Is Coffee Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1 cup (236 g)
Verdict: 🟢 Safe
Per 100g: 1 mg
Data: Harvard T.H. Chan SPH (2024)
What this means: Coffee is rated Safe (🟢). At 2 mg oxalate per serving, it's well under the 25 mg safety threshold. You can include it regularly in a kidney stone diet. Pair it with calcium-rich foods (dairy, fortified plant milks) for additional protection, and drink plenty of water throughout the day.
Among beverages, Coffee sits well below the category average of 40 mg. For context, 82 out of 92 beverages (89%) are rated 🟢 Safe (under 25 mg oxalate/serving). The average beverages in our database has 40 mg oxalate per serving — which means Coffee is 95% below the category norm. Within its specific category, Coffee ranks among the lower-oxalate options. This context matters because two 'Safe' foods can have very different oxalate levels — one might have 5 mg while another has 24 mg. Both are Safe, but the first gives you more dietary flexibility. Browse all beverages rated Safe to compare within the same verdict level.
Why does the safe threshold matter?
The 25 mg cutoff comes from clinical guidance for stone formers. Below it, a food's oxalate contribution is small enough not to move the needle for most patients. Harvard's 2024 lab data sits behind these figures — direct measurements, not estimates. For Coffee, the measured oxalate value is 2 mg per 1 cup (Safe).
Can I eat this food every day?
If it's in the Safe zone (under 25 mg/serving), yes — it can be a regular part of your diet. For Caution or Avoid foods, frequency matters. Rotate them with lower-oxalate options throughout the week. Applied to Coffee: 2 mg oxalate per 1 cup — Safe per Harvard (2024).
Where does the oxalate data come from?
The numbers come from Harvard T.H. Chan SPH's 2024 laboratory measurements, published through the OHF database. Direct lab analysis, which is why they're treated as the reference values for food oxalate. Applied to Coffee: 2 mg oxalate per 1 cup — Safe per Harvard (2024).
Should I also check sodium and calcium?
Definitely. Oxalate is only part of the story — high sodium raises calcium in urine, and dietary calcium (from food, not pills) binds oxalate in the gut. The food's main page lists both, so it's worth checking before you plan around it. For context, Coffee measures 2 mg per 1 cup, rated Safe.