てよかった details

write + (and…) + I'm glad I did

kaite yokatta

I'm glad I did; it turned out well that…

この店みせを選えらんでよかった。

kono mise o erande yokatta.

I'm glad we chose this place. casual

傘かさ、持もってきてよかった。急きゅうに降ふってきたね。

kasa, motte kite yokatta. kyuu ni futte kita ne.

Glad I brought an umbrella — it just started pouring. casual

Examples

I'm glad I did — relief that something took place and turned out well

この店みせを選えらんでよかった。

kono mise o erande yokatta.

I'm glad we chose this place. casual

傘かさ、持もってきてよかった。急きゅうに降ふってきたね。

kasa, motte kite yokatta. kyuu ni futte kita ne.

Glad I brought an umbrella — it just started pouring. casual

早はやめにご相談そうだんくださって、本当ほんとうによかったです。

hayame ni go soudan kudasatte, hontou ni yokatta desu.

I'm very glad you came to us about it early. formal

I'm glad I didn't — relief that something was avoided

あの日ひ、無理むりして出でかけなくてよかった。

ano hi, muri shite dekakenakute yokatta.

I'm glad I didn't force myself to go out that day. casual

何なにも言いわなくてよかったと、今いまでも思おもいます。

nani mo iwanakute yokatta to, ima demo omoimasu.

Even now I think it was good that I said nothing. neutral

I'm glad it was — relief about how something turned out, with an adjective or a noun

思おもったより安やすくてよかった。

omotta yori yasukute yokatta.

I'm glad it was cheaper than I expected. casual

ご家族かぞくの皆みなさんがご無事ぶじでよかったです。

go kazoku no minasan ga go buji de yokatta desu.

I'm glad everyone in your family is safe. formal

会場かいじょうが駅えきの近ちかくでよかったですね。

kaijou ga eki no chikaku de yokatta desu ne.

It's lucky the venue is near the station, isn't it. neutral

The fact has to be settled, not past — 明日あしたが休やすみでよかった is fine,
×明日あした晴はれてよかった is not. For something still undecided the frames
are 〜といい and 〜ますように.

ばよかった
The same よかった on opposite sides of what happened — 相談そうだんしてよかった says the act took place and was right, 相談そうだんすればよかった says it never took place and should have.

てもいい
One も apart in the past — 行いってよかった states you went and are glad of it, while 行いってもよかった grants that going would have been permitted and leaves whether you went open, so out of the blue it is heard as a missed option.