Weekly average weight calculator
Paste your weigh-ins or load an export. The calculator groups every calendar week from Monday to Sunday and shows the average, the change vs last week in weight and as a percentage of body weight, and your trend weight next to it. For losing, maintaining, bulking and cutting.
Your data never leaves your browser
The calculation runs entirely on your device. No upload, no account and nothing stored on our server.
Order and separators don't matter, comma or dot as decimal mark. Several weigh-ins on the same day are averaged.
Drop a file here or
Apple Health (export.zip or export.xml), Withings (weight.csv or ZIP), Google Fit (Takeout CSV), Happy Scale, Libra, openScale, Trendcurve and any CSV with a date and a weight column.
Your weeks Example data
This is made-up example data covering twelve weeks, so you can see what a result looks like. Paste your own weigh-ins above.
Change per week
Weekly table
| Week | Days weighed | Average | Change | in % | Trend at week end |
|---|
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Every day, automatically: Trendcurve for iPhone and Android
The app reads your weight from Apple Health or Health Connect and shows your trend and 7-day change, no copying and pasting. Free, no account, your weigh-ins stay on your device.
Your trend after every weigh-in, not just on Sunday
Trendcurve recalculates your trend weight after every weigh-in and shows the 7-day change. You choose the method: a moving average over 7 or 14 days or exponential smoothing, all free. The app can read your weight from Apple Health. With Pro you see your weekday pattern: how far each weekday sits above or below your trend on average.
Why a weekly average tells you more than a single weigh-in
Your weight moves from day to day, often by 1 to 2 kg (2 to 4 lb), because of water, salt, carbs and digestion. A single reading therefore says little about whether you lost or gained fat this week.
The weekly average combines every day you weighed in during a calendar week. With seven days, an outlier moves it by only a seventh of its size: a reading 1.4 kg above your usual level lifts the average by 0.2 kg. And because each weekday is in it exactly once, a heavier day after the weekend and a lighter midweek day cancel out.
During a cut or bulk you can check your pace this way: if this week's average is 0.3 kg below last week's, that is more reliable than comparing two single Mondays.
Where the weekly average is weaker than a moving trend
- It moves in steps. Within a week you get no new value, only with the next complete week. A moving trend updates after every weigh-in.
- It describes the middle of the week on average. By Sunday the average is already a few days old.
- Missing days distort it. If you only weigh in on Monday and Tuesday, the average consists only of the days after the weekend, which are higher for many people. A trend also uses the weeks before and copes better with gaps.
- The calendar boundary is arbitrary. A weekend of salty food lands in one particular week and can exaggerate the change vs last week there, then soften it the week after.
- The change between two weeks rests on at most seven values on each side. Over several weeks it becomes steadier, which is why the calculator also shows the average change per week.
How the calculator works
- Several weigh-ins on the same day are first averaged into one daily value, just like in the Trendcurve app. A day with three weigh-ins does not count three times.
- Each calendar week runs from Monday to Sunday in your local time, and the week number follows ISO 8601.
- The weekly average is the mean of that week's daily values. The change refers to the previous week with weigh-ins. If a week is missing in between, the table shows which week the change refers to.
- The change in percent is the change divided by the previous week's average.
- Next to it you see the trend weight on the Sunday of the week, or on the last day weighed in the current week. It comes from exponential smoothing, the app's default method.
How to use the table
- Compare mainly weeks with at least four days weighed, and weigh yourself under conditions that are as similar as possible, for example in the morning before breakfast.
- The percent column shows your pace relative to your weight. The Trendcurve app warns when a target pace is more than one percent of body weight per week.
- In a bulk the changes are small and often switch sign. Look at the average change over several weeks rather than at a single week.
- If a week is out of line (holidays, travel, illness, cycle), wait for the following week before you change calories or training.
- With the CSV export you can continue the table in Excel, Numbers or Google Sheets or hand it to your coach.