How many calories are in bread?
A medium slice of white bread — around 36 g (1.3 oz) — is about 90 kcal. That figure is less fixed than it sounds, because “a slice” is not a unit. Thin-sliced, medium and thick loaves differ by nearly half, and most people never weigh a slice in their lives.
Per portion
| Portion | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Thin slice, white (25 g / 0.9 oz) | ~65 kcal | 2 g | 12 g | 0.5 g |
| Medium slice, white (36 g / 1.3 oz) | ~90 kcal | 3 g | 17 g | 1 g |
| Thick slice, white (44 g / 1.6 oz) | ~110 kcal | 4 g | 21 g | 1.5 g |
| Medium slice, wholemeal (36 g) | ~85 kcal | 4 g | 15 g | 1 g |
| Slice of sourdough (50 g / 1.8 oz) | ~130 kcal | 5 g | 25 g | 1 g |
| Plain bagel (95 g / 3.4 oz) | ~250 kcal | 10 g | 49 g | 1.5 g |
| Plain naan (90 g / 3.2 oz) | ~290 kcal | 8 g | 50 g | 6 g |
| 100 g (3.5 oz) white bread, about three medium slices | ~265 kcal | 9 g | 49 g | 3 g |
A bagel is not a snack-sized item: it is close to three slices of bread by weight and energy. Loaves cut at home run thicker than machine-sliced ones.
What changes the number
Thickness, before anything else. Most loaves sit between 240 and 275 kcal per 100 g regardless of colour, so the slice weight does the work. If you eat two slices a day, the gap between thin-sliced and thick is roughly 90 kcal a day — about 2,500 kcal over a month, which is not nothing against maintenance.
Loaf type, less than expected. White, brown and wholemeal land within about 20 kcal per 100 g of each other. Seeded and nut loaves are genuinely higher, 280–320 kcal per 100 g, because seeds are fat. Enriched breads — brioche, challah, milk bread — carry butter, egg and sugar and can reach 350–400 kcal per 100 g.
What goes on top, which usually exceeds the bread. The part worth measuring:
| Topping | Approx. kcal |
|---|---|
| 10 g (2 tsp) butter | ~75 |
| 1 tbsp olive oil | ~120 |
| 20 g peanut butter | ~120 |
| 1 tbsp mayonnaise | ~95 |
| 20 g cheddar | ~80 |
| 15 g jam | ~40 |
| 50 g avocado (a quarter) | ~80 |
Two medium slices are about 180 kcal. Butter them, add cheese, and the bread is under half the sandwich — a generous cheese toastie is a 500 kcal item.
Where it fits in a deficit
Bread is middling on density — roughly three times a boiled potato per 100 g — and modest on satiety for its calories, because it is dry, quick to eat and easy to eat more of. That makes it a poor choice for volume and a perfectly reasonable one for convenience.
Wholemeal has a real edge in fibre, which helps fullness, and the protein in bread is low enough that a sandwich needs a proper filling rather than a spread. None of it is off-limits in a calorie deficit: the practical move is to decide your slice count in advance, since bread is easy to eat absent-mindedly. Compare it with the high-volume options if a meal needs to feel bigger.
Toasting, staling and the freezer claim
Toasting does not change the calories in a slice. It drives off water, so the slice gets lighter and its kcal per gram rises, while the slice is exactly what it was.
Freezing bread then toasting it does raise its resistant starch a little, blunting the blood-glucose response. The energy saving is a few per cent at best, and well inside the margin of how thickly you cut the next slice. If colour is your guide to which loaf to buy, see brown bread — the word is doing less work than you think.
Figures are typical values and vary by variety, size and preparation. General information, not medical advice.