From AussieEnglish.com (but as they say in that link, it would be familiar to Anglophones everywhere)... to nail [it / something] if you nail something or you nail it in a figurative sense it means that you have completed a task successfully, perfectly, impressively , or you’ve gotten something correct, you know, you’ve gotten something right.
Note - using this idiomatic expression (as in I've nailed that tricky job ) doesn't inherently include the sense of ...
and I'm proud of having done so , but in practice that would always be implicit.
ell.stackexchange.com/users/126/FumbleFingers Reinstate Monica
In English we use a French word: voilà!
In context, its meaning is something like "I've done something pretty good, if I don't say so myself!"
or "What I've done is admirable, wouldn't you agree!"
You will actually encounter the word spelled wa-la by speakers who have heard it used but have never read it, or if they have read it, have not recognized it.
ell.stackexchange.com/users/10264/Tᴚoɯɐuo
In British casual usage, to emphasise that the task was not merely completed (as "I've done it" might be taken to mean) but done well in a way satisfying to the speaker, people might say I've aced it
, I've smashed it, and further intensification is possible by preceding the verb with 'totally', 'completely', etc. 8 guaranteed ways to totally smash your ‘to do’ list in 2015
How I Smashed Out My Christmas Shopping In Two Hours Since starting with Sustain, I've totally smashed my goals his sassy kid totally aced his maths test
ell.stackexchange.com/users/46805/Michael Harvey
If I have just completed a twenty-year task, my exclamation would most likely be "Finally!", or perhaps "At last!"
If it's not a long, protracted project then the phrases like "Nailed it!" or even "Yesss" would be appropriate.
On short-term achievements I occasionally say "D*mn, I'm good!"
ell.stackexchange.com/users/75223/Tom Williams
there you go : You're doing that well or correctly; nice job.
Example: There you go!
I knew you'd get the hang of it eventually!
This is the context provided by the OP: Say, I had been building a house for 20 years and finally built it Well,
then in that case, you could say something like this: Finally done!
ell.stackexchange.com/users/6450/Michael Rybkin
With the caveat that it has acquired an ironic connotation , mission accomplished is appropriate for completing a long effort.
ell.stackexchange.com/users/57779/nanoman
(It's) done and dusted .‎‎
adjective, not comparable ‎
(Britain, idiomatic, of a task) Completed thoroughly and satisfactorily.
Wiktionary
ell.stackexchange.com/users/72872/Bence Mélykúti
"I've done it!"
has exactly the meaning you are looking for.
In American English, we don't have much in the way of idioms for this, as the previously answers demonstrate: "nailed it" is Australian
, I gather "done and dusted" is British, and "voila", from the French, is not really conventional English usage for what you have in mind.
When I completed the requirements for my graduate degree, and got the letter saying I had been approved for graduation, I posted to social networking the single word "Approved" and a photo of the letter.
Everyone got it, and the congratulations came pouring in.
There was no idiom that struck me as more appropriate than that.
ell.stackexchange.com/users/5890/Codeswitcher
My Dad would always say "that was a home run" after finishing a big project well or faster than expected.
Obviously, this comes from baseball.
ell.stackexchange.com/users/51492/Stephen S
'Sorted!'
As SE doesn't like pithy answers, I'll share a story of my late friend 'Kip' Carpenter, creator of the 'Catweazle' character and TV series.
He was looking for a wrap-up line for another script.
Eventually someone suggested 'Sorted!'.
And it was.
https://en.wikipedia.org/wiki/Catweazle
ell.stackexchange.com/users/14011/Laurence Payne
You raise your fist to the sky and shout "Excelsior!"
It's an English modification of a Latin word and has been used for more than two centuries.
ell.stackexchange.com/users/68607/user68607
What is an idiom of:   "I have just finished a great job and I'm extremely proud of that"   For example, I had been building a house for 20 years and finally built it (and want everybody to know)  I thought "I've done it!" will do, but Google seems not to confirm that. Is there a simple idiom (just an exclamation)?
Idiom for "I have just finished a great job and I'm proud"
ell.stackexchange.com
<idiom-request>
ell.stackexchange.com/questions/166251
ell.stackexchange.com/users/31934/Serguei
"I've nailed it!", "I've smashed it!", "I've done it!", "Sorted!", "There you go!" or "Mission accomplished!" are all used in this context. I've done it" could have that meaning, but "I've nailed/smashed it" means that you've done exceptionally well, and can be intensified with words like 'totally', 'completely', etc. "Sorted!" has a similar connotation. "There you go" and "Mission accomplished" can be used, but some expressions like this can be used ironically.
I've done it" could have that meaning, but "I've nailed/smashed it" means that you've done exceptionally well, and can be intensified with words like 'totally', 'completely', etc. "Sorted!" has a similar connotation. "There you go" and "Mission accomplished" can be used, but some expressions like this can be used ironically.