Videos
Just want to expand my vocabularies on something like this, which I found fascinating these days. Valuable which means something precious or of a certain value that's worth to pay or get, sounds as positive as Invaluable which means something so precious that you can't put a price tag on it. They usually have opposite meaning, like Possible vs Impossible, Understood vs Misunderstood, Beatable vs Unbeatable. I wonder if there are other similar examples.
note: put (?) after "negative" because I'm not sure if they call "In-" or "Im-" a negative prefix in English.
Technically, invaluable works like priceless. They mean that something is of a value which cannot be expressed in numbers. For example great memories, happiness, health, or whatever else you prefer. They are invaluable, because they cannot be sold or bought. They have no price.
On the other hand, valuable means something is of a high value, which can be expressed in numbers. Like a golden ring. It's valuable, because it costs $1000.
Valuable, in American English, is nearly synonymous with invaluable, and is generally used to mean something like useful.
In COCA, valuable appears much more than invaluable, and it is more common in academic writing (where it might be expected as a formal-sounding synonym for good, important, worthwhile, things we need), whereas it is less common in speech. (The speech examples in COCA are from news broadcasters so they may not fully represent unscripted speech.)
From most to least frequent use of valuable, here are some examples of how it's used. In academic writing, it almost exclusively has the more figurative meaning of important; in other places, it sometimes refers to the high monetary value of real goods.
[Acad] modern collections management systems will provide easy access to valuable additional data [Acad] foreign-born faculty members make valuable contributions to the research mission
[Mag] There's a vast supply of valuable metal in Alaska
[Mag] such genetic information will provide valuable insights into issues
[News] thieves who steal copper, brass, bronze and other valuable industrial metals
[News] If you are judging who is the most valuable player then I think Wondo has a great shot
[Fic] A valuable piece of pink jade of that size and perfection
[Fic] from a merchant who was buying a small but valuable patch of groznium-rich soil
[Spok] we're running short of a lot of valuable resources, and we don't have that much zinc
[Spok] There's some really valuable tips there, so I would encourage people to take a look
Invaluable, in COCA, occurs less than valuable, but follows the same pattern of being used more in academic writing, then magazines, news, fiction and finally least in speech. However, I could not find any instances where it clearly refers to real monetary value. Even when a reference to money is made, the meaning is more like very important, so that people say coupon books and funds are invaluable. For example:
[Acad] Finally, the authors acknowledge the invaluable contributions to the project
[Mag] ferns are invaluable for a reliable, low-maintenance understory
[News] These funds were invaluable in giving cash-strapped farmers a chance to remain
[Fic] the gray kitty is Pewter, Market's invaluable assistant, though she's often over here
[Spok] His leadership has also been invaluable in helping our country
Valuable - of a particular (high) value.
Invaluable - of a value that is impossible to estimate.
Which one to use in any particular situation is really up to you. Both are acceptable forms, as far as expressing gratitude goes.
You can say either valuable help or invaluable help.
Valuable means very important or useful, and invaluable means extremely important or useful (too important or useful to be estimated).
Both the words are adjectives; invaluable is stronger than valuable.