Question 1

What is this calculator actually calculating?

Accepted Answer

Three things in sequence. First your resting expenditure using the Mifflin-St Jeor equation, then your total daily burn by applying an activity multiplier, then a calorie target by adding or subtracting a goal offset from that burn.

Only after that does it deal with macros: protein comes out of the budget first as grams per kilogram, fat takes a fixed share of the calories based on your carb preference, and carbohydrate receives whatever remains. That order is deliberate — it is the order the body-composition literature supports.

Question 2

How accurate is the calorie number?

Accepted Answer

The resting-expenditure part is reasonably good — Mifflin-St Jeor typically lands within about ten percent for most adults, which is why it displaced the older Harris-Benedict equation in practice. The activity multiplier is where the accuracy goes to die. Self-reported activity is optimistic almost universally, and a single rung of over-selection can shift the target by several hundred calories. If in doubt, choose the level below the one you first reached for and let two weeks of real-world data correct you.

Question 3

Why is the deficit only 17.5%?

Accepted Answer

Because it is the middle of the 15–20% range, and because aggressive deficits buy speed with tissue. Deeper cuts produce faster early scale movement, more lean-mass loss alongside the fat, a larger drop in resting expenditure, and a worse rebound profile once the diet ends. If you have dieted several times before, the case for moderation is stronger still — repeat dieters show larger adaptive drops in expenditure than the equations predict, which is exactly why our TDEE tool applies a separate correction for diet history.

Question 4

Low-carb or high-carb — which is right?

Accepted Answer

For non-diabetic adults, this is genuinely contested and there is no universal answer. Head-to-head trials at matched calories and adequate protein generally show equivalent body-composition outcomes; the differences that do show up are in how people feel, train and adhere. So it is a preference setting, not a prescription. Some insulin-resistant profiles report better appetite control on fewer carbohydrates; people training at high volumes usually perform better with more. Pick the one you will still be eating in six months.

Question 5

What do I actually do with these numbers?

Accepted Answer

Eat at the predicted intake for two full weeks and record your weight in the same conditions each morning. If the trend moves roughly as the target expects, the estimate fits you and you keep going. If it doesn't, adjust by 100–150 calories and give it another fortnight. Two weeks matters because water weight, glycogen and, for many women, cycle phase all move the scale far more than a few hundred calories do. Judging a target on four days of data is how people end up chasing noise.

Question 6

When should I talk to a doctor instead?

Accepted Answer

If your target comes out below your estimated resting expenditure and you still are not seeing change, if you are losing weight without trying, if you are pregnant or breastfeeding, or if you have a thyroid condition, diabetes or a history of disordered eating — those are clinical conversations, not calculator conversations. A calculator infers your metabolism from four inputs. Bloodwork measures it. Thyroid function, fasting insulin and glucose can all move the real answer well away from what an equation predicts, and none of them are visible from height and weight.

Level	Multiplier	What it means	Reality check
Sedentary	×1.20	Desk job, little deliberate movement	Most common honest answer
Lightly active	×1.375	Walking most days, occasional exercise	Where most people actually are
Moderately active	×1.55	3–4 structured sessions a week	Needs a real routine
Active	×1.725	5–6 sessions a week	Rare outside athletes
Very active	×1.90	Daily training or physical work	Most over-selected setting

Macro Calculator

No spreadsheet. It just asks.

Six steps, and the order is the whole argument

The activity multiplier is the weak link

Why protein is paid first

Macro questions people actually ask

Macros are arithmetic. Which protocol fits you isn't.