Diabetic Carb Counting Per Meal Calculator
Split a daily carbohydrate budget into per-meal and per-snack carb targets, and estimate mealtime insulin from your carb-to-insulin ratio.
How it works
Meal carbs = (daily budget − snacks × snack carbs) ÷ meals · Mealtime insulin = meal carbs ÷ carb-to-insulin ratio
Carb counting matches carbohydrate intake to a daily budget and, for people on rapid-acting insulin, to mealtime doses. After setting aside carbs for snacks, the remainder is divided evenly across main meals, and the carb-to-insulin ratio (grams of carb covered by one unit) estimates the bolus for each meal. These figures are planning aids — your actual insulin doses must come from your care team and be adjusted for blood glucose and correction factors.
Worked example
A 180 g budget with 2 snacks at 15 g each leaves 150 g for meals; over 3 meals that is 50 g each. At a 1:10 carb ratio, a 50 g meal needs about 5 units of rapid-acting insulin before eating.
Frequently asked questions
What is a carb-to-insulin ratio?
It is the number of grams of carbohydrate that one unit of rapid-acting insulin covers. A 1:10 ratio means 1 unit per 10 g of carbs; your ratio is set individually and may differ between meals.
Does this replace my prescribed insulin plan?
No. This is an educational planning tool. Real dosing must follow your healthcare provider’s instructions and also account for current blood glucose, correction doses, activity and illness.
Should carbs be split evenly across meals?
Even splits are a simple starting point that helps keep blood glucose stable, but many people tailor larger or smaller carb amounts to specific meals. Adjust with your care team based on your glucose patterns.
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Educational planning tool only — not medical advice. Insulin dosing and carb targets for diabetes must be set and adjusted by your healthcare provider.