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Aviation · head to head

AGI STK vs simBrief

AGI STK logo

AGI STK

Aviation

Systems Tool Kit for space and aerospace analysis

From
Free
Rated
-
Full reviewWebsite
simBrief logo

simBrief

Aviation

Free online flight planning for flight simulators

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: AGI STK sTK is sold as a ladder of separate licences, STK Pro, STK Premium Air, STK Premium Space and STK Enterprise, so mission areas are gated behind different products; simBrief the free version uses a navigation database the vendor describes as slightly outdated by default
  • They diverge on capability: AGI STK covers Orbit analysis, simBrief covers Flight planning.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which AGI STK and simBrief actually diverge.

Attributes where AGI STK and simBrief differ
AttributeAGI STKsimBrief
Pricing modelsubscriptionfree
PlatformsWindows, LinuxWeb
Founded19892009

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Aviation).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in AGI STK

  • Orbit analysis
  • 4D visualization
  • Mission planning
  • Communication analysis
  • Conjunction assessment
  • MATLAB
  • Python
  • C++/.NET API

Only in simBrief

  • Flight planning
  • Weather integration
  • NOTAM analysis
  • Fuel calculation
  • Briefing generation
  • Real weather
  • NOTAM data
  • Aircraft database

What people use each for

The jobs each tool is most often brought in to do.

AGI STK

  • Modelling satellite orbits, coverage and conjunction risknot simBrief
  • Mission analysis and visualization for air, space and defence systemsnot simBrief

simBrief

  • Generating realistic flight plans and briefing packs for flight simulationnot AGI STK
  • Calculating fuel, routing and weight and balance for simulated flightsnot AGI STK

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

AGI STK

  • STK is sold as a ladder of separate licences, STK Pro, STK Premium Air, STK Premium Space and STK Enterprise, so mission areas are gated behind different products
  • Further capability is sold as separate add-on toolkits including TETK, the RF Channel Modeler and the STK Missile Toolkit
  • Distributing an application built on STK Engine to end users requires each of them to hold an Ansys STK Engine Runtime License
  • Free access is limited to students at accredited institutions and to time-limited trials
  • No price, minimum or cost driver is published for any STK tier

simBrief

  • The free version uses a navigation database the vendor describes as slightly outdated by default
  • Current navigation data updated every 28 days requires a separate Navigraph subscription
  • Jeppesen IFR and VFR charts require the higher Navigraph Unlimited subscription
  • Neither subscription price is stated on the SimBrief site, since both are sold by Navigraph

Pricing, plan by plan

AGI STK

Free
  • STK FreeFree
    • Basic analysis
    • 2D/3D visualization
    • Orbit analysis
  • STK Professional$15000/year
    • Advanced analysis
    • Premium modules
    • API access
  • STK Enterprise$50000/year
    • All modules
    • Multi-user
    • Custom solutions

simBrief

Free
  • FreeFree
    • Flight planning
    • Weather analysis
    • Fuel planning

Which should you pick?

Choose AGI STK if

  • You need orbit analysis.
  • You want to start without paying.
  • You work on Windows, Linux.
  • You also want 4d visualization.
AGI STK review

Choose simBrief if

  • You need flight planning.
  • You want to start without paying.
  • You also want weather integration.
simBrief review

Questions people ask

Is AGI STK or simBrief better?
Neither clearly leads. AGI STK starts at Free and simBrief at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, AGI STK or simBrief?
AGI STK starts at Free and simBrief at Free.
Does AGI STK or simBrief run on more platforms?
AGI STK runs on Windows, Linux. simBrief runs on Web.
Can I use AGI STK for free?
Both have a free tier, so you can try either at no cost before committing.
What is AGI STK best used for?
AGI STK is most often used for modelling satellite orbits, coverage and conjunction risk, mission analysis and visualization for air, space and defence systems. Of those, modelling satellite orbits, coverage and conjunction risk and mission analysis and visualization for air, space and defence systems are not what simBrief is typically brought in for.
What can AGI STK do that simBrief cannot?
AGI STK covers Orbit analysis, 4D visualization, Mission planning, Communication analysis. simBrief covers Flight planning, Weather integration, NOTAM analysis, Fuel calculation.

Answered from the vendors’ own pages

simBrief: Is SimBrief free to use?

Yes, SimBrief is free to use. It is a free flight planning service provided by Navigraph for Flight Simulation enthusiasts. Creating a Navigraph account is free, quick, and easy.

Source
simBrief: What does SimBrief provide for flight planning?

SimBrief is a web-based dispatching system that generates in-depth flight plan packages featuring detailed fuel planning, weather forecasts, current NOTAMs, ETOPS calculations, and much more in seconds.

Source
simBrief: Can I upgrade SimBrief for better features?

SimBrief is free by default and uses a slightly outdated navigation database. You can purchase a Navigraph subscription after registering to access the latest navigation database and additional features.

Source
simBrief: How do I access SimBrief?

To access SimBrief, you need to sign in using a Navigraph account. You can create a free Navigraph account from the SimBrief website.

Source
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