Guide · Calculator
How to calculate your weekly weight average
To calculate a weekly weight average, add the weights you recorded that week and divide by the number of days with a reading. Use the same unit throughout. Leave missing days out of both the total and the count.
Subjective Health is a product of Centurion Movement, LLC.
Link to this guide: https://subjective.health/resources/weekly-weight-average
Average your week’s readings
Enter one weight for each day you recorded it, all from the same Sunday–Saturday week. Leave other days blank.
Add a reading to see your average. No readings means no average yet.
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This is an average of the readings you enter, not a week-to-week comparison or a medical interpretation.
Prefer paper? Download a blank weekly weight log, then bring your recorded readings back to this calculator.
The formula, in three steps
- Choose one week and collect one recorded weight per day. Here, a week runs Sunday to Saturday.
- Add those readings together, using either pounds (lb) or kilograms (kg).
- Divide the total by the number of recorded days. Keep the unit beside your answer.
Average weight = total of recorded weights ÷ number of recorded days
This is the arithmetic mean. NIST’s definition of the mean uses the same sum-and-count rule. You divide by seven only when all seven days have a reading.
A worked example: five recorded days
These are made-up readings in pounds, not a target or a real person’s record. There is no reading for Tuesday or Thursday.
| Day | Recorded weight |
|---|---|
| Sunday | 180.4 lb |
| Monday | 179.8 lb |
| Tuesday | Not recorded |
| Wednesday | 180.2 lb |
| Thursday | Not recorded |
| Friday | 180.0 lb |
| Saturday | 179.6 lb |
180.4 + 179.8 + 180.2 + 180.0 + 179.6 = 900.0 lb
900.0 ÷ 5 = 180.0 lb
Average of five recorded days. Two days remain unknown.
Keep the precision of your readings while adding and dividing. Round the final answer to one decimal place if you want a short label. For example, “180.0 lb, from five recorded days” says more than “180.0” alone.
Missing days stay missing
A blank day is not a zero-weight day. In the example, dividing 900.0 by seven would treat two unknown readings as zero. Divide by five because five days were recorded.
With no readings, there is no average to calculate. With one reading, the average equals that reading; it still represents only one day. You do not need to invent readings to finish the week.
Keep the units clear
Pounds and kilograms cannot be added as though they were the same unit. Convert any mixed readings to a single unit before calculating. If a reading has no known unit, check the original record instead of guessing.
Keep the meaning modest
An average summarizes the readings included in it. It does not fill gaps, establish a trend on its own, or explain why a number changed. A week with two readings and a week with seven have different coverage; keep that count visible when you look back.
How Subjective uses your readings
Subjective keeps one recorded weight per day and uses a Sunday–Saturday week in your account’s timezone. Its weekly average uses the available readings. A reading with an unknown unit stays unavailable for the calculation.
The app’s comparison has an extra rule. For a week still in progress, it compares the same elapsed part of the prior week. On Wednesday, for example, it uses Sunday through Wednesday in each week. Each window averages its own available readings; the recorded weekdays do not have to match.
A displayed change needs readings on at least two days in each window. If there is not enough information, the comparison stays unavailable. A dash means unavailable, not zero.
That comparison is separate from the single-week arithmetic above. Neither number proves a change in body fat. The program’s weekly review leaves room to look at coverage and your own notes before choosing what to do next.
Sources and scope
- NIST: Measures of Location
The definition of the arithmetic mean: the total of the observations divided by their count.
- How the Subjective weekly review works
The product’s Sunday–Saturday week, optional review and handling of available records.
Examples are illustrative. This guide explains recordkeeping and the product; it is not medical advice or a treatment plan.