Quick answer: A keyed padlock is generally more secure and more weather-resistant, because there is no dial or keypad to jam or expose. A combination padlock wins on convenience: nothing to carry, nothing to lose, and you can share the code without cutting keys. Choose keyed for outdoor gates, sheds, and anything exposed to rain or freezing temperatures. Choose combination for gym lockers, shared storage, and low-value indoor use where keys would get lost. Rule of thumb: outdoors → keyed; shared/multi-user → combination. SEPOX combination locks start at $18.99 (55mm resettable); keyed models start at $11.99 (40mm brass).
The core trade-off
Every padlock is a balance between security, convenience, and durability. Combination and keyed locks sit at different points on that triangle:
| Factor | Keyed | Combination |
|---|---|---|
| Security (pick/bypass resistance) | Higher | Lower |
| Convenience for one user | Needs a key | No key to carry |
| Convenience for many users | Re-key or cut copies | Share the code |
| Weather resistance | Better (sealed keyway) | Weaker (dial can freeze/jam) |
| Cost for multiple locks | One key can open all (KA) | Each lock has its own code |
| Forgotten code/key recovery | Cut the lock | Brute-force or cut the lock |
Security: keyed wins, but only slightly
For a determined attacker, both types can be defeated with bolt cutters or an angle grinder — the shackle, not the mechanism, is usually the weak point. Where they differ is against casual bypass:
- Cheap combination locks with a single-dial design can be decoded by feel (tension the shackle, rotate the dial slowly). A 4-digit resettable combination with independent wheels resists this far better.
- Keyed locks with a hardened steel shackle and a pinned cylinder resist picking, but no consumer padlock is pick-proof.
Bottom line: for equal body and shackle, the difference is small. Buy hardened shackle + laminated body first; lock type second.
Weather: the real deciding factor
Outdoor locks live in rain, frost, and dust. Here keyed locks clearly win:
- A combination dial collects water and grit; in freezing conditions the wheels can seize. You may need de-icer and a warm hand to open it.
- A keyed cylinder with a sealed cover (a weatherproof cover plate) keeps moisture out of the mechanism. Our waterproof keyed models use exactly this design.
If your lock faces permanent outdoor exposure, choose keyed with a weatherproof cover. If it only faces occasional damp (a garage interior), a combination lock is fine.
Convenience: combination wins for shared access
The strongest argument for combination locks is shared access without key management:
- A gym locker that a member uses three times a week: no key to lose, code is memorized.
- A rental storage unit: the tenant sets their own code; you never hand over a key.
- A construction site toolbox shared by a rotating crew: text the code, no key cutting.
With keyed locks, sharing access means duplicating keys (a cost and a security leak) or picking a keyed-alike set so one key opens all.
Cost over time
| Scenario | Keyed | Combination |
|---|---|---|
| 1 lock, 1 user | Cheapest | Slightly higher |
| 5 locks, 1 user | Keyed-alike set, one key | 5 different codes to manage |
| 5 locks, 5 users | 5 keys (or one KA key everyone shares) | 5 user-set codes |
For many locks on one property, a keyed-alike set is usually the most economical and convenient: one key, all locks, no codes to remember.
SEPOX picks by use case
| Use case | Recommended | Why |
|---|---|---|
| Outdoor gate / shed | Keyed, weatherproof cover ($12.99–$14.97) | Sealed cylinder survives rain |
| Gym / school locker | 4-digit resettable combination ($18.99) | No key to lose, code is portable |
| Bike / cable lock | Combination cable lock, 7" ($20.98) | Long flexible shackle, no key |
| Multi-lock property | Keyed-alike 2-3/8" set, 2–20 pack ($14.97+) | One key opens all |
| High-value container | Keyed, hardened steel, laminated body | Maximum bypass resistance |
Common buying mistakes
- Buying a combination lock for a coastal or freezing location. The dial will seize. Choose keyed with a cover instead.
- Buying a keyed lock for a gym locker. The key gets lost, and the gym cuts the lock. Combination is the norm there for a reason.
- Judging security by lock type. A cheap keyed lock is weaker than a good combination lock. Body and shackle matter more than the mechanism.
- Ignoring the shackle length. A strong lock that does not fit the hasp is useless. Measure the clearance before ordering.
- Sharing one keyed lock among many users without a keyed-alike set. You end up cutting copies or losing track of who holds a key.
A simple decision checklist
- Is it outdoors year-round? → keyed (weather beats convenience).
- Will several people need access? → combination (share the code).
- Is it high-value or theft-prone? → keyed with hardened shackle.
- Do you hate carrying keys? → combination resettable.
- Multiple locks, one owner? → keyed-alike set.
If two rules conflict, security and weather usually beat convenience for anything outdoors.