered trademark (U.S. Reg. No. 5,682,454) and operates under California Locksmith License LCO 6720, bonded and insured. You can verify any locksmith's license with the California Bureau of Security and Investigative Services.
FAQ
I lost both my car keys — can someone actually make me a new one without a spare?
Yes. A qualified mobile automotive locksmith can originate a new key for most vehicles even with no working key or spare remaining, by decoding the lock and/or programming a new key directly into the car's onboard computer. The process and difficulty depend heavily on your vehicle's year and key technology, so it helps to describe your car in detail when you call.
Do I need my registration if I lost my car keys and the registration too?
A locksmith will still ask for proof of ownership, but if your registration is unavailable they may accept other documentation, such as an insurance card showing your name and VIN, evaluated case by case. Call and explain exactly what documents you do have so they can tell you honestly what will work.
Will the locksmith need to tow my car to replace all lost keys?
Usually not. Mobile locksmiths bring lock-decoding and key-programming equipment to wherever your vehicle is parked, so in most all-keys-lost situations the car doesn't need to move until it already has a working key.
How much does it cost to replace all lost car keys in San Francisco?
Cost varies widely because it depends on your vehicle's key technology, whether it's a basic mechanical key or a programmed smart key/fob, and how many keys you want made. Only think of published figures as broad orientation — ask the locksmith for a figure based on your specific vehicle before work begins.
How long will it take to get a new key made if I lost all of them?
There's no fixed timeline that applies to every vehicle; older cars with simple keys are typically quicker, while newer smart-key vehicles or less common models can take longer. Timing is always confirmed by phone once the locksmith knows your vehicle's year, make, and model — not promised in advance.
If my keys were stolen, does making a new key stop the old ones from working?
On most vehicles with transponder chips or smart keys, programming a new key as part of an all-keys-lost job erases the old, lost keys from the car's memory, so they can no longer start the vehicle. This is one of the practical security benefits of the process, not just a convenience.
Should I ask for one new key or two when I've lost them all?
Since the locksmith is already at your vehicle with equipment connected, adding a second key at the same visit is often a smaller incremental step than a separate future visit. Whether it's worth the added cost right now depends on your budget and how soon you'd want a spare anyway — it's worth discussing on the initial call.
What's the difference between losing one key and losing all my car keys?
Losing one key out of a set usually means a locksmith can clone or program a duplicate from the remaining working key, which is faster and generally less expensive. Losing all keys means there's nothing to copy from, so the locksmith must decode the lock and originate a new key and electronic credential from scratch.
Last updated: August 2026.