Posted on Oct 21, 2026 Last updated: 10/22/2026, 11:32:34 AM Estimated reading time: 2 min

Looking for a Jeremy Ethier calorie calculator?

If you follow Jeremy Ethier and Built With Science, your daily calorie target starts with an estimate of maintenance calories, also called total daily energy expenditure (TDEE). Eating around maintenance aims to keep weight stable; eating below or above it aims for weight loss or gain. Compare that first estimate with your actual intake and weight trend over the following weeks.

For the original tool, visit the official Built With Science calorie calculator. It uses a formula based on the Katch-McArdle equation, which incorporates estimated lean body mass. Jeremy Ethier's TDEE guide explains the starting-estimate approach. This is an independent guide; MacroCodex is not affiliated with or endorsed by Jeremy Ethier or Built With Science and does not reproduce their calculator.

MacroCodex calorie and macro planning screen

alt text
Google Playstore Review of MacroCodex

Our claim: See measurable weight gain or weight loss results within 2–3 weeks of using MacroCodex. Many users start seeing results as early as the first week.

Verify playstore reviews here: https://play.google.com/store/apps/details?id=com.macrocodex.app

alt text
MacroCodex user in the Telegram community.

Verify Telegram Community reviews here: https://macrocodex.app/community/

Calculate a daily calorie target for free

  1. Open MacroCodex and enter your details to get an initial maintenance-calorie estimate.
  2. Choose maintenance, weight loss, or weight gain. The app uses your maintenance estimate to set a daily calorie target.
  3. Record your calorie intake and body weight consistently. MacroCodex updates its maintenance estimate and targets as it learns from your trend.

alt text
MacroCodex free app continuously tracks maintenance calories using State Space Neural Network.

A body-fat input is still an estimate. A formula that uses lean body mass depends on the accuracy of that input as well as your activity estimate. Rather than repeatedly changing your estimated body-fat percentage to chase a different answer, check whether your recorded intake produces the expected weight trend across weeks.

MacroCodex is free and has no ads or subscription. It asks you to enter daily calorie totals; if you want a food diary, you can use a separate logger such as CalorieCodex. Short-term scale changes can reflect water, glycogen, and food in your digestive system.

Want the details behind the estimate? See how adaptive TDEE works and our calorie-tracking guide.