Every macro calculator on the internet asks the same four things. Your age, your height, your weight, and how active you are on a slider from “sedentary” to “very active.” You enter the numbers, it hands you a calorie target and a protein number, and you trust it. You probably should not.
Because here is what it never asks: what can you actually do? Two women use the same calculator at 150 pounds, 45 years old, five foot six. One has never picked up a weight and gets winded on the stairs. The other deadlifts her bodyweight and trains for strength three times a week. The calculator hands them the identical target. That is not a rounding error. That is the whole model being wrong for anyone who trains.
Why macro calculators ask the wrong questions
The standard calculator runs on the Mifflin-St Jeor equation plus an activity multiplier. It was built to estimate resting energy for the general population, and for that it is fine. The problem is the inputs. Age, height, weight, and sex are proxies. They stand in for the thing that actually drives your needs, which is how much muscle you carry and how hard you make it work.
For a sedentary person those proxies correlate well enough. For a woman who trains they fall apart, because the entire point of training is to change what your body is made of. You spent months making your bodyweight mean something different than it means for the average person your height. Then you hand that bodyweight to a formula that assumes you are average. Of course the number is off.
Why your bodyweight is a weak signal
Bodyweight cannot tell the difference between muscle and everything else. A woman who has built real strength and a woman at the same weight who has not get the same maintenance estimate and the same protein target, despite carrying different amounts of the tissue that burns calories and needs protein to repair.
Muscle is metabolically expensive. It costs energy to carry and energy to rebuild after you train it. So the more you have, the further a bodyweight-based estimate drifts from your real numbers. The calculator does not know you have it. It only sees the scale.
What should set your macro targets instead
What you can do is a live readout of what you are made of. Getting stronger is evidence of muscle a tape measure cannot see. How you move and how hard you train tell you about how much fuel you actually use in a day. These are not vanity stats. They are the closest thing to a free body-composition check you already have, updated every session.
The research points the same way. The International Society of Sports Nutrition puts protein for people who train at 1.4 to 2.0 grams per kilogram of bodyweight, climbing to 2.3 to 3.1 grams per kilogram of lean mass when you are leaning out and trying to hold onto muscle (ISSN position stand). Notice what moves those numbers: how and why you train, not your birthday. The more seriously you train, the more the generic recommendation underserves you.
How to set macros from your training
The fix is to start from what you do, not who you are on paper. Instead of an activity slider, describe the real training. What you can lift, how your conditioning looks, how many hard sessions land in a week. Those signals say more about your calorie and protein needs than your height ever will.
That is the model TrakMac is built on. When you set up your targets, it asks about how you train, then tunes your calorie and protein baselines to the person giving the answers instead of to a stranger who happens to share your stats. Then you log by voice and get on with your day. If you want the protein side specifically, we wrote about why your protein target is probably wrong, and about what to look for in a macro tracker built for strength.
You are not the average person your height. Stop eating like you are.
Download TrakMac
Your bodyweight is the one thing a macro calculator measures, and the one thing you have spent months making misleading. TrakMac sets your targets from how you actually train. Download TrakMac free. iOS, free to download.