How accurate is this diet plan calculator?

This calculator uses the Mifflin-St Jeor equation, which is widely considered the most accurate formula for estimating Basal Metabolic Rate (BMR) in healthy adults. However, all calculators provide an estimate. Your actual energy needs can vary based on genetics, body composition, and health conditions. Use this result as a starting point and adjust based on your real-world progress.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body needs to perform its most basic functions (like breathing, circulation, and cell production) while at rest. TDEE (Total Daily Energy Expenditure) is your BMR plus all the calories you burn from physical activity, digestion, and daily tasks. Your TDEE is the 'maintenance' calorie level you need to stay at your current weight.

Why does this calculator use Mifflin-St Jeor instead of Harris-Benedict?

The Mifflin-St Jeor equation (published in 1990) has been shown in multiple studies to be more accurate for most people than the older Harris-Benedict equation (published in 1919). It is now considered the standard in many clinical and nutrition settings.

What should my macronutrient (protein, carb, fat) split be?

The ideal 'macro' split depends on your personal goals, preferences, and how your body responds. A common 'Balanced' split is 40% Carbs, 30% Protein, 30% Fat. Athletes or those on a 'Low Carb' diet might aim for 25% Carbs, 40% Protein, 35% Fat. We provide several examples, but you should experiment to find what works best for you or consult a registered dietitian.

How often should I recalculate my calorie needs?

It's a good idea to recalculate your TDEE every time you have a significant change in weight (e.g., you lose or gain 5-10 kg / 10-20 lbs) or if your activity level changes (e.g., you start a new, more active job or begin a new workout routine). This ensures your calorie target stays aligned with your body's current needs.

Diet Plan Calculator - Calculate Your Daily Calorie Needs

Calculate your daily calorie needs for weight loss, maintenance, or gain based on the Mifflin-St Jeor formula. Get a personalized diet plan macro-breakdown.

Switch easily between units and watch your macros update with each input.

Height (cm)

Weight (kg)

Age

Gender

Activity level

Goal modifier (calories)

This calculator uses the Mifflin-St Jeor equation, your chosen activity multiplier, and the goal modifier you select to predict your adjusted daily calories and macro splits.

Your Daily Calorie Plan

Enter your personal details and press Calculate to see your BMR, TDEE, and goal calories together with sample macro splits.

How to Use This Calculator

Start by choosing metric or imperial units, then provide your age, gender, height, and weight.

Pick the activity level that most closely mirrors your weekly routine and select a goal modifier to gain, lose, or maintain weight.

Hit Calculate to see your BMR (basal metabolic rate), TDEE (total daily energy expenditure), and the adjusted calorie budget that matches your goal.

Methodology

This calculator uses the modern Mifflin-St Jeor formulas for BMR, multiplies the result by your activity factor to approximate TDEE, and then applies your goal modifier. Macronutrient tables assume 4 calories per gram of protein or carbohydrate and 9 calories per gram of fat.

Numeric entries are validated so you always see positive, sensible calorie estimates.
The unit tabs keep metric and imperial inputs synchronized behind the scenes.
Goal modifiers can be negative (calorie deficit) or positive (calorie surplus) to reflect weight loss or weight gain plans.

Results are estimates based on scientific equations; real-world energy needs depend on body composition, genetics, and lifestyle. Use this as a planning tool and adjust as you monitor progress.

Full original guide (expanded)

Why Use This Calculator

Based on the modern, accurate Mifflin-St Jeor equation.
Get instant calorie targets for weight loss, gain, or maintenance.
See example macronutrient splits to start planning your meals.
Fully accessible (WCAG 2.1 AA) and mobile-friendly design.
Transparent methodology with full formula and example.

Related Health Tools

Editorial Notes

CalcDomain content is created for educational purposes and is reviewed for clarity, accuracy, and transparency. Inputs and assumptions are shown directly in the interface so you can verify how results are produced.

Verified by Ugo Candido on January 19, 2026. Profile · LinkedIn

Ad placement (300×600) — placeholder content preserved from the original layout.

Formulas

Basal Metabolic Rate (Mifflin-St Jeor):

Male: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5

Female: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161

TDEE: TDEE = BMR × Activity Multiplier

Goal Calories: Goal Calories = TDEE + Goal Modifier

Citations

Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/

Health & Fitness — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/health-fitness

Diet & Nutrition — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/subcategories/diet-nutrition

https://doi.org/10.1093/ajcn/51.2.241 — doi.org · Accessed 2026-01-19
https://doi.org/10.1093/ajcn/51.2.241

BMI Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/bmi-calculator

Macronutrient Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/macro

Body Fat Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/body-fat

TDEE Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/tdee

Changelog

Version: 0.1.0-draft · Last code update: 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

✓ Verified by Ugo Candido Last Updated: 2026-01-19 Version 0.1.0-draft

Version 1.5.0