mySugr logoClose side menu
Country selection
Country selection inactive
  • Selected Global


  • Selected Germany


  • Selected America - USA

    America - USA

Language selection
Language selection inactive
  • Selected English


Products and Services

mySugr Bolus Calculator – get help with your insulin dose (currently available in EU)

3/1/2016 by Scott Johnson

mySugr Bolus Calculator – get help with your insulin dose (currently available in EU)

It's time for lunch. Your blood sugar is 165 mg/dl (9.2 mmol/L). You have a big slice of pizza, a bag of chips, and a cold Diet Coke waiting for you. How much insulin do you take?

I can think of a few ways this goes:

  • There’s not much to think about. You always eat the same thing and always take the same amount of insulin. You define the phrase “creature of habit.”
  • You hate thinking about all of this stuff, so you just guess.
  • You love doing a bunch of math before every meal, so calculating your insulin dose is fun and easy.

I can relate to the first two. There’s a lot of value in routine, and I’ve also done my share of guesstimating. That last one? Enjoying all of the diabetes math? I’m sorry. That’s just weird. (I’m teasing. Kind of…) But there’s another option, and it makes thinking about your insulin doses easier and more precise. I’m talking about a bolus calculator.

If you wear an insulin pump, you’re probably already using one (they’re often built-in). You’re welcome to stay and read, but there’s not much new information for you here. However, if you’re using injections (syringes or pens), like most people with diabetes, then stick around. This article should be helpful.

An insulin pen, meter, strips, keyboard, and a bowl of cereal with fruit

So you don’t have (or want) an insulin pump, but I bet you have a smartphone. What does that mean? It means that you should meet mySugr’s Bolus Calculator. It’s a module integrated into the mySugr app that helps with your insulin doses (note: mySugr Bolus Calculator is currently approved for use in Europe).

What the heck is a “bolus,” you ask? Great question. A bolus, in our case, is a single dose of insulin given all at once. In other words, it’s your mealtime shot or a shot to fix a high blood sugar. mySugr’s Bolus Calculator examines all of the messy numbers involved and then recommends a precise dose of insulin.

At mealtime, it’s super easy. Measure your blood sugar, tell mySugr’s Bolus Calculator about your carbs, and we’ll do the rest. We’ll even keep track of your active insulin (also called insulin on board). All you have to do is dial up the dose and take it.

Never heard of active insulin? It’s a concept that helps reduce hypos caused by stacking insulin. We’ll explain it in more detail below.

Getting started

Before using the bolus calculator for the first time, you’ll need to enter some details about how your diabetes works. Once you enter all of these settings, you won’t need to mess with them again unless something changes. There are also a bunch of terms and phrases that might be new to you, but don’t worry; we’ll explain everything.

Bolus Calculator Therapy Settings


mySugr’s Bolus Calculator only works with rapid-acting bolus insulins. You’ll find the list of compatible insulins here and should select the type you’re using.

Active Insulin Duration

Here’s where we talk about active insulin (also known as insulin on board, or bolus on board). When you take a dose of insulin, it stays in your system for a while. The timing is different for each of us, but in general, it starts working in a little bit (about 30-45 minutes), peaks after a longer bit (around 90 minutes), and hangs around in your body (continuing to lower your blood sugar) for hours.

If you take another dose of insulin before your last dose has finished working, you’re supposed to do some math to figure out how much of that old insulin is left (and still lowering your blood sugar). Sounds complicated, right? It totally is. But it’s also totally important.

If you don’t, you could be stacking your insulin, or taking more than you need. And what happens when you take more insulin than you need? That’s right. Low blood sugars.

You can see why it makes sense to know how long insulin works in your body. We call this Active Insulin Duration. If you don’t know what to enter here, you’ll want to check with your doctor. You can also figure it out for yourself, though, with a little time and patience.

The next time you need to fix a mildly high blood sugar, track how long your correction shot (or bolus) continues to lower your blood sugar. Start checking your blood sugar every 30-minutes after the first couple of hours, and once you stabilize, you’ll have your active insulin duration.

It’s important to be sure there’s no old insulin around from a previous shot (or bolus) to mess with your experiment, and it also makes sense to repeat this exercise a few times to make sure you’re getting an accurate read on the situation. And for safety’s sake, check your results with your doctor.


Do you want to dose your insulin in tenths (0.1), half (0.5), or full (1) units? Let us know here, and we’ll make sure your dose recommendations come out like that. It may seem like a silly question to ask, but if you use a syringe with markings for whole units, it might be frustrating to get tenth-of-a-unit suggestions.

