Weight Loss Calculator

Weight loss calculator 2026 online. TDEE, deficit and time to target

The following description is a complete guide to the Livewire "Weight Loss Calculator" addon. Here you will find the logic of the algorithm, the justification for the thresholds, an instruction manual, step-by-step examples, a scenario table, a security section, and implementation notes for developers. The description remains consistent with the component class and view you passed in the zip package.

What the calculator calculates and who it is intended for

The calculator answers three practical questions. First, how muchTDEE(total daily energy requirement) you need for a given activity level. Second,what calorie deficitis consistent with your chosen weight loss rate. Third,how many weeksit will take to get down from your current weight to your goal weight at a given pace. The tool is useful for people losing weight, trainers preparing quick recommendations and dietitians who need a quick look at the numbers while maintaining reasonable safety limits.

Input data and validation

The form takes into account anthropometric parameters and lifestyle, and the validation protects the limits of values. Ranges and allowable choices:

• Gender: maleorfemale.
• Age: integer10–120years.
• Height: 80–250cm (0.1 cm steps in view).
• Weight: 20–400kg (0.1 kg steps).
• Target weight: 20–400kg.
• Activity(factor): one of the values ​​of1.2, 1.375, 1.55, 1.725, 1.9as described in the interface. Validation generally allows1.0–2.5, but the view guides the user to real presets.
• Weight loss rate (kg/week): exactly one of the values0.25, 0.5, 0.75, 1.0.

Interface contains buttonsCalculate i Clear, and the results are displayed in four tabs:TDEE, Deficit, Suggested Supply, Weeks to Goal. The note below the results explains the basics: the Harris-Benedict formula and the assumption1 kg of fat ≈ 7700 kcal.

Algorithm. Where do the

numbers come from? The calculation logic consists of three steps: BMR, TDEE, deficit and time. Patterns and thresholds are consistent with the addon code.

User instructions

1. Select gender, enter age, height and current weight.
2. Enter target weight. For reduction it should be lower than the current one.
3. Choose the activity level that best reflects your week.
4. Select your weight loss rate. Start with 0.25 or 0.5 kg/week if you have no contraindications.
5. ClickCalculateand read TDEE, deficit, suggested supply and weeks to target.
6. If the supply falls below 800 kcal, the calculator will apply the safety floor.

Extended calculation examples

Sedentary person, female 30 years old, 165 cm, 72 kg → target 64 kg, pace 0.5 kg/week, activity 1.375

BMR ≈447.593 + 9.247×72 + 3.098×165 − 4.330×30≈ 1491 kcal.
TDEE ≈1491 × 1.375≈ 2050 kcal.
Deficit for 0.5 kg/week:(0.5×7700)/7≈ 550 kcal/day.
Suggested supply ≈2050 − 550= 1500 kcal/day.
Mass difference:72 − 64 = 8kg. Time ≈8/0.5= 16 weeks.

Male 40 years old, 180 cm, 95 kg → target 85 kg, pace 0.75 kg/week, activity 1.55

BMR ≈88.362 + 13.397×95 + 4.799×180 − 5.677×40≈ 1908 kcal.
TDEE ≈1908 × 1.55≈ 2957 kcal.
Deficit:(0.75×7700)/7≈ 825 kcal/day.
Supply ≈2957 − 825= 2132 kcal/day.
Mass difference:95 − 85 = 10kg. Time ≈10/0.75≈ 13.3 weeks.

Woman 24 years old, 170 cm, 62 kg → target 60 kg, pace 0.25 kg/week, activity 1.55

BMR ≈447.593 + 9.247×62 + 3.098×170 − 4.330×24≈ 1474 kcal.
TDEE ≈1474 × 1.55≈ 2285 kcal.
Deficit:(0.25×7700)/7≈ 275 kcal/day.
Supply ≈2285 − 275= 2010 kcal/day.
Mass difference:62 − 60 = 2kg. Time ≈2/0.25= 8 weeks.

Extended indicative table

Practical tips for reduction

• Choose your activity realistically. The overestimation understates the deficit.
• At a rate of 0.75–1.0 kg/week. the risk of low supply and worse tolerance increases. Consider 0.5 kg/week. as a compromise.
• Do not lower your intake below 800 kcal. It's a hard floor in the tool.
• A comfortable start is 0.25–0.5 kg/week. and activity 1.375–1.55.
• Include days off from training. TDEE is calculated from a weekly pattern.

Frequently asked questions and answers

Is the pace of 1.0 kg/week is for everyone

No. This is an aggressive pace that requires a high deficit and good tolerance. In many cases, 0.5 kg/week is more reasonable.

What if the target weight is higher than the current

The tool calculates the reduction. When the goal is ≥ current weight, the difference is 0 and the time score is 0 weeks. There is no reason to use a deficit.

Why was 7,700 kcal per 1 kg

This is an approximation of the energy stored in a kilogram of fat tissue. Treat the results as indicative. In practice, the body's reaction varies.

Does the calculator take into account metabolic adaptations

No. It's a deterministic model. Metabolic adaptations during longer reductions may lower TDEE relative to the baseline.

Most common mistakes and ways of correction

• Too high activity in the selection→ choose a lower preset if your work is sedentary and your training is sporadic.
• Aggressive pace without observing tolerance→ start with 0.5 kg/week. and assess energy, sleep, recovery.
• No parameter update→ after a 5-10% weight loss, recalculate the parameters because the TDEE will change.
• Taking the supply below the fuse→ the tool holds a minimum of 800 kcal, do not go lower in the real plan.

Implementation in the project. Developer Notes

The Livewire componentWeight Loss Calculatorprovides public properties:gender, age, height, weight, target, activity, rate, as well as the resultstdee, deficit, intake, weeks. Thecalculate()method validates inputs, calculates BMR according to Harris-Benedict, converts TDEE by activity factor, deficit from pace and weeks to goal from mass difference. The caloric intake has a minimum floor of 800 kcal. Results are cast to ints and weeks to one decimal place.

History:saveHistory()method is protectedtry/catch. With the presence of a modelApp\Models\Admin\Historysaves a lightweight record with input and output metadata, IP address and timestamp. Missing model does not break and is logged withLog::error(...).

Technical Tips

• Validation in the component: age, height, weight, activity and allowed pace ranges according to the rules.
• Maintain consistent number format and decimal separator in the view.
• The description of the activity presets comes from translations: from sedentary to very high activity.
• Buttons pinned to methodscalculate i resetForm. Reset restores default values ​​and clears results.
• Results only displayed if$tdeeis set.

Extended test scenarios

Interface communication. Microcopy

• Result description:TDEE, deficit, supply and time are indicative values ​​. The model does not replace medical advice.
• Tip:Choose an activity that best reflects your week.
• Reminder:Update parameters regularly after a 5-10% drop in weight.

Safety and responsible use

Calculate your TDEE and the deficit now