"far calmer" is correct and usable in written English.
You can use it to describe variations in a state of tranquility or peace. For example, "The lake was far calmer than usual on that sunny morning."
She's far calmer than me.
Mr. Antonoff is a far calmer and less grating singer than Fun.'s Nate Ruess.
The actual scene was far calmer, though, than the virtual one.
This reporting put the story in an appropriate perspective, far calmer than the day's television coverage.
He did, however, confirm that he'd taken up a far calmer pastime: painting and selling his artistic works on eBay.
Day visitors leave around 5pm, when and it gets far calmer – and local shops begin to close.
Shoichi Nakagawa, the finance minister, refused to comment on speculation that Japan is about to intervene to drive down the yen, saying he believed the G7 statement had so far calmed currency market volatility.
So far, calm has been restored.
12.37pm: Back to Northern Ireland, where things have far from calmed down.
In Lagos, where many firms base their regional operations, investors have so far remained calm.
So far, her calm authority, not to mention elegant English, has won her growing respect abroad.
