The Short Answer
There is no single answer. 1 cup of water = 236.59g, but 1 cup of flour = 125g and 1 cup of honey = 340g. The difference is density — how much an ingredient weighs per unit of volume.
grams = cups × density (g/cup)
Where density varies by ingredient: flour ≈ 125 g/cup, sugar ≈ 200 g/cup, butter ≈ 227 g/cup
Why Does It Vary So Much?
Imagine filling a cup with feathers versus filling it with sand. Same cup, very different weights. The same principle applies to cooking ingredients:
- Flour (125g/cup) — light, airy, traps air between particles
- Sugar (200g/cup) — denser crystals, packs tighter
- Honey (340g/cup) — thick liquid, much heavier than water
- Cocoa powder (86g/cup) — very light and powdery
The Measurement Method Problem
Even for the same ingredient, the weight per cup changes based on how you measure:
| Method | 1 Cup All-Purpose Flour | Difference |
|---|---|---|
| Spooned & leveled | 125g | Baseline (most accurate) |
| Scooped from bag | 150-160g | +20-28% more flour |
| Sifted then measured | 110-115g | -8-12% less flour |
This 20-30% variation is why professional bakers always measure by weight. For best results, use a kitchen scale. When that's not possible, use the spoon and level method: spoon the ingredient into the cup, then level off with a straight edge.
Quick Reference: Common Ingredients
| Ingredient | 1 Cup (g) | 1 Tbsp (g) | Convert |
|---|---|---|---|
| All-Purpose Flour | 125g | 7.8g | Convert → |
| Granulated Sugar | 200g | 12.5g | Convert → |
| Brown Sugar (packed) | 220g | 13.8g | Convert → |
| Unsalted Butter | 227g | 14.2g | Convert → |
| Whole Milk | 244g | 15.3g | Convert → |
| Honey | 340g | 21.3g | Convert → |
| Cocoa Powder (unsweetened) | 86g | 5.4g | Convert → |
| Powdered Sugar (unsifted) | 120g | 7.5g | Convert → |
| Rolled Oats | 80g | 5.0g | Convert → |
| White Rice (uncooked) | 185g | 11.6g | Convert → |
US Cup vs. Other Standards
| Standard | Volume | Used In |
|---|---|---|
| US Customary Cup | 236.59 mL | United States |
| US Legal Cup | 240 mL | US nutrition labels |
| Metric Cup | 250 mL | Australia, New Zealand |
| Imperial Cup | 284.13 mL | UK (historical) |
| Japanese Cup (合) | 180.39 mL | Japan |
ConvertCal uses the US Customary Cup (236.59 mL) as the default standard, as it is the most widely used in English-language recipes.
Other Useful Formulas
Tablespoons to mL: mL = tablespoons × 14.787
Ounces to grams: grams = ounces × 28.3495
°F to °C: °C = (°F − 32) × 5/9