Nutrition 4 min read
How the Ardenti calculator works
Most calculators hand you one number and one macro split. Here is what ours does instead, with every formula behind it.
A TDEE calculator estimates how many calories you burn in a day. A macro calculator turns that into protein, carbs and fat. Ours does both, and it is the same engine that runs the Ardenti app. This is how it gets to your numbers, in the order it works them out.
1. What you burn at rest
Everything starts with your resting burn, the energy your body uses just to keep going. If you tell the calculator your body fat, it uses the Katch-McArdle formula, which works from your lean body mass: everything in your body that is not fat.
Resting burn = 370 + 21.6 × lean body mass in kilograms
Two people at the same weight can carry very different amounts of muscle, and muscle is what drives resting burn. If you leave body fat out, the calculator uses Mifflin-St Jeor instead, which estimates from your weight, height, age and sex. The result tells you which one it used.
2. What your days add
Most calculators ask for a single activity level. We ask two questions: what your ordinary day looks like, and how much you train. A desk job with hard training is not the same as an active job with none, and one dropdown cannot tell them apart. The two answers combine into one multiplier, and your resting burn times that multiplier is your TDEE, your maintenance calories.
3. Calories for your goal
To lose or gain, the calculator uses the standard estimate of about 3,500 calories per pound, spread across the week. So half a pound a week is roughly 250 calories a day below or above maintenance.
There are two limits it will not cross. A weight-loss target never drops more than 25% below your maintenance, and it never goes under a fixed daily minimum. If the pace you pick would need a steeper cut than that, you get the limit instead.
The exact daily minimums
1,200 calories a day for women and 1,500 for men. These are guardrails, the lowest figure the calculator will ever show. They are not targets or recommendations, and most people's numbers sit well above them.
4. Protein comes first
Your protein target is set before anything else, from your lean body mass rather than your total weight: 1.1 grams per pound of lean mass on three of the four Fuel Sources. If you did not enter your body fat, the calculator estimates it and says so.
5. Carbs and fat share the rest
Once protein is set, the calories left over are split between carbs and fat. This is where a single fixed split would normally appear. Instead you choose a Fuel Source, and each one is a range, not one number.
| Fuel Source | What it is | Carbs, of what is left |
|---|---|---|
| Keto Ignite | Very low carb | 5% to 15% |
| Ember | Recovery fuel | 20% to 45% |
| Steady Flame | Balanced | 45% to 65% |
| Blaze | Performance fuel | 65% to 75% |
Fat takes whatever carbs do not. Keto Ignite is the exception on protein: it uses a lower setting of 0.7 grams per pound of lean mass. Your calories are the same on every Fuel Source. Only the split changes.
What a calculator cannot do
Every number above is an estimate from averages. Your real maintenance might sit a little higher or lower, and it shifts over time. A calculator has no way to find that out, because it only sees you once.
That is the part the app adds. Each week it looks at your weight trend across at least two weeks of weigh-ins, compares it with the pace you chose, and moves your calories by no more than 200 if they need to move. If the week was hard to follow, your targets stay where they are.
You do not need the app to use the calculator. Run your own numbers, as often as you like.
Ardenti is a wellness tool. These figures are general estimates, not medical advice. Talk to your doctor before changing how you eat if you have a medical condition, are pregnant, or have a history of disordered eating.