Get an oral syringe. Or a calibrated glass dropper from Amazon for $4.44 with Prime.

There's no way we can reliably estimate the volume of a drop from a pipette. It depends on the force with which it is squeezed, substance viscosity to some degree, the diameter of the opening at the bottom of the pipette...

I've measured the volume of drops from several droppers and pipettes and the volume varies pretty wildly. Even drop to drop.

Take the guesswork out of it and just get the dropper. Measuring is the key to moderation. :)