BMR Calculator

How to use BMR Calculator

1. Open BMR Calculator in your browser — it loads instantly and works offline once cached.
2. Enter your values in the input fields. Every field is labelled so you know exactly what to type.
3. The result updates automatically as you type — there is no "submit" round-trip to a server.
4. Adjust any input to compare scenarios and see how the outcome changes in real time.
5. Copy or note the result. Nothing you enter is stored or sent anywhere.

Why use BMR Calculator?

• 100% free with no limits, no sign-up and no watermarks.
• Private by design — your data are processed in your browser and never uploaded to a server.
• Fast and lightweight, with instant results even on a phone or a slow connection.
• Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
• Part of a full health & fitness suite, so related bmr tasks are one click away.

What people use BMR Calculator for

• Estimating the energy your body uses at complete rest.
• Establishing a baseline before calculating daily calorie needs.
• Understanding roughly how many calories maintain your current weight.

BMR Calculator: limits and things worth knowing

• BMR is the energy needed for basic function at rest — it does not include any activity. The Mifflin-St Jeor equation is the current standard and is more accurate than the older Harris-Benedict.
• Multiply BMR by an activity factor (1.2 sedentary to about 1.9 for very heavy training) to get total daily expenditure, which is the figure that actually determines weight change.
• Any equation is an estimate with individual variation of roughly ±10%, because it cannot measure your body composition, thyroid function or genetics.
• BMR falls as weight falls, which is why a deficit that worked at the start of a diet stops working later.
• General information only, not medical or dietary advice.

Is it private and secure?

Your privacy is built in. BMR Calculator runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.

Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.

You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.

Learn more

Why Browser-Based Tools Are Safer for Your Files — Most online converters upload your files to a server. Client-side tools don't. Here's why that difference matters for privacy.