Example Data Table
| Current Weight |
Height |
Calories |
Activity |
Days |
Estimated Loss |
| 90 kg |
170 cm |
1600 |
1.375 |
30 |
About 2.6 kg |
| 210 lb |
68 in |
1800 |
1.55 |
45 |
About 8.5 lb |
| 75 kg |
165 cm |
1450 |
1.2 |
60 |
About 3.1 kg |
Formula Used
BMR: 10 × weight kg + 6.25 × height cm - 5 × age + formula adjustment.
TDEE: BMR × activity factor.
Daily deficit: TDEE - planned daily calories.
Adjusted deficit: daily deficit × adherence percent.
Estimated weight loss: adjusted deficit × days ÷ 7700 for kilograms.
BMI: weight kg ÷ height meters squared.
The model uses energy balance. It does not model phentermine dose, drug response, appetite effects, side effects, or medical eligibility.
How To Use This Calculator
Choose your unit system first. Enter current weight, goal weight, height, age, activity, calories, days, and adherence. Optional log fields compare real progress with projected progress. Press calculate. The result appears below the header and above the form. Download the report as CSV or PDF for personal records.
Phentermine Weight Loss Planning With Energy Balance
A Physics Based View
A weight plan is easier to review when numbers are visible. This calculator uses a physics based energy model. It compares estimated daily energy use with planned food intake. The result is a projected change in body mass. The method is simple. It does not predict medicine response. It also does not replace care from a licensed clinician.
What The Calculator Measures
The tool starts with body weight, height, age, sex, activity level, calories, and time. It estimates basal metabolic rate. Then it multiplies that value by an activity factor. That gives an estimated total daily energy need. When calorie intake is lower than that need, the calculator shows an energy deficit. That deficit is converted into estimated weight loss.
Why Phentermine Needs Care
Phentermine is a prescription medicine. It may be used with diet, exercise, and medical follow up. People can respond differently. Heart rate, blood pressure, sleep, mood, and other factors may matter. For that reason, this calculator avoids dose advice. It only organizes weight, calories, BMI, and target dates. Share unusual symptoms or rapid changes with a professional.
Using Results Safely
Look at the weekly rate and the percent of body weight lost. Very fast loss can be risky. A modest pace is often easier to maintain. The projected number may differ from real progress because water, sodium, hormones, muscle, illness, and logging errors change scale weight. Use the log fields to compare planned loss with observed loss.
Better Planning Habits
Record weight at similar times. Use averages instead of one reading. Enter realistic activity. Update calories when your routine changes. Review BMI as a screening measure, not as a full health diagnosis. Combine the estimate with waist measures, strength, energy, and clinical guidance.
Final Notes
This calculator is best for planning conversations. It can show whether a target needs a large calorie deficit. It can also show if a goal date is aggressive. Use the exported report for records. Keep decisions about phentermine, dosage, duration, and stopping rules with your prescriber. When real results differ, adjust inputs slowly. Small changes are easier to sustain. Bring exported notes to visits, especially when appetite, sleep, or training changes over several weeks.
FAQs
1. Does this calculator tell me how much phentermine to take?
No. It does not provide dose, timing, duration, or stopping advice. Those decisions must come from a licensed prescriber who knows your medical history.
2. Is the weight loss projection guaranteed?
No. It is an estimate based on calories, activity, weight, height, age, and time. Water changes, logging errors, sleep, stress, and health factors can change real results.
3. Why is activity factor included?
Activity factor estimates daily energy use beyond resting metabolism. A higher factor raises estimated calorie needs. Choose the closest routine, not the most optimistic option.
4. What does adherence percent mean?
Adherence percent adjusts the planned calorie deficit. For example, 80 percent means the calculator counts 80 percent of the calculated daily deficit.
5. Can I use pounds and inches?
Yes. Select imperial units. The calculator converts pounds to kilograms and inches to centimeters before using the formulas.
6. Why does the tool show BMI?
BMI is a screening number based on weight and height. It is not a full health diagnosis. Use it with clinical advice and other body measurements.
7. What if estimated calories for goal are very low?
That may mean the target date is aggressive. Consider a longer timeline and discuss safe calorie limits with a qualified healthcare professional.
8. Can I download my results?
Yes. After calculation, use the CSV or PDF button. The download includes key estimates for review, tracking, or appointments.