When you just want a ballpark number, multiplying weight by an activity factor is surprisingly close to the full equations for most adults of average build.
How to use the Simple Calorie Intake Calculator
- Weight
- Activity level
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter your weight and pick your activity level. Subtract about 500 kcal from the result to lose about 1 lb (0.45 kg) a week.
Inputs explained
| Field | What to enter |
|---|---|
| Weight | Units: kg, lb, st, g |
| Activity level | Choose one: Sedentary (13 kcal/lb), Lightly active (14 kcal/lb), Moderately active (15 kcal/lb), Active (16.5 kcal/lb) … |
What each result means
- Daily calories to maintain = [Weight]÷0.45359237×[Activity level]
- Daily calories to lose ~0.5 kg (1 lb) a week = [Daily calories to maintain] – 500
- Daily calories to gain ~0.25 kg a week = [Daily calories to maintain] + 250
Example values
How the main result changes when Weight changes and everything else stays at the example values above:
| Weight (kg) | Daily calories to maintain (kcal/day) |
|---|---|
| 37.5 | 1,240 |
| 56.25 | 1,860 |
| 75 | 2,480 |
| 93.75 | 3,100 |
| 112.5 | 3,720 |
| 150 | 4,960 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Calories = weight (lb) × factor
Sedentary 13 · lightly active 14 · moderately active 15 · active 16.5 · very active 18
Worked example
Inputs — Weight: 75 kg; Activity level: Moderately active (15 kcal/lb).
Results — Daily calories to maintain = 2,480 kcal/day; Daily calories to lose ~0.5 kg (1 lb) a week = 1,980 kcal/day; Daily calories to gain ~0.25 kg a week = 2,730 kcal/day.
Key terms
- kcal/lb
- Calories per pound of body weight.
Frequently asked questions
Is this as accurate as BMR equations?
It is less precise because it ignores age, height and sex, but it is a useful quick check.
Why does weight drive calories?
Bigger bodies need more energy to function and move.
Can I use goal weight instead?
Using goal weight gives a lower, more conservative target.