The adverbs continually and continuously are pretty similar. But they have slightly different meanings.
In many situations, you could probably use either one. It would make very little difference for your readers.
It’s not a classic grammar mistake. However, if you want to make sure you are using the correct word, it helps to know the respective meanings.
In essence, it’s about actions that either never stop or actions that stop and start.
The difference between continually and continuously
When we say that something happens continually, it means repeatedly, over and over again, or frequently.
Continuously, on the other hand, refers to an action that is ongoing, unbroken, or non-stop.
It might not seem like a lot of difference. But in some contexts, you might want to think about which one to use.
Let’s look at a couple of quick examples.
Even when he’s on holiday, Michael continuously checks his work emails. Wrong
In this sense, it would mean that Michael does nothing else except check his emails.
Even when he’s on holiday, Michael continually checks his work emails. Correct
Now it’s correct because it says that Michael regularly checks his emails.
It doesn’t say how often, but it could mean once, twice, or a few times a day.
The easy way to make the right choice is to decide if the action is always or frequent.
More examples of the difference between continually and continuously
You only need to get into the habit of differentiating between recurring events and ongoing actions. Then it’s very easy to get this grammar point right.
My website is continuously updated to the latest software version. Wrong
My website is continually updated to the latest software version. Correct
These updates occur regularly. They could be weekly, monthly, or from time to time.
A web application firewall continually scans my site for suspicious traffic. Wrong
A web application firewall continuously scans my site for suspicious traffic. Correct
In this example, the firewall scanner is working 24/7 to protect my site. It never stops working, even for a second.
I continuously delete spam comments on my blog. Wrong
I continually delete spam comments on my blog. Correct
No, I don’t delete every single one as it arrives. I usually delete spam comments once a day or so.
Choosing between continual and continuous
Continual and continuous are the adjective forms of continually and continuously.
They share the same meaning, but they describe nouns instead of defining an action.
Our holiday was ruined by continuous rain.
In this use, it says that it rained all the time and it never stopped for a moment while they were on holiday.
The continual messages and emails meant Michael couldn’t switch off and enjoy our break.
We don’t know how frequent, but it says that the messages and emails arrived at regular intervals.
Can you grade continual and continuous?
You would rarely need to, but it is possible.
You can modify the two words in a similar way that you would grade a word such as always with nearly or almost.
The doctor is almost/nearly always late for his appointments.
Almost/nearly continuous rain ruined our holiday.
The almost/nearly continual messages were a distraction we could have done without.
Are constant and constantly the same?
They are similar but not quite the same.
When we use these two words, they say that it is a repeated action like continually.
But the difference in meaning is that the result of the action is always the same.
Sometimes it is about negative results.
I’m constantly complaining about the heating in the office, but it never gets fixed.
The frost on the windows is a constant reminder of how cold it is in our building.
But it can also have positive uses.
I’m constantly amazed by how fast my little boy learns new words.
It’s hard work, but I know I’m making constant improvements to my writing.
Constant can also be a noun as in this well-known quote.
The only constant in life is change. – Heraclitus
Quick reference summary
Here’s a brief recap of these three very similar word forms.
Continuously and continuous: You use these when you are referring to a continuing action with no interruption.
Continually and continual: Use these with an action that repeats regularly and often.
Constantly and constant: This is the correct choice when a repeated action always results in the same outcome.
Now you will have no problem at all choosing the right word.
Related reading: What’s The Difference Between Obliged And Obligated?