Maintenance calories are your daily energy use; estimate with RMR × activity, then refine using 2–4 weeks of weight-trend data.
If you want a number you can use today, you can get there in two passes. First, estimate resting burn with a research-backed formula. Next, scale that number to match how much you move. Then you watch the scale trend and adjust. This page shows the math, the shortcuts, and a simple way to sanity-check the result against official ranges.
How To Calculate Your Maintenance Calorie Number
You’ll start with resting metabolic rate (RMR). The Mifflin–St Jeor equation predicts how many calories you burn at rest from age, height, weight, and sex. It’s widely used in dietetics because it tracks measured values well in healthy adults. After you have RMR, multiply by an activity factor that matches your week. The product is a practical total daily energy expenditure (TDEE).
Step 1: Find RMR With The Mifflin–St Jeor Formula
Men: RMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) + 5
Women: RMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) − 161
Convert pounds to kilograms (lb ÷ 2.205) and inches to centimeters (in × 2.54). The result is your resting burn before daily movement and exercise.
Step 2: Pick A Week-Match Activity Factor
Choose the line that fits your weekday pattern. If your weeks vary, use the one that matches the current week, then update when your routine changes.
| Activity Level | Typical Week | Multiplier |
|---|---|---|
| Sedentary | Desk work, few purposeful steps or workouts | 1.2 |
| Lightly Active | Desk work plus 30–60 min light movement most days | 1.35 |
| Moderately Active | 1–3 h moderate exercise per week or 8–12k steps/day | 1.55 |
| Very Active | 4–6 h hard training per week or active job | 1.75 |
| Extra Active | Manual labor or 2-a-day training blocks | 1.95 |
TDEE = RMR × activity factor. That number is your starting maintenance target. It won’t be perfect, but it puts you within striking distance for most adults.
Quick Example Math You Can Copy
Say a 30-year-old woman weighs 70 kg and is 165 cm. RMR = 10×70 + 6.25×165 − 5×30 − 161 = 700 + 1031 − 150 − 161 = 1,420 kcal. If her weeks include three brisk walks and two short lifts, “Moderately Active” fits: 1,420 × 1.55 ≈ 2,201 kcal. That’s the working daily target to hold weight.
Reality Check Against Official Ranges
Sanity-check your math with published ranges. The Dietary Guidelines’ estimated calorie tables list daily needs by age, sex, and activity. Your personal number can sit above or below a row, but it shouldn’t be wildly off. If it is, recheck units, age, and the activity choice.
Dialing It In With Your Trend
Your body isn’t a spreadsheet. Sleep, hormones, step counts, and training load move the needle day to day. So you tighten the estimate with real data from the next two to four weeks.
Set Up A Simple Watch List
- Weigh yourself at the same time each morning after using the bathroom.
- Log calories eaten with any reliable tracker.
- Note steps or workouts so your activity factor choice stays honest.
Make Small, Timed Adjustments
If your 7-day average weight drifts up, trim 100–150 kcal and watch another 7–14 days. If it drifts down, add 100–150 kcal. Large swings hide true trends, so keep changes steady and give them time to show.
Why This Method Works
The Mifflin–St Jeor formula has a strong track record in healthy adults across body sizes. It often beats older equations when compared with indirect calorimetry. Then the activity factor stitches in daily movement, giving a workable total. The final polish comes from your progress log, turning a decent estimate into a personal fit.
Use A Trusted Calculator When You Want Speed
If you prefer a vetted tool, the NIH’s Body Weight Planner lets you set a goal and returns calorie targets to reach and hold that weight. It models how bodies adapt across weeks, which helps keep plans grounded.
Common Pitfalls That Throw Off The Number
Rounding Errors And Unit Mix-ups
Swapping pounds for kilograms or rounding height too far can swing the result. Keep one decimal place on weight and height when you run the math.
Mismatch Between Activity Label And Week
Many people pick “Very Active” when their step count suggests the tier below. Cross-check with your wearable or a pedometer for a week.
Weekend Swings
Large calorie surges on two days can erase five tidy weekdays. If your weight trend bounces, look at weekend intake and steps first.
Sample Targets For Different Body Sizes
These examples use the RMR formula and the activity factors above. They’re starting points, not fixed prescriptions. Adjust with your scale trend and how you feel during training and daily life.
| Profile | Activity | Start Target (kcal) |
|---|---|---|
| Woman, 60 kg, 165 cm, 35 y | Lightly Active | ~1,900 |
| Woman, 75 kg, 170 cm, 28 y | Moderately Active | ~2,250 |
| Man, 70 kg, 175 cm, 40 y | Sedentary | ~1,950 |
| Man, 85 kg, 180 cm, 32 y | Very Active | ~2,900 |
| Man, 100 kg, 185 cm, 45 y | Moderately Active | ~2,850 |
How To Adjust When Goals Change
If You’re Trying To Lose Fat
Start by trimming 300–400 kcal from the maintenance target or by adding a brisk 40-minute walk most days. Keep protein high, lift 2–3 times a week, and track the 14-day trend. If the average isn’t budging after two weeks, make another small nudge.
If You’re Aiming To Gain Muscle
Add 200–300 kcal and keep a progressive strength plan. Watch that your weekly average rises about 0.25–0.5% of body weight. If appetite is low, increase calorie-dense whole foods and space meals through the day.
Activity Examples You Can Map To The Factors
Use these real-world anchors to choose a factor with more confidence:
Sedentary
Office job, short commute, fewer than 6,000 steps most days, no workouts.
Lightly Active
7,000–9,000 steps most days, short home circuits, or leisurely cycling once or twice a week.
Moderately Active
10,000–12,000 steps, three moderate workouts, or regular brisk walking.
Very Active
High step counts plus frequent intense training sessions or a physically demanding job.
Extra Active
Two training blocks a day or heavy manual work layered on top of long days on your feet.
How To Handle Mixed Weeks
Busy season at work, travel, or a new program can change movement fast. Pick the factor that reflects the current seven days, not your “ideal” week. Re-run the math next week if your schedule flips.
What If The Estimate Still Feels Off?
If hunger, training performance, and sleep are worse on the target you chose, shift by 100–150 kcal and recheck the 7-day average. Energy levels and recovery matter along with the scale trend.
Simple Checklist To Lock It In
- Run the RMR math with the right units.
- Pick the activity factor that matches this week.
- Start with the product as your daily target.
- Track intake and a 7-day weight average.
- Adjust in 100–150 kcal steps every 1–2 weeks.
Method And Sources
The RMR equation above comes from research by Mifflin and St Jeor (1990), which compared predictions with indirect calorimetry in healthy adults. The activity tiers mirror public-health guidance that groups movement into light, moderate, and vigorous ranges. For fast planning, the Dietary Guidelines include estimated calories by age, sex, and activity, and the NIH’s Body Weight Planner offers a validated tool for setting and holding targets.