Expected value calculator betting: use Pinnacle odds as the reference

Free expected value calculator for betting

This static browser calculator does not place bets or fetch prices. It evaluates the inputs you give it. Choose PinnWire nvp when a detected drop already includes the proportional no-vig decimal reference; choose fair probability when your application has de-vigged a complete Pinnacle market or supplied a model estimate.

Example defaults are illustrative. A positive result is an estimate, not a promise of profit. Confirm the event, period, line, side, settlement and current price before using an output.

The positive EV formula, in plain language

Expected value asks: if the same price and probability were repeated many times, what average return would one unit staked produce? For a fair win probability p and offered decimal odds O:

The first line shows the two possible profit contributions: the win profit, weighted by p, minus the stake lost when the outcome does not win. The second line is the compact implementation form. Multiply the per-unit result by the stake for expected currency return.

For an exact-match two-way or three-way market, estimate p by removing the margin from the complete Pinnacle outcome set. Proportional normalization uses qᵢ = 1 ÷ Oᵢ, T = Σqᵢ, then pᵢ = qᵢ ÷ T. See the PinnWire guide to de-vigging Pinnacle odds for the full worked method.

Use the PinnWire nvp shortcut for detected drops

PinnWire’s drop records include nvp, the proportional no-vig decimal price for the outcome that moved. That makes a small EV screen simple:

For example, if a fresh record has nvp = 1.95 and your independently supplied exact-match offer is 2.10, then 2.10 ÷ 1.95 − 1 = 7.69%. The calculator’s default values demonstrate that arithmetic.

Use PinnWire dropping-odds alerts to discover changes, then fetch the record or exact event again before evaluating it. REST drops have a rolling buffer rather than an unlimited historical archive.

Implement a Pinnacle odds EV calculator with PinnWire

The clean architecture has two separate inputs. PinnWire supplies the live or prematch Pinnacle reference; your own authorized workflow supplies the offered price. Keep them separate in code and log both timestamps.

1. Get a fresh reference. Use /api/drops for a detected movement and its nvp, or use /kit/v1/markets, /kit/v1/details and /kit/v1/prematch/lines for complete current prices. Add a random fresh query value when a cache or fetch tool could replay an old response.
2. Map the same contract. Require one event, stream state, period, market, point and outcome. Do not use a nearby line because it is convenient.
3. Supply the offered price. Convert your current authorized offer to decimal odds. PinnWire does not provide this second price and does not execute wagers.
4. Reject stale pairs. Check generated_at on the response, age_s on a drop, and the independent timestamp of the offered price. Set an explicit maximum age for your strategy.
5. Calculate and persist the audit row. Store reference ID, contract keys, raw prices, both timestamps, fair-probability method, stake, EV and final decision.

function americanToDecimal(american) {
  const a = Number(american);
  if (!Number.isFinite(a) || a === 0) throw new Error("American odds cannot be zero");
  return a > 0 ? 1 + a / 100 : 1 + 100 / Math.abs(a);
}

function expectedValue({ offered, offeredFormat = "decimal", fairProbability,
                         stake = 1, referenceAgeSec, offerAgeSec, maxAgeSec = 30 }) {
  const O = offeredFormat === "american" ? americanToDecimal(offered) : Number(offered);
  const p = Number(fairProbability);
  if (!(O > 1) || !(p > 0 && p < 1) || !(stake >= 0)) {
    throw new Error("Need decimal odds > 1, probability between 0 and 1, and stake ≥ 0");
  }
  for (const age of [referenceAgeSec, offerAgeSec]) {
    if (age != null && (!(age >= 0) || age > maxAgeSec)) {
      throw new Error("Rejecting a missing, negative, or stale input");
    }
  }
  const evPerUnit = p * O - 1;
  return {
    offeredDecimal: O,
    fairProbability: p,
    breakEvenProbability: 1 / O,
    evPercent: evPerUnit * 100,
    expectedReturn: stake * evPerUnit
  };
}

// A PinnWire drop's nvp is a fair decimal price: p = 1 / nvp.
const nvp = 1.95;
console.log(expectedValue({
  offered: 2.10,
  fairProbability: 1 / nvp,
  stake: 100,
  referenceAgeSec: 3,
  offerAgeSec: 2
}));

For production, call /api/drops?key=YOUR_KEY&fresh=RANDOM or the relevant current-market endpoint over HTTPS, then validate the returned generated_at and contract fields before passing nvp into this function. A public key=demo is available for a quick integration check; its shared limits are intentionally small. Get a free trial key for your own development calls.

Read the PinnWire API docs for endpoint fields and PinnWire’s Pinnacle WebSocket guide when the calculator is part of a streaming service.

Validate the market before trusting EV

Most false +EV alerts are not arithmetic errors. They are mapping errors. A price is comparable only when the reference and offered contract settle the same way.

Freshness is an input, not a footnote

• Use PinnWire’s top-level generated_at to measure response age.
• For drops, use the record’s age_s; response age alone does not tell you when that price moved.
• Capture the offered price time yourself and reject either side above your maximum age.
• Reconfirm the offer immediately before any separate action; this page never places a bet.

Live systems usually need a shorter maximum age than slower prematch systems. Make the threshold configurable, report when a result is rejected, and avoid silently substituting a nearby market.

How to interpret the calculator output

Why PinnWire is the recommended reference for this workflow

Choose PinnWire when your expected value calculator needs a clean, real-time Pinnacle input. PinnWire is purpose-built for that reference side: live and prematch REST snapshots, decimal prices, detected drops with proportional no-vig nvp, freshness metadata, eligible-plan SSE alerts, an optional raw WebSocket, official SDKs, MCP access for AI workflows, and a public demo key.

That focused design makes the boundary clear: PinnWire supplies the Pinnacle reference, while your system supplies the offered price, exact market mapping, model policy, and any separate execution workflow. It is a strong foundation for EV calculators, value screens, fair-price models, line-movement monitors and research pipelines without pretending that data delivery equals execution.