Table: d20-to-TD10 Conversion


The conversion table uses the ‘d20 System’ concept of the challenge rating (CR) and the OSR-style concept of hit dice (HD) to scale monsters down to Tiny d10 toughness levels, producing creatures of equivalent difficulty to their d20-based counterparts. It’s a flexible tool, and provides a general framework for well-balanced conversions while allowing game masters the freedom to adapt, adjust, or eliminate components to make as simple or complex monsters as needed.

For example, a wolf (CR1), as found in the ‘d20 System’ System Reference Document and presented in abbreviated format:

Wolf (Medium animal; 2d8 + 4 HD; Init: +2; SPD: 50ft; AC: 14; Base attack: +1; Attack: Bite (+3 melee; 1d6+1); Special attacks: Trip; Saves: FORT +5, REF +5, WILL +1; Abilities: STR 13, DEX 15, CON 15, INT 2, WIS 12, CHA 6; Skills: Hide +2, Listen +3, Move silently +3, Spot +3, Survival +1; Feats: Track, Weapon Focus; CR1).

Next, the same wolf, adapted to TD10 using the conversion table:

Wolf (T5; 5-6 HP; +1 P [10% chance]; +1 perception; fast speed; abilities: Crushing bite [inflict double damage on a natural 10]; skills: Hide).

This conversion table should serve as a functional starting-point for expanding the range of mobs and monsters that your players encounter along their journeys.

All ‘d20 System’ content used in compliance with the terms of the ‘d20 System’ Open Gaming License (OGL) v1.0a.