Calculator
What the Weight Gain Calculator does
Weight Gain Calculator: calculates Weeks to Goal, Suggested Daily Calories and Daily Surplus from Current Weight, Goal Weight and Target Gain / Week. Example: current weight 60 kg, goal weight 68 kg and target gain / week 0.25 kg gives weeks to goal 32.0.
Give the Weight Gain Calculator your Current Weight, Goal Weight, Target Gain / Week and Daily Maintenance Calories and it works out Weeks to Goal, Suggested Daily Calories and Daily Surplus. There is no submit step; the numbers move as you adjust them.
It is mostly used by readers checking a number from a clinic. Knowing how a figure is derived makes it much easier to interpret sensibly.
Your measurements stay on your device. Health numbers are nobody else’s business, including ours.
The field table, the method and a worked example are documented after the tool for anyone who wants to check the working.
What do the Weight Gain Calculator fields mean?
The Weight Gain Calculator uses 4 inputs. Rather than an empty form you get a filled one, useful when you only want to test a single change.
| Field | What to enter | Default |
|---|---|---|
| Current Weight | measured in kg; accepts 30 to 300 | 60 |
| Goal Weight | measured in kg; accepts 30 to 300 | 68 |
| Target Gain / Week | measured in kg; accepts 0.1 to 1 | 0.25 |
| Daily Maintenance Calories | measured in kcal; accepts 1000 to 5000 | 2200 |
How does the Weight Gain Calculator work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same calculation.
Bad input produces a message, not a silently incorrect figure.
Worked example
These are the values the Weight Gain Calculator loads by default, and the result it produces from them. The defaults produce the result shown here; change any of them and the answer moves.
| Current Weight | 60 kg |
|---|---|
| Goal Weight | 68 kg |
| Target Gain / Week | 0.25 kg |
| Daily Maintenance Calories | 2200 kcal |
| Weeks to Goal | 32.0 |
|---|---|
| Suggested Daily Calories | 2,475 |
| Daily Surplus | 275 |
| Plan | Gaining 8.0 kg at 0.25 kg/week takes about 32 weeks. Try about 2475 kcal/day with progressive strength training. |
Read next: Understanding BMI: What the Number Measures, and What It Misses
How to use it
- Set Current Weight in kg (30 to 300).
- Put Goal Weight in kg (30 to 300).
- Key in Target Gain / Week in kg (0.1 to 1).
- Fill in Daily Maintenance Calories in kcal (1000 to 5000).
- Results update continuously rather than on submit.
- Check Weeks to Goal, Suggested Daily Calories, Daily Surplus and Plan on the right.
- If you need a record, Copy Link saves the inputs and Print produces a clean page.
What this tool does not do
- These formulas come from population averages and cannot account for your medical history.
- This is a screening estimate, not a diagnosis.
- It will not warn you that a different tool would suit your question better.
- The tool trusts your numbers completely, so a mis-keyed digit propagates straight through.
Frequently asked questions
Enter Current Weight in kg, Goal Weight in kg, Target Gain / Week in kg and Daily Maintenance Calories in kcal. Every input names its unit, and every output does too, which removes the usual source of error.
Current Weight accepts 30 to 300 kg. Go outside it and you get an error against that specific field instead of a misleading number.
With the values loaded when the page opens, weeks to goal comes out as 32.0. Edit any input and that figure moves with it.
No record is kept. We never receive what you type, so there is nothing on our side to retain.
No cost and no account. Use it as often as you like.
It is a screening estimate, not a diagnosis. The formulas are standard, but they describe averages and you are not an average. Use it as a starting point for a conversation with a professional.