# Insulin calculations

How do I calculate how much insulin to inject with a BS =216,1:10 carb ratio, 25 correction factor, 1 unit for 40 over 120? I switched back to injections from the pump. Feeling silly but want to be sure I am calculating this right. Thx.

I think there are apps with similar functions available now as well (canâ€™t recommend/vouch for any of them or for the calculator above first-hand since I personally use a pump, but Integrated Diabetes is a very credible source in general).

The general rule for correcting a high blood glucose needs a target number to start. Iâ€™m guessing from what you wrote is that your target is 120 mg/dL.

The first step is to calculate the amount of the correction you need:

216 - 120 = 96

Then use your insulin sensitivity or correction factor (yours is 25) and divide that into the number calculated above:

96/25 = 3.84 units of insulin

If youâ€™re using a syringe and vial, I would round up to 4 units but if you want to add a margin of safety then deliver 3.5 units.

Iâ€™m a little confused about what â€ś1 unit for 40 over 120â€ť means. Perhaps your doctor wants to be more conservative with corrections that are near your 120 goal. If thatâ€™s true then your doctor may want you to take a less aggressive correction, but it does confuse the situation. If you can clarify, I might be able to check your math.

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Thank you, that was very helpful. I will clarify my docâ€™s orders.

Thx all for the help with my questions. I met with my CDE-NP and admitted that I needed help. She apologized for assuming I knew how to calculate doses bc I was on a pump. Prior to the pump-5yrs. ago-I used a SS. Only! She was shocked. Technology has leapt light years in that time. We then agreed, much to my dismay, that I didnâ€™t have the best insulin therapy. Lesson learnedâ€¦ never assume anything.