MontePy
MontePy: A focused toolkit for editing and validating MCNP inputs—not a physics simulation engine. Ranked #60 of 89 in Physics Simulation Software by our editors (3.0/10); pricing: Free plan; best for MCNP users editing and validating input files.
At a glance
- Editor score3.0 / 10
- PricingFree plan
- Best forMCNP users editing and validating input files
- Free planYes
- Paid fromFree
- Delivery modeHybrid
- Facts checked24 Sep 2026
Where it wins
- Parses, edits, and writes MCNP input files through Python.
- Checks syntax and references, including links updated after renumbering.
- Supports parameterization and conversion to other Monte Carlo code formats.
Where it doesn't
- Does not run physics simulations or parse MCNP output files.
- Requires working with a Python package for local use.
- Its scope is MCNP input workflows, not lessons or assessment tools.
Our verdict on MontePy
MontePy is an open-source Python library for working with MCNP input files, aimed at people who need to automate or inspect model changes rather than run a simulation. It reads and parses input data such as cells, surfaces, materials, and transforms; users can edit problem objects through Python and write updated files. It is not a physics simulation engine, so teams seeking an application that directly runs broad physics simulations should look elsewhere.
Its strongest fit is input-file maintenance. MontePy checks for syntax errors and bad references, and links related objects so references update when objects are renumbered. Those capabilities support repeatable model edits and reduce manual bookkeeping in workflows that modify MCNP inputs. Parameterization can help explore modeling parameter space, while conversion to other Monte Carlo code formats may support workflows involving ORIGEN, OpenMC, or SERPENT. The library does not parse MCNP output files, which limits its role to input-side tasks.
MontePy is free and open source. It can be installed with pip or conda for local use, and browser-based Jupyter access is available for trying the library. Documentation is the listed support channel, making it a better match for users comfortable with Python and self-directed technical work than for buyers expecting guided onboarding or a graphical simulation environment. Choose it for MCNP input editing, validation, and conversion; consider another tool if you need simulation execution, output analysis, or an educational lesson and assessment product.
Your product? Our editors can test MontePy in depth and publish a review, labelled as paid · from $149/mo →
MontePy pricing
MontePy fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Delivery mode | Hybrid |
| Lesson library | No |
| Authoring tools | No |
| Assessment tools | No |
| 3D visuals | No |
| Offline access | Not verified |
| Data export | No |
| Deployment | Cloud |
| Platforms | Web |
| Support | Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 3 integrations: ORIGEN, OpenMC, SERPENT |
| Pricing | Free plan |
| Website | montepy.org |
| Facts checked | 24 Sep 2026 |
MontePy integrations
MontePy lists 3 integrations on its own site.
- ORIGEN
- OpenMC
- SERPENT
Alternatives to MontePy
- COMSOL MultiphysicsA broad desktop environment for coupled physics, engineering models, and custom simulation apps.9.4
- Ansys FluentA deep CFD and HPC environment for demanding industrial simulation work.9.3
- SimScaleA broad browser-based multiphysics platform with flexible cloud workflows and tiered access.9.1
See all MontePy alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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