It should be pretty straightforward to check the alcohol level in your wine. You just look at the label. But it is not that simple. Maybe there is more than the label states. Or less. This is because the producers have a certain flexibility regarding what they choose to put on the label.
The EU allows a margin of error of 0.5%. If one’s wine is analysed to have an alcohol content of, say, 13.7 or 13.9%, the producer can choose to write 13.5% or 14% on the label, depending on what they think will sell best. According to the rules, the figure must be rounded to the nearest half or whole percent (which they don’t always do).
The USA is even more tolerant, allowing a margin of error of 1% for wines that are over 14%, and for wines at 14% or less, a whopping 1.5% leeway is allowed. Depending on what you think your customers want you can choose to go lower or higher on the label.
Even if some people today chase low alcohol levels, there are others who want powerful wines which they associate with high alcohol.
Perhaps it would be better to be guided by the taste instead?