Weight Loss Calculator

How to use this weight loss exercise planner

What this calculator does

This calculator estimates how a planned exercise routine contributes to the energy gap associated with a chosen weight-loss pace. It combines a simple planning assumption of 7,700 kilocalories per kilogram of body-weight change with activity energy expenditure estimated from metabolic equivalents, or METs. The result is a target timeline, an exercise-only pace, and an estimate of any remaining daily deficit implied by your selected pace. It does not predict your exact biological response, resting metabolism, appetite adaptation, body composition, or medical suitability. For a dynamic physiological model, the NIDDK Body Weight Planner provides a more detailed adult weight-planning framework.

When to use it

Use the planner when you want to compare a walking, cycling, running, swimming, yoga, calisthenics, or stationary-bike routine against a specific weekly weight-loss pace; when you know your available exercise time and want to compare activities on the same schedule; when you want to see how much of a planned energy gap could come from structured exercise; or when you want a week-by-week planning table to discuss with a qualified health professional or coach.

How to calculate

1. The calculator opens with a ready-to-use example: 85 kg current weight, 75 kg target weight, 0.50 kg/week pace, moderate walking at 3.8 MET, 45 minutes per session, and 5 sessions per week. The example XLSX is immediately available.
2. Replace Current weight and Target weight. Use Weight unit to switch between kilograms and pounds; both weight values are converted automatically.
3. Choose Weight loss pace. This drives the target timeline and weekly target energy gap. Then choose Planning approach. “I know my activity” uses the selected Activity; “I know my available time” emphasizes the activity-comparison table for the same schedule.
4. Enter Exercise time in active minutes per session and Sessions as a whole number per week. Results and tables update live.
5. Read the target timeline together with the exercise-only pace. If Additional daily deficit is above zero, the chosen routine alone is below the energy gap implied by the selected pace. A zero value means the estimated exercise expenditure is at least as large as that planning gap; it is not a recommendation to exercise more or eat less.
6. Select Download Excel to create a fresh workbook from the current validated inputs. Reset clears the demonstration data and calculated state; Download Excel then stays disabled until a complete valid plan is entered again.

Input guide

Current weight is required and accepts a positive decimal number using a period as the decimal separator, with optional standard comma thousands grouping; for example, 85 kg. It must be no more than the 500 kg equivalent supported by this planner. A higher weight increases MET-based calorie expenditure for the same activity and time. Scientific notation and ambiguous decimal-comma entries are rejected. Target weight is required, uses the same format and unit, and must be lower than current weight; 75 kg is the example. The difference between current and target weight determines the total planned energy gap.

Weight unit is required and offers kg or lb. Changing it converts both weight fields without changing the underlying canonical kilogram model. Weight loss pace is required and offers 0.25, 0.50, 0.75, or 1.00 kg/week equivalents; 0.50 kg/week is the example. The CDC notes that gradual, steady weight loss of about 1 to 2 pounds per week is more likely to be maintained than faster loss, but individual circumstances vary.

Planning approach is required. “I know my activity” uses the chosen Activity for the highlighted exercise results, while “I know my available time” keeps the same minutes and sessions but shifts attention to the comparison table. Activity is a fixed list of representative adult activities with MET values; moderate walking at 3.8 MET is the example. MET is an energy-cost index, and the 2024 Adult Compendium of Physical Activities is the source basis for the listed values. MET estimates describe typical energy cost, not an individual measurement.

Exercise time is required, accepts a positive decimal number of active minutes per session, and is limited to 1 – 1,440 minutes; 45 minutes is the example. Longer sessions increase estimated exercise calories linearly. Sessions is required, accepts a whole number from 1 to 21 per week, and is 5 in the example. More sessions increase weekly exercise calories linearly. Entering partial sessions, zero, negative values, or unsupported symbols produces a visible validation error.

Output guide

Target timeline is the weight to lose divided by the selected pace, expressed in weeks. Total energy gap is the weight difference multiplied by 7,700 kcal/kg. Calories per session uses the MET equation with current body weight and session duration. Weekly exercise calories multiplies the session estimate by sessions per week. Exercise-only pace converts those weekly exercise calories back to an equivalent kg/week using the same 7,700 kcal/kg planning assumption. Exercise-only timeline divides the total energy gap by weekly exercise calories. Additional daily deficit is the positive remainder between the selected weekly pace gap and estimated exercise calories, divided by seven. These are estimates and planning identities, not prescriptions.

The summary pills repeat weight to lose, target weeks, weekly exercise calories, and exercise-only pace from the same canonical model. The Activity comparison table lists each activity, MET, calories per session, calories per week, exercise-only pace, and exercise-only timeline for your current schedule. The Target plan projection table lists week, planned weight, cumulative target deficit, exercise contribution, and the remaining other deficit needed under the selected pace. If the target is reached during a partial final week, the last row is capped exactly at the target weight and total planned energy gap.

Worked example

With the startup values, the goal is 85 – 75 = 10.00 kg. At 0.50 kg/week, the target timeline is 10 ÷ 0.50 = 20.0 weeks and the simple total energy gap is 10 × 7,700 = 77,000 kcal. Moderate walking at 3.8 MET and 85 kg uses the standard estimate 3.8 × 3.5 × 85 ÷ 200 = 5.6525 kcal/min. Over 45 minutes, that is about 254 kcal per session; five sessions produce about 1,272 kcal/week. Dividing by 7,700 gives an exercise-only pace of about 0.17 kg/week and an exercise-only timeline of about 60.5 weeks. The 0.50 kg/week target implies 3,850 kcal/week, leaving about 2,578 kcal/week, or 368 kcal/day, not supplied by the selected walking schedule.