- Enter current and target weight
Use the same unit for both values.
- Choose a weekly rate
Select a pace that fits your plan and professional advice.
- Review the energy assumption
The default is a rough planning conversion and can be changed.
- Read the timeline
The calculator shows weight difference, estimated weeks, and daily surplus.
- Adjust from actual results
Use several weeks of trend data rather than reacting to daily fluctuations.
Weight Gain Calculator
The Weight Gain Calculator estimates how long it may take to reach a higher target weight at a chosen weekly rate. It also converts that rate into an approximate daily energy surplus using a user-adjustable energy-per-kilogram assumption.
Real body-weight change is not perfectly linear. Water, glycogen, digestion, training status, medication, illness, and changes in energy expenditure can all shift the scale independently of tissue gain.
Calculator inputs
kg
kg
kg
kcal
Result
—
Estimated time to target
Weight to gain—
Estimated duration—
Daily surplus—
Weight to gain = Target weight − Current weight
Estimated weeks = Weight to gain ÷ Weekly gain
Daily energy surplus = Weekly gain × Energy per kg ÷ 7
What the result means
Actual needs should be adjusted using observed weight trends and health guidance.
Results are estimates based on the values and assumptions entered.
Given: Current weight 70 kg, target 75 kg, weekly gain 0.25 kg, and 7,700 kcal per kg.
Calculation: 5 ÷ 0.25 = 20 weeks; 0.25 × 7,700 ÷ 7 = 275 kcal/day.
Result: 20 weeks and about 275 kcal/day.
Actual needs should be adjusted using observed weight trends and health guidance.
Is the calorie conversion exact?
No. It is a planning assumption; body-weight change is not a fixed calorie conversion.
Can I enter pounds?
The current page is labeled in kilograms. Convert both weights and use a matching energy assumption if using another unit.
Why does weight fluctuate daily?
Water, sodium, glycogen, food mass, and hormones can move scale weight independently of tissue gain.
Should the weekly rate stay constant?
Not necessarily. Review the trend and adjust with qualified guidance.
Does this replace nutrition advice?
No. Medical conditions and individual nutrition needs require professional advice.