Free tool for nutritionists
Weight path calculator
When a client reaches their goal weight on the calories they eat, or where their weight levels off first, with their TDEE on the way.
About the client
How active they are
Their goal, and calories a day
No goal yet? Leave it empty to see where their weight levels off.
Calories fill in with a suggested target once the client and their activity are in.
How the path is worked out
It runs the TDEE RegimePlan suggests targets from forward, a day at a time, in four steps.
1. TDEE today
The Mifflin-St Jeor equation gives the calories the body burns at rest (BMR) from weight, height, age and sex. An activity multiplier turns it into TDEE, the calories burned in a day. The macro calculator shows both steps in full.
2. The gap moves the weight
Each day, the gap between the calories eaten and TDEE moves the weight by the gap divided by 7,700 kcal per kg. A 375 kcal daily deficit takes off about 0.34 kg a week to begin with.
3. TDEE follows the weight
BMR carries 10 kcal for each kilo, so each kilo lost takes 10 × the activity multiplier off TDEE. The same calories make a smaller gap every week, and the weight slows as it nears the weight at which TDEE equals the calories.
| Activity | Multiplier | TDEE per kg |
|---|---|---|
| Sedentary | × 1.2 | 12 kcal |
| Lightly active | × 1.375 | 13.75 kcal |
| Moderately active | × 1.55 | 15.5 kcal |
| Very active | × 1.725 | 17.25 kcal |
| Extra active | × 1.9 | 19 kcal |
4. Where the path ends
The path stops at whichever comes first:
- The goal weight, when the calories move the weight towards it.
- A plateau, the day the gap falls under 100 kcal a day: less than half a kilo a month, too little for a scale to tell from water.
- BMI 18.5, when a deficit would take the client under it first. The path stops there with a warning.
The suggested calories
Until you change them, the calories are the target RegimePlan suggests for the goal: 375 kcal under TDEE to lose, 375 over it to gain, and TDEE with no goal. A loss never goes below 1,200 kcal a day for women or 1,500 kcal for men.
A worked example
A 34-year-old woman, 165 cm and 82 kg, lightly active, with a goal of 70 kg:
- TDEE: 1,520 × 1.375 = 2,090 kcal
- Suggested calories: 2,090 − 375 = 1,715 kcal
- She reaches 70 kg in about 11 months, losing 1.4 kg in the first month and 0.9 kg in the last.
- At 70 kg her TDEE is 1,925 kcal: about what holds her there.
Equations describe an average adult, and the body also burns a little less as it loses weight, which this path leaves out. Treat it as a guide and adjust with the weigh-ins. Pregnancy, breastfeeding and health conditions need a professional's advice.
Questions about weight paths
Why does weight loss slow down on the same calories?
A lighter body burns less. Each kilo lost takes 12–19 kcal off TDEE, depending on activity, so a deficit that starts at 400 kcal shrinks a little every week. The weight keeps falling, more slowly, until TDEE meets the calories.
What counts as a plateau here?
The day the gap between TDEE and the calories falls under 100 kcal a day. From then on the client loses less than half a kilo a month, which water and food weight hide on the scale.
How long will my client take to reach their goal weight?
Enter the client, their activity, their goal and the calories they eat, and the calculator gives the months. The first months move fastest, and the last kilos before the goal take longest.
Does the metabolism slow down more than this?
Often it does. After weeks in a deficit, people tend to move a little less and burn a little less than the equations predict. This path leaves that out, so a real plateau can come sooner and a little higher. Weigh-ins every week or two show which way the client is going.
Why does the path stop at BMI 18.5?
BMI 18.5 is where underweight starts. A deep deficit kept for months would take some clients below it before their weight levels off, so the calculator stops there and says so instead of drawing the rest.
Where do the suggested calories come from?
From the targets RegimePlan suggests when a client joins: TDEE minus 375 kcal to lose, plus 375 to gain, never below 1,200 kcal for women or 1,500 for men. Change them to what the client eats now to see where that leads.
Can I follow this for every client?
Yes. RegimePlan keeps each client's weigh-ins, targets and meal plan in one place, so you see a slowdown coming and adjust the plan in time. It's free for up to 3 active clients.
Plan every client's path to their goal
RegimePlan tracks each client's weigh-ins against their plan, so you can adjust their targets before they stall. Free for up to 3 active clients.
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