How much weight fluctuation is normal

[FloofyBird]

I weighed myself the other day and was 12 stone 8

a few days later I was 12 stone 1

today, another few days later I'm 12 stone 6

is it normal to gain/lose 5-7lb like this? I assume it's related to water rather than fat but how do I figure out my actual weight and if I'm actually losing fat when it fluctuates to such a high degree?

I find it steady on a flat hard floor like bathroom or kitchen. I only varied this much weighing on a carpet. Also weigh yourself on a morning after using the bathroom without many/any clothes on.
You can also try boots weighing machines for £1 and they also do free health checks for over 40.
Drinking plenty of water will minimise water retention.

I can have a 2kg fluctuation from one day to the next.

Thanks @Histoscientist. I do weigh on a hard floor and drink around 1.5-2l a day.

Do you weigh on a morning? Do you have upto date scales? I mainly go down or maintain a few weeks rarely go up.

To see if I’m losing fat I’ve got scales which measure body composition. No, it’s by no means exact, probably far off. And it can massively vary day to day, too. But, over time, there’s the trend that gives a (for me) good enough indication.

I can vary day to day by about 2kg sometimes more, same scales, with an app, same tile on the bathroom lines up.. I think it’s water.