Set a realistic goal weight in steps. Use the healthy BMI range (18.5 to under 25) only as a rough guide, then aim first for about 5 % of your current weight, lost at about 0.5–1 kg a week. Reach it, hold it, then reassess. Under 18 or with an eating disorder history, talk to a doctor first.
Key takeaways
- BMI is a rough screening tool; at 1.70 m the healthy range spans almost 19 kg.
- A first goal of about 5 % of your weight is reachable and, per the CDC, can already improve health markers.
- At about 0.5 kg a week, losing 4.5 kg takes roughly 9 weeks on paper.
- Never plan below about 1,200 kcal (women) or 1,500 kcal (men) a day without medical supervision.
- Under 18, pregnant or with an eating disorder history, set any goal with a doctor.
What makes a goal weight realistic?
A realistic goal weight is one you can reach at a steady pace while still eating enough to feel well, and then keep. It is less about a "perfect" number and more about three practical questions: is the target within a healthy range for your height, can you get there without extreme restriction, and can you picture living at that weight with your normal work, family life and food culture?
Many people pick a goal from memory ("what I weighed at 20"), from someone else's body or from a round number. None of those are wrong as wishes, but they say nothing about your current health, muscle mass or routine. A more useful approach is to set a first milestone that is clearly achievable, reach it, and only then decide whether a further goal makes sense.
How can BMI help you choose a range?
Body mass index (BMI) is your weight in kilograms divided by your height in metres squared. It is a rough screening tool, not a diagnosis. For adults aged 20 and over, the WHO and CDC use these categories:
| BMI (kg/m²) | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 to under 25 | Healthy weight |
| 25 to under 30 | Overweight |
| 30 or above | Obesity |
To turn this into weights, multiply your height in metres by itself, then by 18.5 and by 25. For someone 1.70 m tall, 1.70 × 1.70 = 2.89, so the healthy-weight band runs from about 53.5 kg to just under 72.3 kg. That is a range of almost 19 kg, which is the point: there is no single "correct" weight for a height.
BMI has clear limits. It does not distinguish fat from muscle or bone, and it does not show where fat is carried. Someone with a lot of muscle can have a high BMI without excess fat, and the CDC notes that BMI should be considered together with other factors such as blood pressure and cholesterol. The WHO also mentions waist circumference as another measure. Use BMI to see roughly where you are, not to pick an exact number.
Why start with a first goal of about 5 %?
You do not have to reach the middle of the healthy range to benefit. According to the CDC, even modest weight loss can help improve blood pressure, cholesterol and blood sugar levels. Its own example is a 5 % reduction: 10 lb for a person who weighs 200 lb.
A 5 % first goal is concrete and reachable. Here is what it looks like, with the time it would take at about 0.5 kg per week:
| Starting weight | 5 % goal | New weight | Time at ~0.5 kg/week |
|---|---|---|---|
| 70 kg | 3.5 kg | 66.5 kg | about 7 weeks |
| 90 kg | 4.5 kg | 85.5 kg | about 9 weeks |
| 110 kg | 5.5 kg | 104.5 kg | about 11 weeks |
These are estimates on paper; real progress is rarely a straight line. Once you reach the first milestone, you can hold it for a while, check how you feel, and set the next step. Several small goals are easier to sustain than one large one, and every milestone you keep counts.
How long should it take to reach your goal?
Health agencies including the CDC describe a gradual loss of about 0.5–1 kg (1–2 lb) per week as realistic for adults, and people who lose weight at that pace are more likely to keep it off. To estimate your timeline, divide the total you want to lose by your weekly pace. For example, 10 kg at 0.5 kg per week is about 20 weeks; at 1 kg per week, about 10 weeks.
Expect the pace to slow as you get closer. A smaller body needs less energy, so the same intake creates a smaller deficit over time. Near the goal, 0.25–0.5 kg a week is often more realistic. Our guide on how fast you can safely lose weight explains the pace options in more detail, and the NIH Body Weight Planner can model how your timeline changes as your weight drops.
