BMI reference chart
BMI (Body Mass Index) compares your weight to your height. Here's how the numbers are generally classified, so you can see where your result falls:
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
Based on the standard WHO classification. For Asian populations, some health guidelines use lower cut-offs (overweight from around 23). BMI is a general screening tool — it doesn't account for muscle mass or body build, so treat it as a guide, not a diagnosis.
How the calculator works
First, it estimates your Basal Metabolic Rate (BMR) — the energy your body uses at rest — from your sex, age, height, and weight using the widely-used Mifflin-St Jeor equation. It multiplies that by your activity level for your total daily energy needs, then adjusts for your goal: a moderate deficit to lose weight, maintenance for proper nutrition, or a small surplus to gain weight or build muscle. Finally, it splits those calories into macros according to your chosen diet style.
The three diet styles
Keto (low-carb) is our specialty — and for good reason. Carbs are kept very low (~25g) to switch your body into fat-burning ketosis, which is known for steady, all-day energy, fewer cravings, and natural appetite control that makes a calorie deficit far easier to stick to, plus steadier blood sugar. That combination is why so many people find keto the most sustainable way to lose weight and keep it off. For comparison, high-protein sets protein highest with moderate carbs and fat (no ketosis required; often used for muscle building), and balanced is a classic even split for everyday nutrition. Across all three, protein preserves and builds muscle (especially in a deficit or as we age), while fat and carbs supply energy.
New to keto specifically? Start with our Keto for Beginners guide, or read how keto helps you lose weight.
The easy part: we cook it for you
Knowing your macros is one thing — hitting them every day is another. That's what Meals by Lily removes. We offer keto meal plans (with larger portions available on request), freshly cooked and delivered, so you don't have to weigh, count, or plan. Our plans are keto-based — we don't currently offer separate high-protein or muscle-gain plans, so the calculator's other modes are there as a general guide. Ready to eat keto without the daily effort? See our keto meal plans →
Common questions
What are macros?
Fat, protein, and carbohydrates — the three nutrients that provide calories. Your ideal split depends on your diet style and goal.
What's the difference between keto and high-protein macros?
Keto keeps carbs very low and fat high to stay in ketosis. High-protein keeps protein highest (to build/keep muscle) with moderate carbs and fat, and doesn't require ketosis.
How much protein do I need to build muscle?
Roughly 1.6–2.2g per kg of body weight, with the higher end for active people and muscle building. The calculator sets this based on your diet style and goal.
Are these numbers exact?
They're solid estimates and a great starting point — adjust based on your real-world results, and get personalized advice from a professional if you have health conditions.