Calculate Your Base Calories (BMR)
Use this calculator to estimate your base calories (Basal Metabolic Rate), maintenance calories, and practical intake targets.
Formula used: Mifflin–St Jeor equation. Results are estimates, not medical advice.
What are “base calories”?
Base calories are the calories your body burns at rest to keep you alive and functioning. This number is called your BMR (Basal Metabolic Rate). Even if you stayed in bed all day, your body still needs energy for breathing, circulation, temperature control, and organ function.
Knowing your base calories is useful because it gives you a realistic starting point for nutrition planning. From there, you can estimate maintenance calories (what keeps your weight stable), then choose a mild deficit for fat loss or a small surplus for lean gain.
How this calculator works
Step 1: Estimate BMR
The calculator uses the Mifflin–St Jeor formula, one of the most widely used equations in sports nutrition and weight management.
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2: Estimate maintenance calories (TDEE)
We multiply BMR by your activity factor to estimate your Total Daily Energy Expenditure (TDEE), also called maintenance calories. This is the daily intake where body weight typically stays about the same over time.
Step 3: Suggest practical targets
You’ll also see suggested calorie targets for:
- Mild fat loss (about 10% below maintenance)
- Fat loss (about 20% below maintenance)
- Lean gain (about 10% above maintenance)
How to use your calorie numbers correctly
A calorie calculator gives a strong estimate, but your real-world response matters most. Use your result for 2-3 weeks, then adjust based on trend data.
- Weigh yourself 3-7 times per week under similar conditions.
- Track average weekly weight, not one-day changes.
- If weight isn’t moving as expected, adjust intake by 100-200 calories/day.
- Keep protein high and strength train to preserve muscle during fat loss.
Common mistakes people make
- Choosing an activity level that’s too high: this can overestimate maintenance calories.
- Ignoring weekends: weekday deficits can be erased by weekend overeating.
- Changing calories too often: wait long enough to see real trends.
- Not tracking portions: “healthy” foods still contain calories.
Quick FAQ
Is BMR the same as maintenance calories?
No. BMR is your at-rest baseline. Maintenance includes movement, exercise, digestion, and daily activity.
How accurate is this base calories calculator?
Most equations are reasonably accurate for many adults, but individual differences can be significant. Think of the result as a starting estimate, then personalize through consistent tracking.
Should I eat below my BMR to lose weight faster?
Usually not a good idea. Extremely low calories can hurt performance, recovery, and adherence. A moderate deficit is typically safer and more sustainable.
Bottom line
If your goal is fat loss, maintenance, or muscle gain, knowing your base calories is the first useful number. Start with the estimate, stay consistent for a few weeks, and make small data-driven adjustments. Consistency beats perfection every time.