BMR Calculator

BMR Calculator is a free browser-based tool that helps you calculate your basal metabolic rate with activity breakdown. It is part of ToolsMonk's medical tools collection, so you can finish the job without downloading software, creating an account, or jumping between multiple websites.

This tool is especially useful for workflows such as finding your resting calorie burn as a basis for a diet plan, understanding the minimum calories your body needs, and combining with activity level to estimate daily needs (tdee). Because it runs directly in your browser, you can use it on desktop, tablet, or mobile while keeping the process fast and easy for one-off tasks as well as repeat work.

BMR Calculator is designed for people who want a practical, privacy-friendly workflow with instant results inside the larger ToolsMonk library.

BMR Calculator estimates your Basal Metabolic Rate — the calories your body burns at complete rest to sustain basic functions — from your age, sex, height, and weight, using a validated formula like Mifflin-St Jeor.

BMR is the foundation of calorie planning because it's the minimum energy your body needs before any movement. Everything else — activity, exercise, daily calorie targets for losing or gaining weight — builds on top of it, which is why getting a reliable baseline first makes the rest of a nutrition plan meaningful.

It's important to distinguish BMR from TDEE: BMR is the at-rest figure, while TDEE multiplies it by an activity factor to estimate what you actually burn in a day. The TDEE number is what you'd use to set eating targets, so BMR is step one and TDEE is step two.

Formula-based BMR is a strong estimate but not a personal measurement — real metabolism varies — so use it as a starting point and refine based on results over a few weeks. It's informational, not medical advice. Your details are processed in your browser and never uploaded. Pair it with the TDEE, Macro, and Calorie calculators for a complete plan.