SelHealth Calculators

Calories Calculator

Estimate your daily calorie needs with SelHealth and use the result as a practical starting point for maintenance, loss, or gain goals.

How to use this tool
  1. Enter age, sex, body measurements, and activity level.
  2. Review the estimated maintenance calories.
  3. Use the number as a starting point, then adjust gradually based on progress.
💪 Fitness & Body
SelHealth dark calculator system

BMI Calculator

Enter your height and weight to calculate your body mass index.

Adults Screening only
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: WHO • Evidence level: Reference-based educational estimate
Educational weight-status classification for adults; BMI is a screening measure and does not diagnose body composition on its own.

Calories Calculator

Estimate BMR and TDEE based on your body data and activity.

Estimate Nutrition planning
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: Mifflin-St Jeor • Evidence level: Reference-based educational estimate
Daily calorie output is an educational estimate based on BMR and activity; real needs vary with body composition, illness, medication, and training load.

Body Fat Calculator

Uses the US Navy formula for estimation.

Estimate Tape-based
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: US Navy / ACSM • Evidence level: Reference-based educational estimate
This method estimates body fat from circumference measures and is useful for education and trend tracking, not clinical diagnosis.

Ideal Weight

Quick estimate using a BMI-centered healthy range.

Estimate Range guidance
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: WHO BMI range • Evidence level: Reference-based educational estimate
Healthy-weight range is an educational BMI-based estimate and may not fit athletes, edema states, or unusual body composition.

Water Intake Calculator

Simple daily estimate based on body weight and activity.

Daily target Lifestyle
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: EFSA / IOM • Evidence level: Reference-based educational estimate
Exercise-related water targets are estimates and may need adjustment for climate, sweat losses, kidney disease, and medical advice.

Calories Burned

Estimate calories burned using MET activity values.

Training estimate Lifestyle
Wellness Estimate Medically reviewed • Last reviewed: 2026-03 • Source: Compendium of Physical Activities • Evidence level: Reference-based educational estimate
Calories burned is an exercise estimate based on MET values and body weight; it should not be treated as an exact compensation target for food intake.

Macro Calculator

Estimate daily protein, carbs, and fats based on calories and your goal.

Daily target Nutrition planning
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: ISSN • Evidence level: Reference-based educational estimate
Macro targets are educational planning estimates and should be individualized for athletes, disease states, pregnancy, or eating disorders.

Protein Intake

Estimate a practical daily protein target based on body weight and goal.

Daily target Nutrition planning
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: ISSN / Morton et al. • Evidence level: Reference-based educational estimate
Protein guidance here is an educational daily target for active adults and may need clinical adjustment in kidney disease or special populations.

Waist-to-Height Ratio

Estimate your waist-to-height ratio as a simple health screening metric.

Screening only Self-check
Screening Tool Medically reviewed • Last reviewed: 2026-03 • Source: Ashwell • Evidence level: Guideline-framed screening support
Waist-to-height ratio is a screening marker for central adiposity and cardiometabolic risk, not a stand-alone diagnosis.

Lean Body Mass

Estimate lean body mass and fat mass using a simple formula.

Estimate Non-lab estimate
Educational Tool Medically reviewed • Last reviewed: 2026-03 • Source: Boer formula • Evidence level: Reference-based educational estimate
Lean-mass output here is an educational estimate and should not be interpreted as a direct body composition scan equivalent.

Vitamins Guide

A quick educational lookup for common vitamin roles.

Educational Lifestyle
Vitamin D
Bones + immunity
Low levels may affect bone health and general wellness. Common sources: sunlight, fatty fish, fortified foods.
Vitamin C
Antioxidant + skin + immunity
Supports collagen formation and antioxidant defense. Common sources: citrus, kiwi, berries, peppers.
Vitamin B12
Energy + nerves + red blood cells
Important for nerve function and red blood cell formation. Common sources: animal foods, fortified products.
Magnesium
Muscles + relaxation + recovery
Supports muscle function, sleep quality, and recovery. Common sources: nuts, seeds, legumes, dark greens.
Iron
Oxygen transport + energy
Low iron may relate to fatigue in some cases. Common sources: red meat, legumes, spinach, fortified cereals.
Calcium
Bones + teeth + muscle function
Important for bone structure and muscle contraction. Common sources: dairy, fortified milk, sardines, tofu.
Omega-3
Heart + brain support
Often discussed for cardiovascular and cognitive support. Common sources: salmon, sardines, flax, chia.
Zinc
Immunity + skin + recovery
Important for immune function and wound healing. Common sources: meat, shellfish, legumes, seeds.
This guide is educational only. It does not replace lab testing or personalized medical advice.

My Progress

Track your BMI and weight entries locally on this device.

Trend check Educational
Tracking is currently disabled.
No saved progress yet.
What this tool helps you do

This calculator estimates daily calorie needs using your body data and activity level. It helps you set a more realistic baseline before adjusting for weight loss, maintenance, or gain goals.

How to read your result

Starting point

The estimate is a baseline, not a guarantee. Real-life needs change with activity, sleep, stress, and adherence.

Frequently asked questions
Does this number stay constant?

No. Your actual needs may change over time with routine, body composition, and activity changes.

Related tools

These supporting tools help you turn the calorie estimate into a more practical nutrition and activity plan.

Macro Calculator Open calculator → Protein Intake Open calculator → Calories Burned Open calculator →