Calculate 5% and 10% reductions from an adult starting weight. Optionally compare a latest weight and a personal target. See how the arithmetic works and when a clinician should help set the goal.
JavaScript is required to use the calculator. The guide and sources follow.
How to use it
- Choose kg or lb, then enter your starting weight. Number fields start empty.
- Optionally enter a latest weight and a personal target weight below your starting weight. Dates are optional and use YYYY-MM-DD.
- Calculate the two reference targets and review the difference and progress. Preview the summary before printing or saving it as a PDF.
Example
At a starting weight of 80 kg, 5% is 4 kg and the corresponding target is 76 kg. At 10%, the amount is 8 kg and the target is 72 kg. A latest weight of 77 kg is 3 kg or 3.75% below the starting value: 75% of the way to the 5% goal and 37.5% of the way to the 10% goal. These values appear only when you click “Fill example”; dates remain blank.
Equations and interpretation
Amount to lose = starting weight × 0.05 or × 0.10. Target weight = starting weight − amount. Change percent = (starting − latest) ÷ starting × 100. Progress toward the 5% or 10% reduction = change percent ÷ 5 or ÷ 10 × 100. A personal target uses (starting − personal target) as its goal amount. Negative progress means the latest weight is above the starting weight; a result over 100% means it is below the target.
The result is an arithmetic comparison, not a medical diagnosis, a recommended weight for everyone, or a forecast of when it will be reached. The NIDDK describes a 5%–10% reduction as an initial goal in suitable adults, often over about six months, with goals and monitoring tailored to the person. Do not infer a safe pace from this calculator.
When to ask for individual guidance
Do not apply adult weight-loss goals to children and adolescents, pregnancy or breastfeeding. If you are underweight, have an eating disorder history, or have a condition or medicine affecting weight, ask a clinician before choosing a goal. Record weight under similar conditions and consider other health indicators alongside it.
If you use a GLP-1 medicine, see Muscle Loss During GLP-1 Weight Loss for context on lean mass and function. Weight goals remain individual whether or not you take medicine.
Frequently asked questions
Can I use pounds?
Yes. Select lb and enter all weights in lb. The displayed results keep your selected unit.
Is a 10% target always better than 5%?
No. A goal depends on individual health, preferences and clinical context. These are reference calculations rather than a prescribed target.
How do I save the report as PDF?
Preview the result summary, choose Print / Save PDF, then select “Save as PDF” in your browser. The optional blank log starts on another page.
Related resources
Weight and waist log · Health records · Adult BMI calculator · Waist-to-height ratio calculator · BMR and TDEE calculator · Lab results guide
Sources
- NIDDK: Choosing a safe and successful weight-loss program
- NIDDK: Treatment for overweight and obesity
- CDC: Steps for losing weight
Sources checked 2026-09-30 · General information, not a substitute for care. No independent clinician review is claimed.