A World of Warcraft Classic Era addon that adds spell power coefficients to spell tooltips, so you can see how much of your +damage or +healing a given spell and rank actually uses.

Hover any spell in your spellbook, on an action bar, or in a chat link:

Flash Heal (Rank 1)
  Spell power coefficient
    Direct                                  0.429
      +300 from 700 healing power

• Direct — the coefficient applied on impact.
• Over time (total) — the coefficient spread across the whole periodic effect, not per tick.
• Channel (total) — the coefficient for a full channel.
• Hybrid spells such as Immolate or Regrowth list both components separately.

A ~ in front of a value means it was derived from the base formulas rather than taken from known spell data.

1. Download or clone this repository.
2. Copy the folder into World of Warcraft/_classic_era_/Interface/AddOns/, named SpellCoeffsForever.
3. Restart the game, or run /reload if it is already running.

The folder name must match the .toc file name for the client to load it.

/spellcoeffs works as an alias.

Classic Era derives most coefficients from two base formulas:

Cast times are read from the client for the exact rank being hovered, with the usual 1.5 second floor, so downranked spells are handled correctly. Periodic durations, hybrid splits, and the spells Blizzard tuned away from the formula live in Data.lua.

One penalty is applied on top: spells whose own level is below 20 lose 3.75% of their scaling per level below 20, so a level 1 rank keeps 28.75%. Classic Era does not have the level-based downranking penalty introduced in The Burning Crusade, so no such penalty is applied here.

Every game API the addon reads goes through Compat.lua, which prefers the C_Spell and C_AddOns namespaces used by current clients and falls back to the old globals. When an API is missing entirely the accessor returns nothing and the affected line is simply left out.

Two limitations are worth knowing:

• The client does not expose a spell's school in Classic, so the gear-adjusted line uses your highest school bonus for damage spells.
• Area spells were tuned individually in vanilla, so their values are marked as estimates.

The refinements in Data.lua are keyed by English spell names. On other locales the formulas still apply, but those per-spell corrections are skipped.