Praetorium

Praetorium is a free, open source Warhammer 40,000 army builder, combat simulator and battle tracker. Ask Claude about any faction's units, points, detachments, enhancements, stratagems and missions, and get answers with links to the matching Praetorium page. Compare two units with Praetorium's combat simulator to see expected casualties and the odds of destroying the target. Sign in with your Praetorium account to read your saved rosters and battles, build or edit a roster, create a battle, or record a battle action. Praetorium returns names, numbers, points and calculated results, not rules text: when an answer depends on a rule's wording, it links to the published source instead. Reference lookups and the simulator work without an account; roster and battle tools ask you to sign in, with read and change access granted separately. Praetorium is unofficial and not affiliated with or endorsed by Games Workshop.