Cups to Milliliters Formula Explained

4 min read•June 1, 2025•Reviewed: June 1, 2026

✓Reviewed by Apex Conversion Editorial Team · Last reviewed June 1, 2026

The formula for converting US cups to milliliters is mL = cups × 236.588. One US cup is defined as exactly 236.5882365 mL — a value derived from the US fluid ounce (29.5735 mL) since 1 cup = 8 fl oz. This is a single multiplication with no other steps required.

The critical distinction: a US cup (236.6 mL) differs from a metric cup used in Australia and Canada (250 mL exactly) and an old UK cup (284 mL). If a recipe specifies a cup without saying which system, the country of origin determines which definition applies.

The Formula

mL = cups × 236.588  (US cup)
mL = cups × 250      (metric/AU/CA cup)

Worked examples (US cups):
  ¼ cup × 236.588 =  59.1 mL
  ⅓ cup × 236.588 =  78.9 mL
  ½ cup × 236.588 = 118.3 mL
  ¾ cup × 236.588 = 177.4 mL
  1 cup × 236.588 = 236.6 mL
  2 cups × 236.588 = 473.2 mL
  4 cups × 236.588 = 946.4 mL  (≈ 1 quart)

Quick estimate: multiply by 240 (within 1.4%)
  1 cup × 240 = 240 mL  (exact: 236.6 mL)

US Cup vs. Metric Cup

US cup: 236.5882365 mL (exactly), derived from the US fluid ounce system. Metric cup (Australia, Canada, New Zealand): exactly 250 mL. The difference is about 5.5%. A recipe calling for 1 metric cup that you measure with a US cup measure will be short by about 13.4 mL — significant for baking.

Old UK cup (pre-1970s): approximately 284 mL (based on the British imperial fluid ounce). This is rarely encountered today but appears in older British cookbooks. Always check the publication date and country of origin when following recipes.

Quick Tips

✓
Multiply by 240 for a quick estimate — off by only 1.4% from the exact 236.6.
✓
½ cup ≈ 120 mL — a useful cooking anchor. The exact value is 118.3 mL.
✓
1 cup ≈ 237 mL — round to 240 for quick recipe scaling.
✓
Australian cups = 250 mL; US cups = 236.6 mL — check the recipe's country of origin.
✓
For precision baking, use a liquid measuring cup with mL markings rather than converting.