---
title: hd to avg hp for osr
date: 2022-01-22
keywords: osr, dnd, rpg, hitdice, health points
---

```
hd == x
hp = floor ((hd × 8 + hd) / 2 )
```

Hydras have 8hp per HD

| hd  | hp | hydra | saves                    |
| --  | -- | ----- | -----                    |
| 0.5 | 2  |       | d 12 w 13 p 14 b 15 s 16 |
| 1   | 4  |       | d 12 w 13 p 14 b 15 s 16 |
| 2   | 9  |       | d 12 w 13 p 14 b 15 s 16 |
| 3   | 13 |       | d 12 w 13 p 14 b 15 s 16 |
| 4   | 18 |       | d 10 w 11 p 12 b 13 s 14 |
| 5   | 22 | 40    | d 10 w 11 p 12 b 13 s 14 |
| 6   | 27 | 48    | d 10 w 11 p 12 b 13 s 14 |
| 7   | 31 | 56    |                          |
| 8   | 36 | 64    |                          |
| 9   | 40 | 72    |                          |
| 10  | 45 | 80    |                          |
| 11  | 49 | 88    |                          |
| 12  | 54 | 96    |                          |
| 15  | 67 |       |                          |