🏸 Badminton Elo · starts at 1000
The familiar Elo system from chess, plus a margin factor so a big win counts for more than a narrow one.
Δ = K × M × (S − E)
E = 1 / (1 + 10^((opponent's Elo − your Elo) / 400))
M = 1 + min(total point difference, 30) / 60
- S = 1 for a win, 0 for a loss. K = 32 (K = 48 for your first 10 matches).
- Doubles: uses the pair's average Elo, and both partners get the same Δ.
- Best of 3 games, each to 21 points, win by 2, capped at 30.
🐣 Newbie <1100🐥 Rookie 1100+🐓 Contender 1250+🔥 Ace 1450+⭐ Superstar 1650+👑 Legend 1850+
You 1486 vs 1576Won 21–15, 21–18
Expected win probability37%
Change+27 / −27
🏓 Pickleball Rating 2,00 – 8,00
A DUPR-style scale. Wins always add, losses always subtract; the score decides how much you gain or lose.
Δ = 0,2 × (S − E) × M
S = 1 for a win, 0 for a loss
E = expected win probability = 1 / (1 + 10^((opponent's rating − your rating) / 1.2))
M = score factor = 1 ± 3 × (A − E), limited to 0.4 – 1.6 · A = points you scored / total points in the match
- Games to 11 points, win by 2; win 2 games to take the match.
- Beat a stronger player and you gain more; win by more than expected and you gain extra.
- A close loss to a stronger player costs very little.
- Singles and doubles ratings are tracked separately.
🐣 Newbie <3.0🐥 Rookie 3.0+🐓 Contender 3.5+🔥 Ace 4.0+⭐ Superstar 4.5+👑 Legend 5.0+
You 3.85 vs 4.30Lost 9–11, 11–9, 10–12
Expected win / points share30% / 48%
Change−0.03
🎾 Tennis Rating 1,00 – 16,50
A UTR-style scale. Wins always add, losses always subtract; the share of games you win decides how much you gain or lose.
Δ = 0,2 × (S − E) × M
S = 1 for a win, 0 for a loss
E = expected win probability = 0.5 + 0.08 × (your rating − opponent's rating) (limited to 5%–95%)
M = score factor = 1 ± 3 × (A − E), limited to 0.4 – 1.6 · A = games you won / total games
- Beat a stronger player and you gain more; a close loss to a stronger player costs little.
- If a match is abandoned partway, only the games played count.
- Singles and doubles ratings are tracked separately.
🐣 Newbie <4🐥 Rookie 4+🐓 Contender 6+🔥 Ace 8+⭐ Superstar 10+👑 Legend 12+
You 6.42 vs 7.10Won 6–4, 7–5
Expected win / games won45% / 59%
Change+0.16
🏐 Volleyball Team Elo · starts at 1000
Ratings belong to the team. Like badminton, it's based on sets won, and winning by a bigger point margin earns more.
Δ = 30 × M × (S − E)
S = 1 win · 0 loss (no draws in volleyball)
M = 1 + min(total point difference, 40) / 80, from 1.0 to 1.5
- Sets to 25 points, deciding set to 15, win by 2 with no point cap.
- Indoor 6-a-side, air volleyball and beach volleyball all share one team Elo table.
- Ratings move faster over the first 10 matches so new teams quickly settle at their true level.
🐣 Newbie <1050🐥 Rookie 1050+🐓 Contender 1200+🔥 Ace 1350+⭐ Superstar 1500+👑 Legend 1650+
Team Cầu Giấy 1120 vs 1180Won 2–1 (25–22, 20–25, 15–12)
Margin factor1,04
Change+18 / −18
⛳ Golf Handicap Index · lower is better
Based on the World Handicap System (WHS). Head-to-head matches compare net scores, so players of any level can compete fairly.
Differential = (113 / Slope) × (gross score − Course Rating)
Handicap Index = average of the best 8 differentials from your last 20 rounds
Net score = gross score − Course Handicap (Course Handicap = HI × Slope / 113)
- You need at least 3 rounds of 18 holes for an official HI.
- Local rankings go by HI; ties are broken by rounds played this season.
- Pairs and groups of 4 are ranked by matches won on net score.
🐣 Newbie >32🐥 Rookie ≤32🐓 Contender ≤22🔥 Ace ≤14⭐ Superstar ≤8👑 Legend ≤3
You HI 14.2 vs HI 8.684 – 79 strokes
Net score68 – 69 → you win
Your HI14.2 → 13.8
General rules
- Two-sided confirmation: a result only counts once both sides confirm. If there's no response within 48 hours, it's finalized automatically.
- Ranked and friendly matches: the host decides whether the match counts toward ratings.
- Calibration period: your rating moves faster over your first 10 matches to reach your true level.
- Inactivity: after 60 days without playing, you're temporarily hidden from the leaderboard (your rating is kept).
- Repeat limit: against the same opponent, only 3 matches a week count toward your rating, to prevent "rating farming".
🥚 Unhatched egg: no confirmed matches yet, so your rating is just a starting point. Play your first match to "hatch" into one of 6 tiers: 🐣 Newbie → 🐥 Rookie → 🐓 Contender → 🔥 Ace → ⭐ Superstar → 👑 Legend.
Local rankings
- Everyone has one rating per sport, used at every level: ward → district → city → nationwide.
- Your area is where you've played most in the last 30 days, not where you signed up.
- Each season lasts 3 months. Top 1/10/100 badges are awarded at the end of the season, and ratings carry over to the next one.
Anti-cheating
- Ratings are calculated by Kèo from the score and both sides' current ratings — nobody can enter their own points.
- Both sides must confirm before ratings change. You can't log a result against yourself or confirm your own result.
- Rematches with the same opponent within 7 days: the 2nd match counts 50%, the 3rd counts 25%, and from the 4th on they don't count. To climb, play lots of different people.
- Opponent is a new account (under 3 days old or fewer than 3 matches): points gained are halved.
- Each account can log up to 20 results a day.
- The system automatically flags unusual matches (one player beating the same opponent again and again, identical repeated scores, confirmations just seconds after submitting…) for the support team to review.
- Players can report wrong scores; the support team reviews them within 72 hours.
- Rating floor: after 10 matches, your rating can't fall more than a set amount below your all-time best (badminton and football: 100 Elo; pickleball: 0.2; tennis: 0.5; golf: HI can't rise more than 3 above your best). A losing streak won't wipe out all your hard work.
- ✓ Verified: accounts with 10+ confirmed matches against at least 5 different opponents and no rating lock.
- Violations: the result is voided and points are reversed, and your ranking is locked for 30 days (you can still play and create games as usual). Repeat offenders have their accounts suspended.
Parameters (K, the margin factor, tier thresholds) may be fine-tuned based on real data. Any changes will be announced before the season starts.