Hi felinefanatic. I have 4 cats that are all over 9lbs and I also buy the large dog advantage for them and then measure it out. Please be sure to put some masking tape on the syringe though because the numbers will wear off over time.

For cats over 9lbs- use .8ml; this is the amount that comes in each tube if you buy the advantage for cats and kittens 8 weeks and older and over 9lbs. If you have any questions you should call your vet or go to your vets and they can mark the syringe for you. You can also use a little less too.

I don't know the amount to use for cats under 9lbs. Another thing that I've learned is to not squirt all of the advantage out in the same spot on your cat. My cats Storm and Sunny are very sensitive and have had hot spots from the advantage.

Now I squirt a little bit out in about 3-4 areas on them. I start at the neck and go to the upper back. Good luck and like I said if you need any further information, please ask your vet. I'd hate to give you any misinformation.