Finally, at last, lastly and in the end all these adverbs denote ‘after a period of time’. However, we use them in different ways. There can be subtle differences, in certain contexts where one sounds better than another. A lot depends on the context.
Finally = we use finally to refer to something that happened after a long time or after considerable delay and usually after some difficulties. In this context, finally normally appears in the mid position for adverbs, between the subject and the main verb, after the modal verb or the first auxiliary verb, or after be as the main verb:
She got caught in the rain and finally got home at midnight.
We finally found a decent playschool nearby for Emma.
After three unsuccessful attempts, she finally passed her learner’s test.
After the usual hiccups that come with any business, the new project finally took off.
So Sarah and Frank finally got married, did they?
The project has finally been approved by the president.
He finally apologized, but didn’t seem to be very graceful about it.
After months of working, the overbridge has finally been built.
And finally, I’d like to thank you all for your support and cooperation.
We also use finally when we talk about the last in a series of actions:
He zigzagged along the road, had a brush with a couple of cars and finally bumped into a lorry.
After a lot of interrogation, Freddie gave in to the pressure and finally admitted he had stolen the car.
At last = we use at last when something good happens after we have waited for it for a long time:
Sharon has finished her thesis at last!
Jane has at last come round to the idea of going by train.
They have at last sanctioned the leave for the number of days I applied for.
I’m really happy that Kim has made it to the ‘The X Factor’ at last.
At long last the headmaster is starting to listen to students’ problems.
At last I’ve discovered how to connect my cellphone to television!
They have won the match at last! There were so many refereeing mistakes.
At last the operator connected me to the power company who had put me on hold for 15 minutes.
The authorities have at last given him permission to see his son only once but not allowed to talk to him.
Lastly = we use lastly to refer to an event that is the final one in a series. We also use lastly when the events are not similar that we are talking about:
We need soaps, towels, toothbrushes, talcum powder and, lastly, we mustn’t forget pain relievers for grandma.
We also put lastly at the beginning of a clause:
Lastly, I would like to thank all of you for the interest that you have shown in this endeavour.
Lastly, Mr. President, I would like to ask you about your future plans on immigration.
Lastly, could I ask you all to keep away from strangers in this village.
Now lastly, before you go to appear for the final test, I want to mention some tips for sure success.
Lastly, the course helps students think logically.
Firstly it’s too fragile, secondly it’s rather overpriced, and lastly we don’t have a place to put it.
The difference between last and lastly is – for example, if we say ‘Emma gave the apple candy to Liam last’, we usually mean that Emma had given apple candy to several kids and that Liam was the last to get it. If we say ‘Lastly Emma gave the apple candy to Liam’, we mean that Emma had done several things and that the last thing she did was to give apple candy to Liam.
In the end = eventually; ultimately; we use in the end to refer to a conclusion after a long process, after a lot of changes or after a lot of discussions:
Sarah did the cleaning, then cooking, and in the end the washing-up and laundry.
And then, in the end, after weeks of deliberations they proposed a variety of other immigration security measures.
In the end, we decided that the best thing to do was to take an alternative flight with another airline to Edinburgh.
In this typical love story, everything will turn out well in the end.
The Wilsons were planning to go to Austria, but in the end they decided to go to Birmingham.
But in the end, this turned out to be a tragedy with the protagonist ending up in jail.
She broke up with him and the stress of life as a single mother in the end pushed her to the brink of a nervous breakdown.