Carbs to Insulin Ratio

Maybe you think about your insulin and meals in a much bigger way. Like, “that’s a four unit sandwich,” or, “I’d need at least ten units for that meal,” for example. But we need to do the work from the opposite direction to uncover a piece of the equation.

If you’re counting carbs by grams, we need to know how much work a single unit of insulin can do. In other words, how many carbs can you eat for one unit of insulin? If you’re counting carbs by exchanges, we’ll ask how many units of insulin you take for one exchange.

For example, if you count 15 grams of carbs as one exchange (configured in settings), and would also take one unit for that, then your carb to insulin ratio is 1. If you don’t know your carbs to insulin ratio(s), start by talking with your doctor.

He or she can help find a good place to start, and you can do some testing to fine-tune the setting. You might have different ratios at different times of the day, which you can set here as needed.

Insulin Correction Factor

This setting also talks about how much work a single unit of insulin can do, but here we’re looking at lowering blood sugar rather than covering food. We’re asking how much does 1 unit of insulin lower your blood glucose?

Again, you might have different factors at different times of the day, which you can set here as needed. As with the other settings, if you’re unsure about this talk with your doctor. He or she can help find a good place to start, and you can do some testing to fine-tune things.

In fact, it’s easy to test your correction factor while testing your active insulin duration, as described above. With that, you’d track how many BG points a unit of insulin drops you (Insulin Correction Factor), as well as how long it takes for that unit to stop working in your body (Active Insulin Duration).

And, as described before, it’s smart to repeat this experiment a few times to get an accurate read on the situation, again, being sure there’s no old insulin around to interfere with the experiments. And again, for safety’s sake, check your results with your doctor.

mySugr Settings Screen with the Bolus Calculator Button

Accessing Bolus Calculator Settings

You can find and adjust any of these settings through the side menu. Use the “Profile & Settings” menu item, then the “Settings” tab and you’ll see the “Bolus Calculator Settings” button.

Using the Bolus Calculator

Once your settings have been saved, using the bolus calculator is very straightforward. Enter your blood sugar, and/or carbs, then press the calculate button.

Active insulin is really important, so you may be asked to confirm that you haven’t forgotten to log any recent shots (if you’ve logged them, the bolus calculator will automatically include any active insulin in the calculation). Here’s an example of that confirmation message:

An example of mySugrs Bolus Calculator Active Insulin Confirmation screen

The 4:00 figure in the confirmation example above is based on the Active Insulin Duration setting. If your Active Insulin Duration setting is something different, you’ll see that instead. Here’s how the two buttons work:

  • Cancel – if you suddenly remember a recent shot you forgot to log, that’s no problem. Cancel here and add a new entry for it. In the new entry screen, tap the “Time” field to adjust the timestamp back to when you took that shot (this is the same technique you’d use to do any back entries), enter the appropriate details and save it. Now that you’ve told mySugr about that insulin, you can start your current bolus calculation again (by creating another, current, new entry) and whatever portion of that shot is left (based on your Active Insulin Duration setting) will be included in the calculation.
  • Continue – this confirms you don’t have any active insulin on board, and you can continue with the bolus calculation.

To continue, tap the bolus calculator button again to accept the suggested insulin dose. You’ll see the units automatically move to the appropriate insulin fields and you can fill in any additional details. Save the entry with the green check (upper right corner) or the save button (bottom of the screen).

We’ll record everything and start tracking your active insulin for future bolus calculations. There you have it. A precise, personalized insulin dose calculated just for you.

Paper is for origami

Why isn’t mySugr’s Bolus Calculator available in my country?

mySugr’s Bolus Calculator module is a risk class IIb medical device. That’s higher up the regulatory ladder than our currently approved products and requires additional review by each country’s authorities before we can release it. We currently have approval for use in Europe, and our regulatory team is working to make it available in more countries.

Wrapping up

I hope you’ve gotten a glimpse of easier insulin dosing, and you can see that figuring out how much insulin to take doesn’t have to be such a pain. mySugr can help you do it precisely, safely, and without a lot of work. I know we covered a lot of information today, and that some of it may be new to you. With that in mind, don’t hold back with your questions.

Please, by all means, let me know if I can clarify something or help you better understand anything we’ve talked about today. That’s what I’m here for.

And finally, what else can we build to make your day with diabetes easier? Where else do you find yourself rubbing up against diabetes in all the wrong ways?

Let me know in the comments.

Thanks, Scott

Paper is for origami

Scott Johnson

Almost famous for his addiction to Diet Coke, Scott has lived well with diabetes for almost forty years and is currently the Patient Success Manager, USA for mySugr. He's an active pioneer in the diabetes social media space and along with his work at mySugr, he manages his award-winning blog, when time allows.

Sign up to our newsletter and learn with mySugr.