Calculate win rate from matches.
Win rate is wins over matches played, and the treatment of draws is the choice that matters: counting them in the denominator drags the figure down, while excluding them gives the decisive win rate that ranked systems usually track. The most useful output is the third one — how many consecutive wins would lift you to a target — because it shows how heavily a large match history resists change.
Win rate
Win rate = wins / (wins + losses + draws) x 100; decisive win rate = wins / (wins + losses) x 100
Wins needed for a target
Straight wins needed = (target rate x matches played - wins) / (1 - target rate)
Because it is an average over your whole history. With 280 matches played, a single win shifts the rate by roughly a third of a percentage point, which is why sample size is the real obstacle.
Around fifty gives a rough signal and two hundred a reasonably stable one. Below about thirty, normal variance can swing the figure by ten points in either direction.