How many Lantus SoloStar pens 100 Units/mL at 70 units a day be needed for a 90 supply?

I take the exact same dosage! I'm not sure if you split between morning and night doses or the entire 70 units at once, but I take 35 in the morning and 35 at night. SoloStar pens come with 3 mL of insulin, so there are 300 units in a given pen. 70 units/day times 90 days equals 6300 units, which comes out to 21 pens with no remainder. However, you have to calculate extra units for "queueing up" each pen needle you use (getting the insulin actually flowing through), and I usually budget about 2 "queueing" units per shot, which comes out to 4 units a day for me. that adds another 360 units, which is another two pens, bringing the total number of pens needed to 23.

I'm pretty sure that works out to 63 with nothing left over.