BMR Calculator

BMR - What Your Body Burns Just Staying Alive

Think of BMR as your body's "idle speed." It's how many calories you'd burn if you literally stayed in bed all day doing nothing - just breathing, keeping your heart beating, maintaining body temperature, and all that behind-the-scenes stuff your body does without you thinking about it.

Making Sense of Your Number

Your BMR is basically your body's minimum fuel requirement. But unless you're planning to be a couch potato forever, you need more calories than just your BMR. Here's how it breaks down when you factor in actual living:

• Sedentary: Take your BMR and multiply by 1.2 (You sit most of the time)
• Light Activity: BMR × 1.375 (You exercise maybe once or twice a week)
• Moderate Activity: BMR × 1.55 (Regular gym-goer, 3-5 times weekly)
• Very Active: BMR × 1.725 (Exercise is practically your second job)
• Extra Active: BMR × 1.9 (Marathon training or construction work level)

Why Your BMR Is What It Is

• Age - Unfortunately, your metabolism slows down as you get older. Thanks, biology.
• Gender - Men typically burn more calories at rest than women. Blame it on generally having more muscle mass.
• Body Composition - Muscle tissue is hungry stuff. The more muscle you have, the more calories you burn even while watching Netflix.
• Genetics - Some people won the metabolism lottery, others didn't. Life's not fair sometimes.
• Hormones - Your thyroid is basically your metabolism's control center. When it's off, everything gets weird.

Why This Matters for Your Goals

Knowing your BMR isn't just nerdy trivia - it's actually useful:
You can set weight goals that make sense instead of crash dieting and wondering why you feel terrible. You'll understand why that friend who eats pizza all the time stays skinny (spoiler: they probably have a higher BMR). Plus, you can make smarter food choices knowing roughly how much fuel your body actually needs.

The Fine Print

We're using the Mifflin-St Jeor equation here because it's pretty reliable for most people. But your actual BMR might be different - maybe you have a medical condition, maybe you're on medication, maybe your body just marches to its own drummer.
Don't use this as an excuse to eat 800 calories a day or anything crazy like that. If you're thinking about major diet changes, talk to someone who actually knows what they're doing first.
And remember - exercise isn't just about burning calories. Your body needs to move to stay healthy, regardless of what the scale says.