Free · browser-local · 2–20 legs

Football accumulator & jackpot probability calculator

Combine your own leg probabilities, see the chance that every leg is correct, then inspect exactly or at least k correct with zero-margin fair decimal odds.

No sign-upNo booking-code lookupIndependent-leg scenarioNot betting advice

Enter each leg probability

Enter percentages from your own documented method. Do not enter a booking code or decimal odds in these probability fields.

The example uses anonymous numbers only to demonstrate the formula. They are not match forecasts, tips or real bookmaker data.

Leg 1
Leg 2
Leg 3
Leg 4
Browser-local calculationThese inputs stay in this page. No booking code, team name, account or personal data is requested.

All correct, exactly k and at least k

Results update after every leg contains a valid probability. The calculation treats the legs as independent; it does not infer dependence from fixtures, markets or booking codes.

∏pWaiting for 4 valid leg probabilities

Enter a percentage strictly between 0% and 100% for every leg, or load the labelled arithmetic example to inspect the method.

How an accumulator probability is calculated

If each leg succeeds independently with probability pi, the probability that all n legs succeed is their product: p1 × p2 × … × pn. Four 60% legs, for example, produce 0.64 = 12.96%. That is a disclosed arithmetic illustration, not a match forecast.

“Exactly k” requires more than multiplying the k largest inputs because every combination of k successes and n − k failures matters. The calculator starts with D(0) = 1 and updates the probability mass from high k to low k for each leg. This dynamic programme computes the complete Poisson-binomial distribution without enumerating 2nwin/loss combinations.

  1. All correct: ∏ pi
  2. Exactly k: D(k) after all legs are processed
  3. At least k: D(k) + D(k + 1) + … + D(n)
  4. Fair decimal odds: 1 ÷ event probability

Accumulator probability versus a booking code

A Nigeria accumulator or booking-code search often starts with an operator-specific slip identifier. That code is not itself a probability and cannot reveal whether the selections are well calibrated. This tool therefore does not accept, decode or retrieve booking codes.

Enter one probability per leg from a source whose method and timing you can inspect. If you only have a complete bookmaker market, first use the football odds implied-probability calculator to separate raw implied weights from a stated no-vig method. Do not copy decimal odds directly into a percentage field.

A saved slip is not evidence that its legs are independent.

Same-match selections, shared teams, competition context and common news can create dependence. A product of probabilities may then be too high or too low.

Kenya jackpot probability: exactly k is not at least k

Jackpot questions are often about a correct-count tier rather than every selection winning. “Exactly 12 of 15” excludes 13, 14 and 15; “at least 12 of 15” includes all four counts. The table keeps those events separate and displays a fair-odds reciprocal for each one.

Search phrases may include SportPesa or Betika. Those names are used here only to clarify the reader's query. Football Proof AI is not affiliated with, endorsed by or connected to either operator, and this calculator does not reproduce their current rules, prize tiers, booking systems or settlement decisions.

Exactly kOne correct-count outcome

Useful only when the question names a single exact tier.

At least kA cumulative tail

Includes k and every larger correct-count result.

What the offered-odds comparison means

Quoted combined decimal odds O imply the raw probability 1 ÷ O. The calculator subtracts the independent all-win probability and also reports the relative difference (1 ÷ O) ÷ P(all) − 1. A positive value means the quoted price carries more implied probability than this user-entered scenario; a negative value means less.

This is not the conventional overround of a complete market. Measuring market overround requires all mutually exclusive prices in that market. One combined price also cannot prove an edge because the entered probabilities may be wrong, dependent or measured at a different time.

What is deliberately outside this calculator

  • It does not generate selections, predictions, booking codes or jackpot entries.
  • It does not model same-game or cross-leg correlation.
  • It does not apply stake, payout, tax, bonus, boost, void, push, dead-heat or maximum-return rules.
  • It does not verify that a probability was available before kick-off or is calibrated on held-out matches.
  • Fair odds are mathematical reciprocals, not offered prices, value claims or recommendations.
Calculator output is conditional on your inputs.

A precisely computed answer can still be a poor estimate of reality when the input probabilities or independence assumption are poor. Read the responsible-use boundary before acting on football probabilities.

Accumulator and jackpot probability questions

Can this calculator read a Nigeria accumulator booking code?

No. A booking code identifies a saved selection with a particular operator; it does not disclose a trustworthy probability for each leg. Enter separately sourced leg probabilities instead. This calculator does not retrieve slips or operator accounts.

How do I calculate exactly k correct for a Kenya jackpot?

Enter one probability for each jackpot selection. The table reports every exactly-k result and each at-least-k tail. It does not know an operator's current prize tiers, settlement rules or jackpot terms.

Is multiplying the leg probabilities always valid?

Only when independence is a reasonable scenario assumption. Legs tied to the same match, team, competition, news event or market can be dependent. Multiplying them without modelling that dependence can overstate or understate the true joint probability.

Do fair decimal odds show a profitable or recommended bet?

No. Fair odds here are simply 1 divided by the calculated event probability. They contain no bookmaker margin, tax, bonus, liquidity, model uncertainty, stake advice or assurance that your input probabilities are accurate.

Formula source and next checks

  1. Hong (2013), On computing the distribution function for the Poisson binomial distribution

The cited method concerns computation for sums of independent Bernoulli trials. It does not establish that football legs are independent or validate any user-supplied probability.

Football accumulator and jackpot independent probability calculator
BROWSER TOOL · ACCUMULATOR PROBABILITYINDEPENDENT-LEG SCENARIO · NOT A WIN PROMISE OR BETTING TIP

Canonical publication record

Abstract

A deterministic browser-local calculator that combines two to twenty user-supplied football leg probabilities under an explicit independence assumption, reports the all-win product and complete Poisson-binomial exactly-k and at-least-k distribution, converts each event to zero-margin fair decimal odds and optionally compares one quoted combined price without presenting a betting recommendation, operator affiliation or prediction.

Author and publisher
Football Proof AI
Publication version
football-accumulator-probability/1.0.0
Published
Last modified
Release status
Current release
Review status
Editorial technical note; not externally peer reviewed
Production method
Editorial browser tool maintained from the declared method, linked sources and any listed reproducible artifacts.
Software and AI assistance
Software, including generative AI, may assist drafting, transformation or quality checks. It is not treated as a source, author or independent reviewer; factual and quantitative claims must remain bound to cited sources, declared methods or reproducible artifacts.
Why this exists
Enable readers to inspect assumptions, reproduce calculations and reject claims that exceed the published evidence.
Commercial boundary
No bookmaker, prediction provider or paid placement controls the evidence rules, calculations or conclusions on this page.
Version history
  1. football-accumulator-probability/1.0.0 : Initial public release.
References
  1. https://doi.org/10.1016/j.csda.2012.10.006