BREAK-EVEN

How to Calculate Break-Even Price in a Polymarket BTC 5-Minute Market

A practical guide to entry cost, shares, fees, settlement payout and break-even probability in a Polymarket BTC 5-minute market.

DIRECT ANSWER

The short answer

For a winning binary outcome that pays one dollar per share, break-even depends on the total amount paid to acquire the position, including execution across depth and applicable fees. A simple per-share break-even cost is total acquisition cost divided by filled shares. The corresponding required win rate is derived from that cost, but it is not a prediction of the next round.

Evidence boundary: official documentation establishes platform mechanics and source behavior; calculations, examples and interpretations are PolyCerno Research analysis. They do not guarantee an outcome or profit.

Primary referencesPolymarket prices and order bookPolymarket resolution documentationPolymarket fee documentation
WORKING DEFINITIONS

Terms used in this guide

Break-even cost
The average total acquisition cost per filled winning share under the modeled payout.
Required win rate
The long-run success frequency needed to offset the modeled average cost under simplified assumptions.
Filled shares
The quantity actually obtainable or executed, excluding unfilled requested size.

Begin with the binary payout

Under the governing market rules, a winning outcome token is redeemable for the specified settlement value and a losing token is worth zero. The exact rule and any exceptional condition must be verified for the individual market.

For a fully filled position, the maximum settlement receipt is determined by the number of winning shares held. The amount originally intended is not the payout.

The simple break-even relationship

Break-even probabilitytotal acquisition cost ÷ potential winning payout

If 100 shares produce a 100U winning payout and the total acquisition cost is 63U, the simplified break-even probability is 63%. That is a threshold, not a forecast: the trade has positive expected value only if the trader’s well-supported probability estimate exceeds the full break-even requirement.

Replace displayed price with real acquisition cost

The displayed price may be a midpoint or last trade. A buyer pays available asks, possibly across several levels. Add current fee treatment and use only the shares supported by modeled liquidity.

ILLUSTRATIVE POSITION100U intended · 96.4 shares received · 63.8U total cost

The potential winning receipt is 96.4U, so the relevant threshold is 63.8 divided by 96.4—not the first ask shown before the order was modeled.

Partial fills change the denominator

If only part of the intended order can execute, both cost and payout change. A tool should not pretend the missing shares were filled at the final visible price. Report the completed portion, unfilled portion and resulting payout separately.

When several fills occur over time, aggregate actual shares and actual paid amount. Do not average percentages without weighting them by size.

Break-even is not the same as market probability

Contract price is commonly read as implied probability, but liquidity and execution conditions create a gap between the displayed value and an individual trader’s required win rate. Break-even is personal to the modeled entry; the market price is a public state.

Neither value proves the true chance of resolution. Directional evidence, data quality and reversal risk still need independent evaluation.

Use break-even as a decision boundary

  1. Verify the market and settlement payout.
  2. Model the intended order against current depth.
  3. Add fees and confirmed costs.
  4. Calculate actual shares and maximum winning receipt.
  5. Compute the break-even threshold.
  6. Compare it with the evidence-based case, including uncertainty.
  7. Reject the entry when the margin is too small or the inputs are stale.

Sources and further reading

Primary documentation was checked on . Source interfaces and market rules can change; verify the current market before relying on a field.

  1. Polymarket prices and order book
  2. Polymarket resolution documentation
  3. Polymarket fee documentation
  4. Polymarket order-book API
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