How many kilojoules are in banana bread?
A thick cafe slice of banana bread (about 150 g) is about 2,130 kJ (509 Cal), and a standard cafe slice about 1,700 kJ. Toast it and add the two pats of butter it usually comes with and you're near 2,750 kJ (657 Cal). Australian banana bread runs about 1,300 to 1,470 kJ per 100 g - closer to cake than to bread. It's the size of the slice and the butter that decide the number, and it's right there in kilojoules on the label.
Key numbers
- Banana bread ~1,300 to 1,470 kJ/100 g (typical ~1,420)
- Thick cafe slice ~2,130 kJ
- Each 10 g pat of butter ~310 kJ
- Toasted thick slice + 2 butters ~2,750 kJ
- Thin supermarket-loaf slice ~1,000 kJ
Banana bread by the slice
| Serve | Energy | Calories |
|---|---|---|
| Thin supermarket-loaf slice (~70 g) | ~1,000 kJ | 239 Cal |
| Standard cafe slice (~120 g) | ~1,700 kJ | 406 Cal |
| Thick cafe slice (~150 g) | ~2,130 kJ | 509 Cal |
| Thick slice, toasted, 2 pats of butter | ~2,750 kJ | 657 Cal |
| Banana muffin, commercial (~130 g) | ~1,840 kJ | 440 Cal |
| Friand, commercial (~80 g) | ~1,310 kJ | 313 Cal |
What moves the number
| Add or swap | Change |
|---|---|
| 1 pat of butter (10 g) | ~+310 kJ |
| 2 pats of butter (20 g) | ~+615 kJ |
| Toasting it | about the same kJ |
| Thick slice to a thin one (150 g to 70 g) | ~-1,130 kJ |
| Protein-style loaf vs bakery loaf, per 100 g | ~-300 to -380 kJ |
| Add a large full cream flat white | ~+724 kJ |
The cafe classic, minus the lecture
- It's cake wearing a bread name. Bakery and supermarket banana breads sit around 1,420 kJ per 100 g, about the same as a commercial banana muffin (1,412) or banana cake (1,456). The name just sounds lighter.
- The slice is the variable. A thin slice off a supermarket loaf is about 70 g; a cafe slice is often 120 to 150 g, double the size. Same bread, twice the number.
- The butter is the quiet one. Butter is about 3,070 kJ per 100 g, so each 10 g pat is about 310 kJ. Two pats add nearly a third again on top of a thick slice.
- Toasting changes nothing. It drives off a little water and adds crunch, not kilojoules.
- Brunch is meant to be nice. A toasted slice and a large flat white is about 3,470 kJ. Knowing that just means you choose it on purpose, then enjoy it.
Stop guessing the number
OzCal logs a cafe order in about five seconds: snap it, scan the barcode or search it - or just say "toasted banana bread with butter and a large flat white". Kilojoules the way the label shows them, on 86,832 verified Australian foods.
Common questions
How many kilojoules in a slice of banana bread?
A thick cafe slice (~150 g) is about 2,130 kJ; a standard cafe slice (~120 g) about 1,700 kJ; a thin supermarket-loaf slice near 1,000 kJ.
How much does butter add?
About 310 kJ a 10 g pat, so two pats is about 615 kJ. Toasted thick slice with two pats: near 2,750 kJ.
Is banana bread lighter than a muffin?
About the same per 100 g (both ~1,410 to 1,420 kJ). A 130 g banana muffin is about 1,840 kJ, between a standard and a thick slice.
Does toasting change the kilojoules?
No. Toasting removes a little water, not energy. Slice size and the butter move the number.
Is there a lower-kJ banana bread?
Protein-style loaves sit near 1,000 to 1,120 kJ per 100 g, against ~1,420 for a bakery loaf. A thinner slice and one pat of butter moves it more.
Keep reading
Citing this page. OzCal (2026). "Banana Bread Kilojoules: The Cafe Slice in kJ | OzCal". Retrieved from https://ozcal.com.au/kilojoules/banana-bread. Last updated 2026-10-09. Figures are per the serve stated in each row, converted at 1 Cal = 4.184 kJ.