Key Duplication: What Hardware Stores Can and Cannot Do

Key duplication is one of the simplest locksmith services and one of the most often misunderstood. Most people assume any hardware store can copy any key, and most of the time that's true — but the cases where it isn't are the cases where homeowners get frustrated, get the wrong copy, or end up with keys that don't work. This article explains where hardware stores work, where they don't, and why some keys require a locksmith.

What hardware stores do well

Standard residential keys — house keys, common deadbolt keys, basic padlock keys — duplicate quickly and inexpensively at most hardware stores. The store matches the key blank to your original, traces the cuts, and produces a working copy in a minute or two. Cost is typically two to five dollars per key.

The reason this works is that the keys involved use common blanks (the uncut metal piece) and standard cut depths. The blanks are widely available, the cutting machines are widely available, and the work is mechanical and reliable.

For most everyday house and basic lock needs, the hardware store is the right place.

What hardware stores struggle with

Several categories of keys give hardware stores trouble:

High-security keys. Locks from manufacturers like Medeco, Mul-T-Lock, and similar high-security brands use proprietary keyways that hardware stores typically don't carry. These keys also often include features (sidebar pins, dimples, magnetic elements) that standard cutting machines can't reproduce. Even if the store has the right blank, the cutting may be too imprecise to produce a working key.

Restricted commercial keys. Many commercial master key systems use restricted blanks that require authorization to duplicate. Hardware stores typically can't duplicate these even when asked, because the blanks are only sold through authorized dealers. This is a feature, not a problem — the restriction is what prevents employees from making unauthorized copies.

Older key blanks. Keys from older locks sometimes use blank profiles that aren't manufactured anymore. Hardware stores may have a similar blank but not exact, and the duplicate may not work reliably or at all.

Newer car keys. Modern car keys with transponder chips, smart key fobs, and proximity keys are not duplicated at hardware stores. The mechanical cutting is sometimes possible, but the electronic programming is not. A car key duplicated at a hardware store often turns the lock but doesn't start the engine.

Foreign keys. Keys from imported locks often use blank profiles uncommon in North American hardware stores. The right blank may not be available, or the cutting machine may not be configured for the profile.

Why hardware store copies sometimes don't work

A duplicated key that doesn't work is frustrating, and the reason is usually one of three things:

Wrong blank. The store used a blank that's similar but not identical to the original. Tiny differences in the blank profile prevent the key from entering or turning the lock.

Imprecise cutting. Standard cutting machines have tolerance limits. Each duplication of a duplication adds tolerance error — by the third or fourth generation copy, the accumulated tolerance can exceed what the lock accepts.

Worn original. A worn original key copies poorly. The cutting machine traces the worn cuts and produces a duplicate that matches the worn key — which may work in the worn lock but not in any other lock keyed alike.

The solution to all three is to duplicate from a key in good condition, using the right blank, on a well-maintained machine. A locksmith handles all three; a hardware store does the best they can with what they have.

When to use a locksmith for duplication

Take a key to a locksmith rather than a hardware store when the key is from a high-security or restricted system, the key is for a car (any modern car), the original key is significantly worn, multiple previous copies haven't worked, the key is from an unusual or older lock, you need many copies (a locksmith may charge less per key on volume), or you need the duplication to be precise (for example, for a long-term keyed property).

The cost is somewhat higher — five to fifteen dollars per key for residential, thirty to eighty for car keys depending on type — but the success rate is significantly higher.

Key codes vs duplication

A subtler service offered by locksmiths is "key by code." Rather than copying an existing key, the locksmith cuts a new key from the lock's specifications. This requires either the original code (often stamped on the lock or available from the manufacturer) or impressioning the lock to determine the cuts.

Key by code produces a key that exactly matches the lock's design rather than a copy that matches whatever wear is in the existing key. For long-term keyed properties — businesses, rental properties, vacation homes — this is the right way to maintain keys over years of use.

Restricted key duplication

When a master key system is designed correctly with restricted keyways, key duplication is intentionally limited. The system administrator authorizes duplication; the locksmith verifies authorization before duplicating. This prevents the silent multiplication of keys that otherwise happens.

For restricted systems to actually provide control, the duplication restrictions must be enforced. This means the locksmith requires written authorization for each duplication, a key control log tracks every key issued, and lost keys trigger lock changes for affected doors.

A restricted system that gives keys freely defeats its own purpose.

Car key duplication specifically

Modern car keys deserve specific attention because they're commonly attempted at hardware stores and commonly fail.

Cars from the late 1990s onward use transponder chips. The chip in the key communicates with the vehicle's immobilizer, and the engine won't start unless the chip is properly programmed. Hardware stores can sometimes cut the metal portion of the key but cannot program the chip.

Cars from approximately 2010 onward increasingly use smart key fobs — proximity keys with no metal blade. These have no equivalent in hardware store duplication; they require dealer or specialty automotive locksmith service.

For any car key duplication, a properly equipped automotive locksmith is the right call.

Cost comparison

Approximate pricing:

Hardware store standard key copy: two to five dollars.

Locksmith standard key copy: five to fifteen dollars.

Locksmith high-security key copy: fifteen to fifty dollars.

Locksmith car key (transponder): eighty to two hundred fifty dollars.

Locksmith smart fob: two hundred to six hundred dollars.

Restricted commercial key (locksmith only): ten to thirty dollars.

The hardware store wins on simple cases. The locksmith wins on anything beyond simple — and "beyond simple" is more keys than most people realize.

How many copies you actually need

Most homeowners over-duplicate keys without thinking. Each copy is a security risk if it goes missing, and the risk multiplies with each additional copy. The right number of copies for a typical home is probably fewer than most people make.

A primary key for each adult who lives in the home, a single trusted spare with a neighbor or family member, and a key for any regular service provider who actually needs unattended access. That's usually it. Additional copies "just in case" don't add value and do add risk.

For rental properties, the right number is governed by lease terms and key control practices rather than convenience. For commercial properties, master key systems handle access through design rather than copy proliferation.

When to stop duplicating and start over

Sometimes the right answer isn't another copy — it's rekeying. If the existing keys have been lost, given to too many people, or duplicated too many times to track, rekeying gives you a fresh start with controlled key distribution. The cost of rekeying is modest compared to the security benefit of restored control.

A locksmith can advise on whether duplication or rekeying is appropriate for the situation. The right choice depends on how the keys have been managed up to this point, not just what the immediate need is.