In your KVM dashboard (pick any VPS under services menu), you're able to see the amount of traffic this VPS used on any particular day.
We have another diagram, displaying the "Cumulative" amount of traffic since the last refill. VPS traffic counters are reset and refilled once a month (according to your product's specifications, at the product's key date).
There is a small indicator (see the red arrow below) showing how many days to go until the next traffic refill. This could be helpful to understand if you make it till the next refill or if you should top up or upgrade your plan earlier.
The red line on top represents the amount of traffic included in your plan.
Hover the mouse over a particular day to get more insights from the readings.