A chimney and an offwidth are both wide cracks, defined by whether your body fits inside. A chimney is wide enough to climb inside using full-body counter-pressure; an offwidth is narrower — too wide to hand-jam but too tight to get inside — making it climbing's most awkward, strenuous size.
| Aspect | Chimney | Offwidth |
|---|---|---|
| Width | Fits your whole body | Too wide to jam, too narrow for body |
| Technique | Back-and-foot counter-pressure | Arm bars, chicken-wings, stacking |
| Difficulty | Awkward but can rest | Very strenuous, insecure |
| Protection | Large gear, often sparse | Big cams / Big Bros, hard to place |
| Reputation | Tiring | Feared |
It's a chimney when…
- You can fit your whole body inside
- You press back and feet on opposing walls
- There's room to find a rest
It's an offwidth when…
- It's too wide to hand-jam
- It's too narrow to climb inside
- You're forced into arm bars and stacking
Verdict
Frequently asked questions
What's the difference between a chimney and an offwidth?
A chimney is wide enough to fit your whole body inside and climb with full-body counter-pressure; an offwidth is narrower — too wide to hand-jam but too tight to get inside — making it far more awkward and strenuous.
Why are offwidths so hard?
Because the crack is the wrong size for secure jams, you rely on insecure, energy-sapping techniques like arm bars, chicken-wings, and stacking, while inching upward. They're exhausting, awkward to rest on, and hard to protect.
How do you climb a chimney?
By bracing your back against one wall and your feet against the other so counter-pressure holds you, then 'walking' upward by alternately moving your back and feet. Wider chimneys are more committing; narrower ones blend into offwidth technique.
Related: Chimney · Offwidth · Crack climbing · Jamming