Know your number before you change your diet
Almost every eating goal — losing fat, gaining muscle, or simply holding steady — starts from one figure: how many calories your body actually uses in a day. That’s your TDEE, and without it, diet advice is just guessing. This calculator estimates it in two steps: your resting burn (BMR) from the well-established Mifflin-St Jeor equation, scaled up by how active you are.
Once you have that maintenance number, the plan becomes simple arithmetic. Eat around it to stay the same, a few hundred below it to lose gradually, a few hundred above to gain. The tool shows all three so you can see the trade-offs at a glance. Treat the result as a well-informed starting point rather than a precise prescription — bodies vary, so track how you respond over a few weeks and adjust. It isn’t medical advice.
