2020-02 HRC Update: Monte Carlo and MTT ICM

A major HRC update is now available for download. This release includes a new Monte Carlo calculation engine, an improved Multi Table ICM mode and various user interface changes.


  • New Monte Carlo Mode: Supports card bunching and up to 10 active players.
  • New MTT functionality: The MTT user interface and the calculation model have been re-written from scratch. ICM calculations for large tournament fields have significantly improved accuracy in the new version.
  • New user interface for the hand setup dialogs, range editor and hand grid. Most new components come with tooltips, simply hover your mouse over a setting to display a short help text. The range edit dialog now supports editing via mouse drag and mouse wheel.
  • New tool to edit and manage custom prize structures at Tools: Structure Manager.
  • Fix for OSX related compatibility issues. The new version works out of the box on OSX systems, including the latest OSX Catalina.
  • Update to Java 13. HRC now comes bundled with a compatible OpenJDK runtime on all platforms and has the option to upgrade its Java runtime through the auto-update feature. No additional Java runtime is required.


This version includes major upgrades of the program framework and unfortunately some of these changes can not be rolled out via the existing auto-update functionality. You can download the new installer from the download section.

To import custom prize structures from older installations, please check the Upgrade Instructions below.

Main Features

Updated range editor

The range edit dialog has been updated to allow faster editing:

  • Left click to select individual hands
  • Right click to select hands of the same row or column
  • Hold left mouse button to select multiple hands
  • Mouse wheel to adjust mixed strategies

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New MTT ICM mode

The user interface and the calculation model for multi table ICM calculations have been completely re-written. The new model provides equity estimates that are essentially as good as a full 'Malmuth-Harville' ICM calculation, even for fields with thousands of remaining players. Detailed information about the accuracy of the new model, including a comparison to the old MTT model, can be found here: High Accuracy ICM Calculations for Large Fields.


To setup MTT calculations with the new model:

  • Select "MTT ICM" as equity model on the first page of the setup dialog, choose bounty options as usual.
  • Enter the prize structure on the right side of that page. Repeated prizes can be skipped, entering the prize jumps is sufficient. (e.g.: entering 10th = 10$, 15th = 5$ will assume that 10th-14th all pay 10$)
  • Click Next and use the top button on the MTT dialog page to generate stacks on other tables, input total chips and number of players as needed. (If a chip total is entered on the first page, then HRC will estimate the number of remaining players based on the active stacks.)
  • Check the summary table for the generated stacks to make sure everything is correct. Done.

Note regarding PKO bounties: By default, HRC assumes that the average bounty in the tournament is equal to the average bounty on the active table. The average bounty on the other tables can be manually specified on the MTT dialog page.

Monte Carlo mode

The Monte Carlo mode adds a second calculation engine to HRC, besides the classic Math / Enumeration mode. It is especially useful for spots where more than 3 players might be actively involved in the pot. It also supports card bunching, which is mainly significant for strategies of the later positions when folded to on a full table. The Monte Carlo engine quickly produces accurate results for the main lines, even in large calculation setups. On the downside, EVs for lines that are played out infrequently will converge very slowly.


There is a new entry in the Home tab to start a Monte Carlo Hand setup. The setup itself is mostly identical to a regular "Basic Hand Setup", the only difference is an additional setting on the first dialog page where the maximum number of active players can be specified (default is 3). Interaction with the calculated hand is also largely unchanged. The main difference is that the Monte Carlo mode does not automatically update EVs when ranges are manually changed.

The Run Nash Calculation feature (green button in the toolbar) can be used to run additional sampling, e.g. to update EVs after changing ranges. The Reset option clears all previously sampled EVs, this is useful if big changes were made to the strategies. Updates can be done either to the entire hand (default), or only to a selected part of the game tree. The latter option is much faster (up to around 20x) and is useful to speed up sampling when looking at infrequently played lines.


Classic Math EngineMonte Carlo Engine
EV displayAlways up-to-dateOnly updated upon additional sampling
Reproducible EVsYesSubject to sampling error
Max. active players32-10
Active card removalYesYes
Folded card removal
(i.e. card bunching)
Advanced plotsYesNo
Nash Distance

Key differences

  • The Math engine displays EVs based on full run-outs over all boards and all opponent hands. The displayed EVs are perfectly reproducible if the defined strategies are the same. The Monte Carlo mode estimates EVs by sampling random hands, the displayed EVs include randomness from sampling, i.e. a sampling error. This is especially significant for infrequently played lines where sample sizes may be very small.
  • The Math engine always displays up-to-date EVs against the specified strategies, upon changing a range the EVs of other ranges are automatically updated. (Note that the other ranges are not automatically updated, only their EVs.) The Monte Carlo mode does not update EVs unless additional sampling is done.
  • To allow efficient calculation, the Math engine restricts the calculated game: No more than 3 active players are allowed, and passive card removal is not considered (i.e. card removal from folded ranges). The Monte Carlo mode supports up to 10 active players and considers all card removal effects.
  • The Math engine displays the Nash distance (Exploit%) in the Outline area. This measures the distance of the current (unlocked) ranges to a Nash Equilibrium, in a true Nash Equilibrium all Exploit% values are zero. Nash distance calculations are not available in Monte Carlo mode.

Limitations and known issues

  • When using FGS with the Monte Carlo mode, any lines with >3 players in the pot are calculated using regular ICM.

  • Advanced Hands using the Monte Carlo mode still only support a maximum of two consecutive limps or flat calls. This is a limitation of the betting setup UI and not a principal restriction in the Monte Carlo engine.

  • Both the Math / Monte Carlo engines consider all possible outcomes of a pot, dealing correctly with potential ties and side pots. Allowing more than three active players drastically increases the number of possible outcomes, which also means that the equity model needs to be invoked more often. Typically this isn't noticeable, but when using Monte Carlo with a high setting for max. active players in combination with the MTT ICM equity mode with large player fields this can lead to slow initialization times.

Upgrade Instructions

The new version uses a different format to store custom prize structures. If you wish to import your custom structures from the previous stable version then follow the instructions below:

  1. Locate the net.holdemresources.calculator.prefs file from your old HRC installation and copy it to an easy-to-find location. This file can be found in the following location within the installation directory:

    HRC / workspace / .metadata / .plugins / org.eclipse.core.runtime / .settings

  2. Install the new HRC version and go to Tools: Manage Structures.

  3. Use the import option from the toolbar and select the .prefs file you saved in step 1.

  4. The prize structures will now be available in a new Imported category.

  5. Optionally create new categories from the toolbar and drag / drop structures to re-organize them.

  6. Finally save the changes. Your imported structures will now show up in the custom structures menu.

Discontinued features

  • The Game Tree tab has been deactivated due to issues with the graph library used. The feature appeared to see little use in practice, but depending on user feedback it may be added back at a later time.
  • SQL import from HM1 and PT3 are permanently removed, these options have been obsolete for some time.

Legacy version for 32-bit systems

Starting with this version HRC will no longer support 32-bit systems. Downloads of a legacy HRC version with 32-bit support will remain online in the download section until the end of 2020. We will release occasional updates to maintain hand history support, but the legacy version will not receive any feature updates going forward and it will eventually be discontinued entirely.


The HRC Support Thread on 2+2 is the best option for general questions, feedback and discussions of new features.

Preferably contact support@holdemresources.net with bug reports or issues that may be related to your specific hardware setup. In these cases please try to include the steps necessary to reproduce the problem and ideally mention any special properties of your computer setup that might affect the issue.