Overshove
Start free
Calculator

Poker downswing calculator

Updated October 2026 · by Tom Howcroft

Calculate a positive-edge model drawdown scale from win rate and standard deviation. See the assumptions, big blinds and buy-ins, without a maximum-loss claim.

What does this result mean?

A poker downswing calculator estimates the scale of a normal drawdown for a player with a given win rate and standard deviation. A thin edge and volatile results create deeper losing stretches, even when the player remains a long-term winner. The output is best read as an order-of-magnitude planning figure, not a maximum loss or a prediction of the next downswing. Real paths can be shorter, longer or interrupted by recovery.

Use conservative inputs from the game you actually play and compare the result with your bankroll, stop rules and emotional limits before a bad run starts. If a live downswing falls inside the model, keep logging and review the decisions rather than assuming the result proves a leak. If repeated hand evidence points to mistakes, fix those mistakes even when the drawdown itself is statistically ordinary.

4
90
10.1 buy-ins
Drawdown scale (model)
1,012.5
In big blinds
Next step

Keep a record through the downswings

Your estimated normal drawdown is a guide based on the edge and swings you entered. Record real sessions in Overshove so you have a history to review when a downswing tests those assumptions.

Start a free log of your sessions

The app opens in a new tab. On the sign-in screen, choose "New here? Create an account". Calculator numbers are not transferred to the app. Enter your real session records there to start your log.

Tracking and calculations do not guarantee a profit or prevent losses.

A positive-edge Brownian model gives a characteristic drawdown scale from volatility squared divided by twice the edge. It does not predict a maximum downswing.

Example

At 4 BB/100 and a 90 BB standard deviation per 100-hand block, the Brownian drawdown scale is 1,012.5 BB, or 10.125 buy-ins of 100 BB. It does not bound a future peak-to-trough loss.

Estimates for study and planning only, not a profit promise. Overshove tracks your real sample so these inputs come from your own data.

What does this calculator compute?

The positive-drift Brownian model uses volatility squared divided by twice the edge. This is the expected all-time loss below the initial balance in that model, not maximum drawdown from future peaks.

When should the result change your decision?

Use it before deciding a losing spell means the game is broken. A normal downswing still needs review, but it should not automatically trigger a stake jump, panic drop or revenge session.

How to use the answer responsibly

Treat the calculator as a planning tool, not a verdict on one session. A live poker input is usually an estimate: your win rate is noisy, your standard deviation changes by game type, and your future volume rarely matches the clean number you type into a form. The useful habit is to save the assumptions beside the result so you know what would need to change before the decision changes.

If the result pushes against what you wanted to do, do not smooth the inputs until the answer feels nicer. Make the conservative version first, using a lower win rate, a higher swing rate or fewer weekly hours. Then run the optimistic version. The space between those answers is the real decision area: where a shot needs a stop rule, where a move up needs more buy-ins, or where a good-looking hourly still needs a bigger sample.

Overshove calculators become more useful when the inputs come from your own logged sessions. Rake, tips, travel, hours, stake mix and session length all change the number. A generic benchmark can teach the shape of the problem, but a clean personal log gives the number you should actually act on.

Questions

Is this the maximum downswing I can expect?

No. Volatility squared divided by twice a positive edge is the expected all-time loss below the initial balance under a fixed Brownian model. Drawdowns from future peaks depend on the horizon and can be larger.

Does a downswing prove poor play?

Results alone do not identify the cause. Review decisions and the assumptions as well as the size of the loss.