A medium banana (about 118g, 7-8 inches long) has 27g of carbs, 14g of which is sugar, with 3g of fiber — net carbs land around 24g.
By size
| Size | Weight | Carbs |
|---|---|---|
| Extra small (<6") | 81g | 19g |
| Small (6-7") | 101g | 23g |
| Medium (7-8") | 118g | 27g |
| Large (8-9") | 136g | 31g |
| Extra large (>9") | 152g | 35g |
Ripeness matters more than people think
As a banana ripens, starch converts to sugar:
- **Green banana**: ~80% starch, lower glycemic index (~30)
- **Yellow banana**: balanced, GI around 50
- **Spotty / brown banana**: mostly sugar, GI around 60
The *total* carbs barely change with ripeness — but the speed they hit your blood does.
Blood sugar impact
A medium ripe banana raises glucose 30-50 mg/dL in most people, peaking around 45 minutes. Pairing with peanut butter or Greek yogurt blunts the spike significantly.
Comparison to other fruit (per serving)
- Apple (medium): 25g
- Orange (medium): 15g
- Strawberries (1 cup): 12g
- Grapes (1 cup): 16g