Standard Styrofoam Cups Hold 8-12 oz (236-355 ml)

A typical Styrofoam cup holds 8 to 12 US fluid ounces, equivalent to 236-355 milliliters (ml). Sizes vary: small (8 oz/236 ml), medium (10 oz/296 ml), and large (12 oz/355 ml). Always check the cup's marked capacity for precision, as disposable cups lack universal standardization.

Common Styrofoam Cup Sizes (Ounces to Milliliters)

• 6 oz cup: ~177 ml (rare, often for sample servings)
• 8 oz cup: ~236 ml (standard small size)
• 10 oz cup: ~296 ml (medium, common for coffee)
• 12 oz cup: ~355 ml (large, typical for sodas)
• 16 oz cup: ~473 ml (extra-large, less common)

How to Measure Without Markings

1. Use a kitchen scale: Weigh water in grams (1g = 1ml) poured into the cup.
2. Compare to a measured vessel: Fill a known-measurement cup (e.g., 250ml) and transfer to the Styrofoam cup.
3. Estimate by height: A standard 8 oz cup is ~3.5 inches (8.9 cm) tall; 12 oz is ~4.5 inches (11.4 cm).

Volume Comparison: Styrofoam vs. Reusable Cups

Factors Affecting Actual Capacity

• Rim design: Cups with rolled rims may hold slightly less than marked.
• Temperature: Hot liquids expand marginally (negligible for most uses).
• Manufacturer variance: Budget cups may deviate by ±5% from labeled size.
• Lid addition: Adding a lid reduces usable volume by ~5-10 ml.

Quick Conversion Cheat Sheet