AuscultifyCrackles vs Wheezes: How to Tell Them Apart
Crackles and wheezes are the two adventitious (added) lung sounds students confuse most — and studies show even experienced clinicians agree only moderately when classifying them by ear. The good news: three simple questions separate them almost every time.
The three-question test
| Ask | Crackles | Wheezes |
|---|---|---|
| Continuous or discontinuous? | Discontinuous — separate pops you could count | Continuous — a sustained musical tone |
| When in the breath? | Usually inspiration | Usually expiration (both if severe) |
| What does it sound like? | Popping, clicking — Velcro pulling apart | High-pitched whistle |
What causes each sound
Crackles come from small airways and alveoli popping open against fluid or collapse. Fine crackles (soft, high-pitched, end-inspiratory) suggest interstitial disease or early pulmonary edema and atelectasis; coarse crackles (louder, wetter) suggest pooled secretions, pneumonia or established pulmonary edema.
Wheezes come from air forced through narrowed airways — the walls vibrate like a reed. Diffuse expiratory wheeze points to asthma or COPD; a fixed, localized wheeze can signal an obstruction such as a tumor or foreign body.
Don't confuse these two look-alikes
- Rhonchi — low-pitched, snore-like, from larger-airway secretions; often clears with a cough, unlike crackles.
- Stridor — a loud inspiratory wheeze heard over the neck; an upper-airway emergency, not a lower-airway sound.
Hear the difference in Auscultify
Reading the table won't make you recognize a crackle at 3 a.m. on the ward — your ear has to hear it dozens of times. Auscultify's Lung Sounds mode quizzes you on real recordings of fine and coarse crackles, wheezes, rhonchi and rubs, and its Spectrogram view (Pro) lets you see the discontinuous spikes of a crackle versus the horizontal band of a wheeze — a technique shown to improve classification accuracy.
Practice lung sounds free →How to lock it in
Do a two-minute drill: listen to a crackle, then a wheeze, back to back, and say the discriminator out loud ("discontinuous, inspiratory — crackle"). Alternating comparison is far more effective than listening to one sound in isolation. Ten of these paired reps a day and the distinction becomes reflexive before your respiratory block ends.