Free online tool
BMR Calculator
Estimate your Basal Metabolic Rate (BMR) and total daily energy expenditure (TDEE).
What is BMR?
BMR is the number of calories your body burns at complete rest, just to keep your organs running. It accounts for around 60–75% of the calories most people burn in a day. This calculator uses the Mifflin-St Jeor equation, the modern standard endorsed by dietitians because it's more accurate for the general population than older formulas.
Using TDEE for weight goals
Multiply BMR by an activity factor to get TDEE — total daily energy expenditure. Eat that many calories to maintain weight, subtract roughly 500 per day to lose about half a kilogram per week, or add 250–500 for lean bulking. Treat the number as a starting estimate and adjust based on how your body actually responds over a few weeks.
+How accurate is this?
Within about 10% for most healthy adults. Very muscular or very lean individuals may need a body-composition-based formula for more accuracy.
+Should I go below my BMR to lose weight faster?
No. Eating well below your BMR long-term causes muscle loss and hormonal issues. A moderate deficit is more sustainable.
Why use the BMR Calculator on ToolNest?
The BMR Calculator is one of more than forty free browser-based utilities we maintain on ToolNest. Every tool on the site is engineered around the same three promises: it must be fast, it must protect your privacy, and it must be genuinely useful without hiding features behind an account, a paywall, or an email capture form. Whether you use the BMR Calculatoronce a month or several times a day, it should feel like a native part of your workflow — open the tab, get the result, move on.
Everything happens directly inside your web browser. When you type, paste, or upload something into the BMR Calculator, that data never leaves your device. There is no server round-trip, no logging, no analytics pixel watching your keystrokes, and no third-party API silently receiving a copy of your input. Closing the browser tab is the same as clearing your session. This is a deliberate design choice: too many free "online tools" quietly funnel user content through remote servers, and we do not think a utility as small as this one justifies that risk.
Speed is the other pillar. The BMR Calculator loads on a cold connection in well under a second and stays responsive on older phones, low-power laptops, and metered mobile networks. There are no heavy frameworks layered on top of the tool, no autoplay video ads, and no blocking third-party scripts. Search engines like Google reward pages that load quickly and stay interactive, but more importantly, so do human visitors who came here to get one specific job done.
If the BMR Calculator saves you time, the best thing you can do is bookmark this page and share it with a colleague or classmate who might need it. We also welcome direct feedback — bug reports, feature requests, and suggestions for entirely new tools all go to the same inbox and are read by a human. The best tools on ToolNest started life as a one-line reader email, and this page will keep improving as long as people keep telling us what they wish it did better.