Yes to Hannah's answer above but also, if you want to use American English, you'd use periods instead of commas. 1.5

You would usually read this as "one point five years." 0.186 years would be read as "oh point one eight six years." In a special case where we recognize the decimal as a commonly-occuring fraction, we might read it that way: "one-and-a-half years." I was about to say that we only use "year" for the exact period of one year. " That isn't quite true because we also say "half a year," and "a quarter of a year." I could invent a rule for this, but I won't. As other have noted, In the US we use commas to group thousands, and decimals to separate the whole part from the decimal fraction: $1,234,567.89; so your number would be written as "1.5 years."

1,5 YEARS. And if you speak it, you'd say "one and a half years", not "one and a half year". (By the way, you can also say "a year and a half" but in your case you'll need the s.) :)

1.5 years later he decided to move on.. After a 1.5 year stay, he moved on. . I'll be back in 1.5 years. It's a 1.5 year sabatical. . At 1.5 years, she was ready to read. As a 1.5 year old she was ready to read.