You are at 84 kg (185 lb), your goal is 78 kg (172 lb), and a holiday or a wedding sits in the calendar. No single weigh-in tells you whether the date fits. Your weekly rate does: how many kilos your trend actually loses per week.
The goal date comes from one division. Divide the distance between your trend weight and your goal by the weekly rate and you get the number of weeks. With 6 kg (13 lb) to go and a rate of 0.4 kg (0.9 lb) per week, that is 15 weeks. Trendcurve does this for you, sets it against the pace you planned, and warns you when that pace is too high. Goal and target rate are free. The forecast with a date is Pro.
How the goal date is calculated
The app takes your trend values from the last 14 days and fits a regression line through them. The slope of that line is your weekly rate. It rests on the trend and not on raw readings, because daily values scatter with water, salt and digestion. Trend weight instead of the daily value explains why.
Trendcurve then extends the line toward your goal. Where it crosses the goal weight, you find the date. Below it, the card shows a range with an earliest and a latest day. The range comes from how much your rate scatters: the noisier your curve, the further apart the two days sit.
The result is a projection, not a promise. When your rate changes, the date moves with it.
The line continues in a straight path. It knows nothing about holidays or diet breaks, and it cannot know that the rate usually falls toward the end, because a lighter body burns less. The last kilos often take longer than the sum says. After a longer break you can restart the trend (Pro), and the app rebuilds the rate from the new values.
Setting up a goal and a target rate
Open the "Goal" tab. There you choose whether you want to lose, gain or maintain weight, and you enter your goal weight. A safeguard blocks goals in the underweight range. Once your trend reaches the goal, the app offers to switch to "Maintain".
You enter the target rate as an amount per week, in kg or lb. While you type, the app converts the value into a percentage of your body weight and tells you whether it falls in a common range. If you leave the field empty, there is no fixed rate and nothing to compare. With a target rate, the forecast card shows two lines, Planned and Actual, and how many days you are ahead of or behind plan. In the forecast chart the target rate appears as a dashed line beside your trend and the projection.
Maintain mode has no goal date. There the corridor around your goal weight counts.
A worked example
Your trend weight is 84 kg and your goal is 78 kg. You enter a target rate of 0.6 kg (1.3 lb) per week. When gaining, the app calculates the same way with the opposite sign.
| Rate per week | Time to 78 kg | |
|---|---|---|
| Planned | 0.6 kg (1.3 lb) | 10 weeks |
| Actual | 0.4 kg (0.9 lb) | 15 weeks |
The plan says 10 weeks and the measurement says 15. The card shows you about 35 days behind plan, and the bar shows how far you have come between start weight and goal. Your target rate equals roughly 0.7 percent of body weight at 84 kg. That sits inside the usual range of 0.5 to 1 percent, which How fast should you lose weight? covers. The measured rate sits just below it. You can plan more movement, trim calories slightly, or set the target rate to 0.4 kg. At 0.4 kg the card reads "Right on plan." and the date lands at about 15 weeks.
A date is only worth reading once the 14-day window is filled. Look at the card after three days and you read a rate from an almost empty window.
When the app shows no date
Trendcurve prefers to show no number over a wrong one. In place of a date, the card names the reason:
- Too few measurements: it needs at least 7 days with a weigh-in in total, 4 of them in the 14-day window or since the last trend restart.
- Measurement too old: your last weigh-in is more than three days back.
- Plateau: the trend moves by less than 0.1 kg per week.
- Wrong direction: the trend is moving away from the goal. A date appears as soon as it turns.
- Too far away: at the current rate it would take more than two years.
For a plateau, the wrong direction and a distant goal, the forecast chart still draws the projection for 60 days so you can see the direction. That produces no goal date.
The warning at one percent per week
If your target rate or your measured rate exceeds 1 percent of body weight per week, Trendcurve warns you. At 84 kg that is 0.84 kg (1.9 lb). When you enter such a rate, the app asks whether you want to adjust it or keep it anyway. The decision stays yours. A rate that high is usually hard to sustain.
The warning also applies to the measured rate. If you lose 1.5 kg (3.3 lb) in the first week of a diet, the card shows the notice even though you set no target rate. Most of that start is water, and the rate usually settles after a week or two. The target rate also sets the target budget in the calorie budget (Pro). With medication, illness or pregnancy, ask a doctor about your pace. Trendcurve is not a medical device.
What is free and what is Pro
| Feature | Free | Pro |
|---|---|---|
| Goal with progress bar | yes | yes |
| Target rate with pace warning | yes | yes |
| Forecast with goal date and range | no | yes |
| Planned versus actual, days ahead or behind | no | yes |
| Forecast chart with projection | no | yes |
Free users see the progress bar and get the pace warning, even when no date appears. The goal date is an estimate based on the last 14 days. Check it once a week, not daily, and when it drifts by more than two weeks, adjust your target rate first and your goal second.