Insulin to carbohydrate ratios

Your insulin to carbohydrate ratio (ICR) is a way of working out your mealtime insulin dose more accurately to match the carbohydrates in your food better and to stop your blood glucose level from going too high or low.

An ICR will tell you how much carbohydrate (CHO) will be covered by 1 unit of insulin. For example, an ICR of 1:10 means that 1 unit of insulin is needed for every 10g of carbohydrate eaten.

Because people have different sensitivities to insulin, insulin to carbohydrate ratios can vary between different people and may also be different for different mealtimes.

Your ratio can be increased or decreased to work out what the best ratio is for you.

Mealtime insulin dose calculation

Have a look at the following example of a mealtime insulin calculation for an 80g CHO meal in a person with an ICR of 1:10:

When you are doing some of the calculations, sometimes you will need to round the figure up or down. Most of the time, deciding if the figure should be rounded up or down will be relatively straight forward.

Generally if something is below 0.5 then round down. If it’s above 0.5 then round up. So if you calculate the total carbohydrate as 16.6g, then you would round that up to 17g.