Short answer: if you live in a flat and want a lock that's small to store and easy to take on every errand, look at a light D-lock with a frame mount. The Pitbull STD 8003 (Diamond, 1.44kg) and Evolution Mini-7 (Gold, 1.61kg) clip on the bike. The Mason 140 is the lightest at about 0.97kg but has no mount in the box. The Bordo 6500K folding lock is heavier, and it's the one for awkward stands.
Worth knowing if you searched for a wearable lock: none of the locks reviewed here is designed to be worn on the body. The ones below are the lightest and most compact of the thirteen, and three of them clip to the frame so they don't take up space in your bag or your hallway.
Compact locks by situation
If you want Diamond in the smallest carry
OnGuard · D-lock
OnGuard Pitbull STD 8003
Diamond (ordinary bikes)
The Pitbull STD 8003 is Sold Secure Diamond and weighs 1.44kg, with a frame mount. Its 115 × 230 mm locking area gives you more room round a stand than most compact D-locks.
1.44kg · 115×230 mm · 14 mm
If Gold is enough and you're popping out a lot
Kryptonite · D-lock
Kryptonite Evolution Mini-7
Sold Secure Gold
The Evolution Mini-7 is Sold Secure Gold at 1.61kg. It has a frame mount and comes with a cable for the front wheel, so it suits short shop and café stops.
1.61kg · 83×178 mm · 13 mm
If weight and storage space matter most
Seatylock · D-lock
Seatylock Mason 140
Diamond (ordinary bikes)
The Mason 140 is about 0.97kg and Sold Secure Diamond for ordinary bikes. It's the lightest lock here and small enough for a bag or a hallway hook.
0.97kg · 140×85 mm
If your stands are awkward
ABUS · Folding
ABUS Bordo 6500K
Sold Secure Gold
The Bordo Granit 6500K folds into a block on its SH bracket and opens to 120 cm. It's Sold Secure Gold.
2.47kg · 120 cm · 5.5 mm
What makes a lock good for a flat
If you keep the bike in a hallway or a small store, the lock has to live somewhere too. A lock that clips to the frame stays with the bike, so it doesn't end up on a shelf or in a drawer when you're heading out.
Weight matters more than it seems when you're making several short trips a day. At under 2kg you're more likely to take the lock every time, and that's the point of owning one.
If you're locking the bike in a shared bike store or a block-of-flats car park, check what you can lock to. A compact D-lock needs a stand or anchor it can close round. For reach at home, a chain is the better tool, and D-lock vs chain explains why many people own both.
If you ride for delivery work
The same picks apply, with one difference: you lock up many times a shift, so the frame mount matters. The Pitbull STD and Mini-7 both clip on. We'd check your stops have Sheffield stands before relying on a narrow shackle, and see bike locks for delivery riders and e-bikes for e-bike grades and quick-access picks.
Common questions
What's the best compact lock for frequent errands?
If you want a frame mount and a cable for the wheel, the Evolution Mini-7 (Gold, 1.61kg) suits short stops. If you'd rather have Diamond, the Pitbull STD 8003 is 1.44kg with a mount.
Are there wearable bike locks in this list?
No. None of the locks reviewed on Lock Desk is designed to be worn. The lightest is the Mason 140 at about 0.97kg, which fits in a bag.
What's the lightest Diamond lock here?
The Mason 140 at about 0.97kg, though its mount is sold separately. The Pitbull STD 8003 is 1.44kg and comes with a frame mount.
How to choose a bike lock · Best of · Reviews · D-lock vs chain · How we research