A standard 12 oz (355 ml) can of Coke Zero has about 34 mg of caffeine in the US, which is roughly one‑third of a typical cup of coffee.

Quick Scoop: Caffeine in Coke Zero

  • 12 oz (355 ml) Coke Zero: about 34 mg caffeine.
  • This is similar to regular Coca‑Cola, which also has about 34 mg per 12 oz.
  • It is clearly not caffeine‑free; there is a separate “Caffeine Free Coke Zero” version if you want zero caffeine.

How that compares to other drinks

  • Regular coffee (8 oz): about 80–100 mg caffeine.
  • Espresso (1 shot): around 60–64 mg.
  • Green tea (8 oz): roughly 25–50 mg.
  • Diet Coke (12 oz): about 46 mg, so noticeably more than Coke Zero.

Here’s a simple HTML table you can reuse:

html

<table>
  <thead>
    <tr>
      <th>Beverage</th>
      <th>Serving size</th>
      <th>Approx. caffeine</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Coke Zero</td>
      <td>12 oz (355 ml)</td>
      <td>34 mg</td>
    </tr>
    <tr>
      <td>Regular Coca-Cola</td>
      <td>12 oz (355 ml)</td>
      <td>34 mg</td>
    </tr>
    <tr>
      <td>Diet Coke</td>
      <td>12 oz (355 ml)</td>
      <td>46 mg</td>
    </tr>
    <tr>
      <td>Green tea</td>
      <td>8 oz (237 ml)</td>
      <td>25–50 mg</td>
    </tr>
    <tr>
      <td>Black coffee</td>
      <td>8 oz (237 ml)</td>
      <td>80–100 mg</td>
    </tr>
  </tbody>
</table>

A quick perspective

If you’re tracking intake, many health authorities consider up to about 400 mg of caffeine per day acceptable for most healthy adults, which would be around 10–11 cans of Coke Zero, but only about 4–5 cups of coffee. Sensitivity varies a lot, though, so some people may feel effects at much lower amounts.

Always double‑check your local can or bottle: labels can vary slightly by region and formulation, but they typically still show around the mid‑30 mg range for a 12 oz Coke Zero.

TL;DR: Coke Zero is low in caffeine compared to coffee but definitely not zero; plan for roughly 34 mg per 12 oz can.

Information gathered from public forums or data available on the internet and portrayed here.