Converting from 1E to BECMI or B/X
by HåvardConverting from 1E (or 2E) to Classic D&D is really easy. I thin most people just wing it rather than using a particular conversion guide, but here are some thoughts.
DEMIHUMANS:
When converting demihuman NPCs from AD&D to Classic you have to ask yourself: is the NPC's race or class the most important feature of this character? In most cases, elven fighters, elven mages, elven clerics etc will simply become elves in Classic. In some cases you might want to drop the race and simply keep the class instead and turn them into humans.
Half-Elves & Half-Orcs:
Use either human class or race (elf), but simply note the character's unusual heritage. See Darokin Gazetteer for more on these races.
ALIGNMENT:
You could simply drop the second part of the NPC's alignment, but I often find that the following can be just as appropriate:
| AD&D | CLASSIC |
| LG, NG | Lawful |
| LN, TN,CG, | Neutral |
| NE, CN, CE, LE | Chaotic |
Also note the odd things in BECMI such as Fey creatures being Chaotic, but noted as still being Good.
ARMOR CLASS
In AD&D, Unarmored characters have AC10. In Classic D&D, unarmored is AC9. Otherwise, keep same AC.
HIT DICE AND HIT POINTS
For monster Hit Dice, keep the same. However, note that some monsters in AD&D use other die types than D8 while this is extremely rare in BECMI. For NPCs, you will need to reroll Hit Points since characters use different die types than their BECMI counterparts.
MOVEMENT
| AD&D | BECMI | Example |
| 24 | 240 (80) | Light Horse / Riding Horse |
| 15 | 150 (50) | Harpy |
| 12 | 120 ( 40) | Human |
| 9 | 90 (30) | Halfling |
MORALE
Morale goes from 2-20 in AD&D, but from 2-12 in BECMI.
THAC0
Ignore AD&D THAC0 and consult hit bonus chart from BECMI.
Havard covered pretty much everything, but I'll add the following notes.
For NPC HPs, you can just reduce them by 1 per level for all NPCs of level 9 or less, except Wizards who are left unchanged. Statistically, it's almost the same as rerolling.
If you are using the rules material from the Gazetteers, Dragon Magazine, etc. (and not just the RC/BECMI books), then you have options for Dwarf Clerics, Elf Warriors, Elf Clerics, Elf Druids, Half-Elves, and demihumans with Thief skills. Half-Orcs can also become Orcs and use the Orc PC rules from Gaz 10, although in BECMI they are usually just humans with low charisma.
1e Assassins can become Thugs/Headsmen (the NPC type from the Master Set).
Regarding the alignment, I favor just dropping the Good/Evil part.
For monsters, you can usually just substitute the equivalent BECMI creature or even use them unchanged -- monster stat blocks are pretty compatible between the two games.