Tatcha cleansing oil

I've only gotten the little sample pump bottle of the oil, and I use about 4 pumps a night (it may dispense less than the full size pump?) and it's lasted me two weeks. Just coming to the end of it now. So even though I don't have a definitive answer to your question, I DO know it lasts longer than I thought it was going to!

There are several variables to consider. I don't know if this will help you or not, but.....

The camellia oil cleanser I use comes in a 200 ml. bottle (6.76 oz.).
Tatcha cameilla oil cleanser is 5.1 oz., which is roughly 150 ml.

I use two pumps of mine, nighttime only, and I'm still on my first bottle, but expect to run out in a few days, which means it's lasted me 3 months. I have no way of knowing if yours and mine pump out equivalent amounts, but on the Tatcha listing, they do recommend that you use two pumps per cleanse. That said, I would guess yours would last somewhere around 2-2.5 months, if you do that. However, other variables would be.... will you be using it morning and night? If so, using one pump each time, it would still last you 2-2.5 mos. If a single pump turns out not to be enough and you have to use more, but are using night and day, then that would reduce how long a bottle by half the time.

I've had mine for a while-three months at least, and it still feels like there's a lot in the bottle. I use more than one pump and massage it into the skin for a long time before I rinse it off-like 10 to 20 minutes. I can really feel it pulling debris out of my pores.