How do you turn the goal into a daily calorie target?
A widely used rule of thumb says that about 7,700 kcal corresponds to 1 kg of body fat. It is approximate, but it is useful for planning: 0.5 kg per week means a weekly deficit of about 3,850 kcal, or roughly 550 kcal a day below your maintenance calories. If calorie deficits are new to you, start there.
Whatever your goal, your daily intake should not drop below about 1,200 kcal for women or 1,500 kcal for men without medical supervision. If your timeline only works below those numbers, the timeline needs to change, not the floor. You can estimate your own target with the calculator below.
Daily calorie calculator
Mifflin-St Jeor equation × activity factor. Capped at the usual minimum (1,200 kcal women / 1,500 kcal men); going lower needs medical supervision. Estimates only.
In Sporty you enter your goal weight once, and the app uses it with your age, height and activity level to set a daily calorie target that you can adjust later.
Should your goal be only a number on the scale?
The scale is one signal among several. Daily weight can move by a kilo or more because of water, salt, carbohydrates and digestion, so a single weigh-in says little. A weekly average is more reliable; see water weight vs fat loss for how to read it.
It also helps to pair the weight goal with goals you control directly:
- Eating habits: a protein source at each meal, vegetables at lunch and dinner, fewer sugary drinks.
- Movement: a daily step target or two or three sessions of activity you enjoy each week.
- Other measures: waist measurement, how your clothes fit, energy, sleep and blood test results your doctor tracks.
These goals keep you moving forward in weeks when the scale stays still.
What if you stop losing weight before your goal?
Plateaus are common. Often the reason is that maintenance calories fall as weight falls, or that portions have slowly grown. Check your intake honestly for a week or two, recalculate your target for your current weight and give it time; our article on the weight loss plateau covers the options.
It is also worth asking whether the original goal still fits. If you have been stable for months at a weight that is in or near the healthy range, eating well and feeling good, maintaining that weight is a valid and realistic goal in its own right. Keeping weight off is a skill, and it deserves as much attention as losing it.
When should you set a goal with a doctor?
The information here is general and is not medical advice. Talk to a doctor or registered dietitian before setting a weight-loss goal if any of these apply:
- You are under 18. Children and teenagers are assessed with age- and sex-specific growth references, not adult BMI categories, and growing bodies have different needs.
- You have, or have had, an eating disorder, or you notice that thoughts about food and weight are taking over your day.
- Your BMI is already below 18.5, or your goal would put it there.
- You are pregnant or breastfeeding, have diabetes, kidney disease or another medical condition, or take medication that affects weight or appetite.
- You are an older adult, where keeping muscle and strength may matter more than the number on the scale.
A good goal weight should make your life easier and healthier, not narrower. If chasing a number starts to feel like the opposite, it is a sign to step back and get support.
Frequently asked questions
How do I calculate my healthy weight range?
Square your height in metres and multiply by 18.5 and by 25. For 1.70 m that gives about 53.5 kg to just under 72.3 kg. BMI is only a rough screening tool, so treat it as a range, not a target.
Is a 5 % weight loss worth it?
According to the CDC, even modest weight loss can help improve blood pressure, cholesterol and blood sugar levels. A 5 % goal is also easier to reach and keep than a large one.
How long will it take to reach my goal weight?
Divide the total you want to lose by your weekly pace. At about 0.5 kg a week, 10 kg takes around 20 weeks on paper, and the pace usually slows as you get closer.
Can teenagers use BMI to set a goal weight?
No. Adult BMI categories apply from age 20; children and teenagers are assessed with age- and sex-specific growth references. Anyone under 18 should talk to a doctor before trying to lose weight.
Sources
This article is general information, not medical advice. If you have a health condition, are pregnant or under 18, talk to a doctor or registered dietitian before changing your diet.