Insulin Calculator

TeraFlop

About this app

Insulin Calculator helps people with diabetes quickly calculate insulin doses based on carbohydrate intake and blood glucose readings.

Built by a parent of a child with Type 1 diabetes, this app was designed to be fast, accurate, and easy to use — especially during the busy moments when you need it most.

★ KEY FEATURES

▸ Carb Dose Calculation
Enter the carbs you plan to eat and your insulin-to-carb ratio. The app instantly calculates how many units of insulin you need.

▸ Correction Dose Calculation
Enter your current glucose reading, correction factor, and target. The app calculates the correction dose needed to bring your glucose back to target.

▸ Transparent Math
Every calculation shows the full formula and breakdown so you can see exactly how your dose was calculated. No black boxes — just clear, verifiable math.

▸ Dexcom CGM Trend Support
Select your current CGM trend arrow (from ↑↑ rapidly rising to ↓↓ rapidly falling) to factor glucose trends into your dose calculation. Supports both mg/dL and mmol/L adjustments.

▸ Multiple Profiles
Create profiles for different times of day — breakfast, lunch, dinner, or anything else. Set carb ratio, correction factor, and target for each profile. Profiles can switch automatically on a 24-hour schedule or be selected manually.

▸ 24-Hour Schedule
Assign profiles to time ranges so the correct ratios are loaded automatically throughout the day.

▸ Configurable Dose Rounding
Round doses to 1 unit, 0.5 unit, 0.1 unit, or 0.05 unit increments to match your insulin pen or pump precision.

▸ mg/dL and mmol/L Support
Switch between glucose units at any time. All values and trend adjustments update automatically.

▸ Dark & Light Themes
Choose between dark mode, light mode, or auto (follows your system setting).

▸ Privacy First
No accounts. No data collection. No internet required. All your data stays on your device.

★ IMPORTANT NOTICE

This app helps you make insulin dosing calculations. You are strongly encouraged to confirm any information with your professional healthcare provider and to review all information regarding any medical treatment. This app is not associated with Dexcom or any other medical provider. For medical emergencies call 911 immediately.

This app is NOT a medical device and is NOT intended to replace professional medical advice, diagnosis, or treatment. Always consult your physician or qualified health provider with questions about a medical condition.

Ratings and reviews

I made a spreadsheet to calculate dosage using instructions from my Dr. Then I found this app. It was a bit confusing at first because the output didn't match. I searched medical sites and found the default definition of the diabetic correction factor. Bang! Numbers are right on for me. Everyone is different so the correction entry should be set to your correct value. Add information button for the fields and you get 5 stars.

The rounding factor is on point. I suggest you double check the math often to make sure it is making the right suggestion.

Simple, easy to use, and free. What more do you need from a bolus calculator? I'm just happy not to have to do mental math or find a scrap of paper to figure out my insulin dose.