Tallyband

Export Fitbit weight data, and the pounds or kilograms trap

Weigh-ins from an Aria scale, or typed into the app, are in your Google Takeout archive with BMI and body fat. The catch: the weight is written without a unit. Here is where to find them and how to tell pounds from kilograms in seconds.

Open your Takeout archive

Where the weigh-ins are

In a Takeout archive, open Takeout/Fitbit/Global Export Data/ and look for files named weight-2026-03-01.json, one per month. In archives from the older fitbit.com export they sit in Personal & Account. Each weigh-in looks like this:

{
  "logId" : 1740000000000,
  "weight" : 172.4,
  "bmi" : 24.68,
  "fat" : 21.5,
  "date" : "03/01/26",
  "time" : "07:12:30",
  "source" : "Aria"
}

The date is month, day, two-digit year. fat is the body fat percentage and is missing when the scale did not measure it. source says where the number came from: a scale, the app, or another service. Newer archives may also have weight.csv in a _GoogleData folder, where the column name gives the unit (grams).

Pounds or kilograms?

The JSON files give no unit. One open-source converter reads them as pounds; another assumes kilograms. You can settle it for your own file with the BMI saved next to each weight:

Weight divided by BMI
Weight ÷ BMIUnitWhy
about 2.1 to 4.4kilogramsBMI is kilograms divided by height in metres squared, so weight ÷ BMI is your height squared: 1.45 m to 2.10 m gives 2.1 to 4.4.
about 4.6 to 9.7poundsThe same number times 2.2046.

The example above: 172.4 ÷ 24.68 = 6.99, so it is pounds (78.2 kg). The two ranges never overlap for an adult. Tallyband does this check on all your weigh-ins, says which unit it found, and writes both kilograms and pounds. If your archive has no BMI (no height in your profile), compare one weigh-in with the app and set the unit yourself.

Get them as a CSV for a date range

  1. Request your archive in Google Takeout with Google Health ticked. If it seems stuck, it is probably still being built.
  2. Open the ZIP in Tallyband and set the dates.
  3. Download the Weight CSV: date, time, kg, lb, BMI, body fat and source for every weigh-in. The daily summary also has the day's last weigh-in.

Download every weigh-in with BMI and body fat, in kilograms and pounds. Nothing is uploaded.

Open your Takeout archive

Tallyband Pro, $8 paid once: everything for your dates in one Excel file or one ZIP of CSV files, plus every heart-rate reading and steps minute by minute. Get Pro on Gumroad or see what is free.

Questions

Can I export only my Fitbit weight data?

Google Takeout exports the whole Google Health archive at once. Open it in Tallyband and download only the Weight CSV, for the dates you choose.

Why is my Fitbit weight export in pounds when I use kilograms?

The archive writes weight without a unit, and the number is not always in the unit the app shows. Divide one weight by its BMI: a result above 4.5 means pounds, below 4.4 kilograms.

Does the export include body fat?

Yes, when it was measured: the fat field holds the percentage. A weigh-in without a body fat reading has no fat field.

Sources

Last checked: October 29, 2026.

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