Does decaf have caffeine?

The short answer: about 2–5 mg per cup

A typical 8 oz cup of decaf coffee contains roughly 2–5 mg of caffeine — compared with about 95 mg in regular coffee. So decaf has around 95–97% less, but it's not caffeine-free. See it next to every other drink on the caffeine chart. (Values are typical averages; the exact amount varies by bean, roast and method.)

Why isn't it zero?

Decaffeination strips out about 97% of the caffeine, but removing the last few percent without ruining the flavour isn't worth it. By law in many countries, coffee can be sold as "decaffeinated" once it's at least 97% caffeine-free — so a trace always remains.

Does it matter?

• For sleep: for almost everyone, 2–5 mg is too little to matter — decaf is a genuinely good evening swap. The exception is several cups late at night, or extreme sensitivity.
• If you're pregnant: decaf's trace amount is comfortably within the under-200 mg/day guideline, even across several cups.
• If you drink a lot of it: ten decafs is ~20–50 mg — still well under any limit, but worth knowing.

Decaf vs half-caf vs regular

If you're cutting down rather than cutting out, decaf is the floor and half-caf (~45 mg) is the middle step. Tapering through them is the gentlest way to quit without the withdrawal headache.

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Put it into practice: swapping to decaf after a cutoff time? Check what's still in you at bedtime with the half-life calculator.