Tennis First Set free betting model calculator

First-Set Winner & Total Model — User Guide

What this tool does

• First-set winner: Estimates P(A wins 1st set) and fair no-vig odds for A and B.
• First-set total: Prices Over/Under a chosen first-set games line (e.g., 9.5, 10.5) with fair odds.
• Uses surface-adjusted Service Games Won% (SGW) and Return Games Won% (RGW) plus conditions and optional matchup nudges.
• Runs fast set-level Monte Carlo to account for tiebreaks and volatility.

Key inputs (what to enter)

• Preset: Choose ATP/WTA and surface to load baseline SGW/RGW and volatility.
• Surface: Hard, Clay, Grass, Indoor (affects hold rates and tiebreak likelihood).
• SGW%: Service Games Won% by surface for each player (last 12–24 months preferred).
• RGW%: Return Games Won% by surface for each player.
• Volatility proxy: Aces + double-faults per service game (higher = swingier sets).
• Conditions:
  • Altitude/Indoor boost: Faster conditions slightly increase holds.
  • Wind: Slows serves and reduces holds; shrinks tiebreak rates.
  • Injury nudge: Small adjustment toward the fitter player.
• Advanced (optional, use when confident):
  • Second-serve edges: A’s 2nd-serve points won on serve vs B’s 2nd-serve return vs 2nd (and vice versa).
  • Conversion nudge: Slight bias for returners or servers on big points.
  • Fatigue/Travel: Negative favors A (fresher A), positive favors B (fresher B).
• First-set total line: Choose 8.5, 9.5, 10.5, or 11.5.
• Book prices (optional): Enter your sportsbook odds to see value flags.

How to use it (quick workflow)

1. Pick a preset that matches tour and surface.
2. Enter or confirm SGW% and RGW% for both players (surface-specific if possible).
3. Set conditions: Altitude/Indoor and Wind; adjust Injury if relevant.
4. Optional: Add second-serve numbers, conversion nudge, and fatigue if you have solid intel.
5. Select your first-set total line (for the Total tab).
6. Click Calculate. Review:
   • First-set winner tab: P(A), P(B), and fair odds.
   • First-set total tab: P(Over), P(Under), and fair odds.
7. If you entered book prices, check the value badges (edge in probability points vs the book).

Interpreting outputs

• P(A wins 1st set): Probability A takes the opening set given inputs and conditions.
• Fair odds: No-vig American odds derived from those probabilities. Compare to book odds to judge value.
• Totals: Over means total first-set games > line (e.g., Over 9.5 hits at 10–12 games; Under at 6–9 games).
• Value badges: Show your edge in probability points (e.g., +3.2 pts means your fair probability is 3.2% higher than the book’s implied).

Best practices for inputs

• Use surface-weighted SGW/RGW from the last 12–24 months. If only overall is available, start with a preset and nudge ±1–2%.
• For second-serve stats, prefer recent surface data. If uncertain, leave advanced fields blank (the model is calibrated without them).
• Wind matters: Moderate/Strong wind often lowers Over 9.5/10.5 probabilities several points.
• Fatigue/travel: Keep adjustments modest unless you have strong evidence (e.g., back-to-back long matches, big timezone shift).

Typical scenarios and adjustments

• Big server on fast court:
  • Altitude/Indoor: Slightly faster
  • Wind: Calm
  • Expect higher P(Over 9.5) and a favorite lean on 1st-set ML.
• Return-oriented matchup on slow clay:
  • Lower Altitude/Indoor, consider Light/Moderate wind
  • Conversion nudge can be set to Favors returners (+)
  • Expect more 6–3/6–4 type sets (Under 10.5 increases).
• One player looks fatigued:
  • Use Fatigue slider toward the other player (e.g., +0.02 favors B).
  • First-set edges can swing more than full-match edges due to short format.

FAQ

• Do I need second-serve numbers? No—optional. Use them only when you’re confident; small nudges are appropriate.
• What does Volatility do? Increases set-to-set randomness and shared swings; higher with big servers or choppy conditions.
• How do tiebreaks affect totals? Higher holds increase tiebreak probability, raising Over 9.5 and especially Over 10.5/11.5.

Quality checks before betting

• Cross-check your fair odds vs multiple books’ prices.
• Sanity-check SGW/RGW against players’ typical surface profiles.
• Try a sensitivity pass: tweak wind or fatigue slightly and see if your edge persists.