Start with phase guidance
The planner helps decide whether cutting, bulking, or recomposition makes sense first.
Built for fat loss, maintenance, and lean gains
See when your maintenance calories dip and your fat loss stalls.
Does your weight loss or weight gain stop after a while on a diet? MacroCodex helps you spot dips in maintenance calories from metabolic adaptation, then auto-adjusts your calorie target and macros so your plan stays aligned with your real maintenance calories (TDEE).
What MacroCodex helps you do
See when your maintenance calories change instead of assuming your old target still works.
Separate a real adaptation-driven stall from normal day-to-day water weight fluctuations.
Adjust calories and macros using your true maintenance calories (TDEE), not from guesswork or frustration.
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Green dashed line = Maintenance Calories (TDEE)
1. Your fat loss slows down If your calorie intake looks consistent but the green Maintenance Calories (TDEE) line drops, your old deficit may not be a real deficit anymore.
2. You can see why it happened Instead of guessing, the chart shows that your maintenance calories changed over time, which is exactly the kind of adaptation that can stall progress.
3. The app tells you the next move MacroCodex can tighten your calorie target and update your macros so your plan matches your current maintenance calories, not your old ones.
4. You stop reacting blindly You can tell whether progress stalled because of a real drop in Maintenance Calories (TDEE). You no longer react to day-to-day fluctuations that mostly come from water weight changes.
Why this beats a one-time Maintenance Calories (TDEE) calculator
It usually takes MacroCodex around 3 to 4 weeks of real intake and weight data to lock onto your true maintenance calories. Static Maintenance Calories (TDEE) calculators can be off by hundreds of calories for some people, because they do not learn from what your body is actually doing.
Most TDEE calculators rely on formulas derived from population averages using regression analysis. While formulas such as Katch-McArdle can account for body fat percentage, they cannot capture individual differences in metabolism, activity levels, hormones, or lifestyle. They also struggle to account for metabolic adaptation from long-term dieting, PCOS, thyroid disorders, and other factors that influence calorie needs.
See the full coaching flow
The app is not just a calculator. It helps users choose a direction, build a plan, review trend data, and keep the daily targets visible.
Turn guidance into a plan
Users choose the actual outcome and convert it into calories and macro targets.
Review progress with evidence
Weekly metrics show whether intake, weight trend, and balance support the current goal.
Track trend over noise
Rolling trend and progress cards keep users focused on signal instead of daily swings.
More ways MacroCodex keeps you on track
The app also helps with the small day-to-day decisions: staying active, following your targets, trusting your trend, and choosing the right phase at the right time.
Get nudged when activity drops
MacroCodex can warn you when you are turning sedentary and nudge you to become more active before it quietly slows progress.
Just eat the target and move forward
Your calorie and macro targets stay clear each day, so you can simply follow the plan and keep moving toward your goal with less friction.
Daily scale swings stop controlling you
Trend views make day-to-day weight changes easier to handle, so a random spike or drop does not need to send you into panic mode.
Use the planner to pick the right phase
The planner helps you decide when to cut, lean bulk, or recomp instead of bouncing between phases without a clear reason.
Frequently asked questions
Common questions about maintenance calories, logging, imports, and how MacroCodex adapts to your real data over time.
What if I am transgender?
Select the option that describes you best. The app will still work even if you choose the wrong sex, because it mainly relies on your calorie intake and weight data, not your sex.
Sex is only used for the initial estimate.
How does it calculate my maintenance calories?
MacroCodex uses the Katch-McArdle formula for the initial estimate. After that, it tunes your maintenance calories using your weight and calorie intake data.
It usually reaches good accuracy after about 3 weeks, or 21 days.
How does it compare to ChatGPT or TDEE calculators?
TDEE calculators like Calculator.net or TDEECalculator.net use the same formulas, so they share the same limitation: unreliable estimates.
If a beginner asks ChatGPT, "What are my maintenance calories?", ChatGPT can give them a number. But ask how it arrived at that number, and it will usually explain that it used a formula like Katch-McArdle, Harris-Benedict, or Mifflin-St Jeor to calculate BMR, then layered activity on top using an activity factor, PAL, or MET tables.
Dig deeper and those formulas come from statistical regressions based on averages from past populations. That means maintenance calories calculated this way can be off by hundreds of calories.
MacroCodex uses your calorie intake and weight data to figure out maintenance calories specific to your body, not the population average.
How does it compare to MacroFactor, Cronometer, or MyFitnessPal?
MacroFactor is a calorie tracking and maintenance calorie tracking app with a food database that is highly US-centric. In Europe, Yazio is more popular and has wider European food item coverage, while in other places people often use MyFitnessPal or Cronometer.
You can use Google Health Connect to connect MyFitnessPal, Cronometer, or another calorie tracking app with MacroCodex.
MacroCodex does not have calorie tracking features. It is strictly designed for maintenance calorie tracking.
Cronometer and MyFitnessPal may not have maintenance calorie tracking using an adaptive TDEE approach.
MacroFactor costs $71.99 per year, while pairing the free plan of Cronometer with MacroCodex is free.
You can import data from MacroFactor into MacroCodex and evaluate the accuracy of MacroCodex's maintenance calorie tracking without wasting time.
How soon will I see results?
MacroCodex takes about 3 weeks to figure out your maintenance calories. You should see weight gain or weight loss, depending on your goal, within 5 weeks.
Can I provide my own maintenance calories if I already know them?
Yes. During onboarding, the app gives you the option to enter your own maintenance calories.
Do I need to enter steps, cardio, or lifting calorie-burn data?
No. If you are in a surplus, your weight goes up. If you are in a deficit, your weight goes down. MacroCodex uses that relationship to estimate your true maintenance calories over time.
Comparing intake against your weight trend is more reliable than depending on wearable calorie-burn estimates.
Since MacroCodex uses your actual calorie intake and body weight trends over time, it can estimate your maintenance calories more accurately than wearables like Apple Watch, Garmin, or Whoop, while not requiring you to wear any sensor.
Does it support keto?
Yes. You can adjust your macros to fit keto or any other macro split you prefer.
How often do I need to log calorie intake?
For a reliable estimate, aim to log at least 7 out of 10 days. The app only needs your total calorie intake recorded once per day.
Does it support imports from calorie tracking or smart scale apps?
Yes. You can use Google Health Connect to import your data.
Can I import body fat percentage?
No. Most smart scales and watches are not reliable enough for an accurate body fat percentage estimate. We recommend using DEXA if available, or the US Navy formula or calipers inside the app.
For more detail, see the body fat guide.
What if I have a much more active day than usual?
You do not need to manually tweak the app day by day. If your overall activity level increases over time, your maintenance calorie estimate will rise as well.
If you choose to eat above or below target on a high-activity day, just log it normally. The algorithm will still adapt over time.