How this tool works
This calculator estimates how many calories a day you may need to keep your current weight. It is a starting estimate, not a diet or a weight-loss plan.
You enter your sex, age, height, weight and usual activity level. The tool converts pounds to kilograms (dividing by 2.2) and inches to centimeters (multiplying by 2.54). It then uses the Mifflin–St Jeor equation to estimate your basal metabolic rate (BMR), the energy your body uses at rest:
- Men: BMR = 10 × kg + 6.25 × cm − 5 × age + 5
- Women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161
Your BMR is multiplied by an activity factor to give your estimated maintenance calories:
| Activity level | Factor |
|---|---|
| Sedentary (little or no exercise) | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
Finally, the tool shows your result next to the Dietary Guidelines for Americans estimates for adults 61 and older: about 1,600 (sedentary) to 2,000 (active) calories a day for women, and about 2,000 (sedentary) to 2,600 (active) for men.
A worked example
A 68-year-old woman is 5 feet 4 inches tall (64 inches), weighs 150 pounds and is lightly active.
- Weight: 150 ÷ 2.2 = about 68.2 kg
- Height: 64 × 2.54 = about 162.6 cm
- BMR: (10 × 68.2) + (6.25 × 162.6) − (5 × 68) − 161 = 682 + 1,016 − 340 − 161 = about 1,197
- Maintenance: 1,197 × 1.375 = about 1,646 calories a day
That sits inside the 1,600 to 2,000 range the Dietary Guidelines give for women 61 and older.
Limits of this tool
Equations like Mifflin–St Jeor give an average estimate. Real needs vary with muscle mass, health conditions, medicines and how active you truly are. It is easy to pick an activity level that is a little too high. The tool also does not tell you what to eat. Calories are only part of the picture; protein, fluids, calcium and vitamin D matter too. Our protein calculator and calcium and vitamin D calculator can help with those.
When to talk to your doctor
Speak with your doctor before cutting calories, especially if you have diabetes, heart or kidney disease, or take medicines that interact with food. Call your doctor if you are losing weight without trying or have lost your appetite. A doctor can also refer you for nutrition therapy if you have diabetes or kidney disease, which Medicare Part B covers.
Frequently asked questions
Why does age lower the estimate?
The equation subtracts 5 calories for each year of age. This reflects the general pattern that resting energy needs tend to fall as people get older.
Can I use this to lose weight?
This tool only estimates maintenance calories. Weight loss in older adults should be planned with a doctor, since losing muscle along with fat can affect strength and balance.
Which activity level should I choose?
Pick the one that matches a typical week, not your best week. If you are unsure, choosing the lower level gives a more cautious estimate.
My result is outside the Dietary Guidelines range. Is that a problem?
Not necessarily. The guideline ranges are broad averages. Your size and activity can put you above or below them. Share the result with your doctor if you have questions.
Sources
Want the full picture? Read our guide: Protein for Seniors: How Much You Need and Easy Ways to Get It.
Read the guideThis tool gives general information for education only. It does not diagnose any condition or replace advice from your doctor, nurse or pharmacist. In an emergency call 911. See our medical disclaimer and sources.