With all the amazing culture and architecture and poetry it seems like most ancient romans and greeks could read is this true ?
It's an extraordinarily complicated question and we absolutely cannot assign specific figures, even as an approximation. There are problems over the basic definition:
-- but also problems in what we conceive literacy as meaning, culturally --
If you want a really boiled-down version of this, what it means is that in classical Greece the ability to read was relatively widespread, but it was also relatively unimportant. Education didn't mean literacy, and literacy didn't mean education. What we know of classical-era Greek education consistently emphasised oral and mnemonic abilities, and not reading/writing. No one needed literacy to live (except people who carved inscriptions for a living, and the like).
There's no hope of extracting figures from the data we have. We know literacy was widespread, but nearly all the evidence is anecdotal. But to confirm that it was indeed widespread, one piece of anecdata is the graffiti left by Greek mercenaries at Abu Simbel (Aswan, Egypt) in 593/592 BCE, which show evidence of at least nine distinct writers from a variety of places in the Greek world (Meiggs & Lewis, Greek historical inscriptions no. 7). On the other hand, the inscriptions are not copious or especially skilled: most of them are very short and simple. Were the people who wrote those ones 'literate'?
Here's a summary from a 2014 piece about Aristophanes' use of (il)literacy in a play that he staged in 414 BCE, by Carl Anderson and Keith Dix:
Those who believe that the city of Athens had achieved widespread literacy, at least by the end of the fifth century bce, have abundant evidence to support their view in Athenian drama, both in tragedy and comedy. Skeptics, on the other hand, have been able to qualify each instance of apparent reading or writing in drama so as to explain the evidence away.
That is, the lack of objectivity in the data (dramatic plays are a central piece of evidence!) means that there's no hope of reaching a quantitative answer.
We will take a different approach. We ask how Aristophanes uses literacy, or the lack thereof, to comic effect, and how his plays depict not the triumph of literacy at Athens, but rather suspicion of and resistance to it.
They illustrate this by looking at a scene in a comic play, the Birds, where two characters with an adversarial relationship claim authority for their position from a written oracle. Each makes various claims based on the scroll that they're carrying, which sounds like a nice advertisement for literacy, but whenever the other challenges a claim, the speaker simply says 'Take the scroll!' -- and they never do.
That encapsulates the kind of evidence we have. We know that there were lots of inscriptions, because we have thousands of them, and thre were lots and lots of books. But there's very often a lot of ambivalence over how these items were used. Even where someone is reading a document to themselves silently, the context uses aural/oral metaphors -- like in this excerpt from a Euripides play (Iphigeneia among the Taurians 760-763):
The things that are on the writings in the folds of the letter,
I shall tell you in speech, so that you can report everything to my friends.
For there is safety in that. If you keep the written text safe,
the writings will continue to speak silently.
I can't give an answer in relation to Roman literacy, except that I'd assume higher literacy rates and also a greater importance to reading and writing. For further reading, William Harris' Ancient literacy (Harvard, 1989) is still solid but is missing a lot of more recent developments in how we look at literacy; Rosalind Thomas' Literacy and orality in ancient Greece (Cambridge, 1992) is a fundamental text. The Anderson and Dix piece I quoted above comes from Ruth Scodel (ed.), Between orality and literacy: communication and adaptation in antiquity (Brill, 2014).