Oblivion:Alchemy Calculator

The   is a tool designed to help develop potions and poisons for use in Oblivion.  It is particularly intended to help create multi-effect potions, based on the philosophy that it's always best to pack as many effects as possible into a single potion.

Nothing on the page will update until you submit your request; the page does not instantly change as soon as you make a selection.  However, hitting any submit-type button on the page will always cause all of your current selections to be processed.  In other words, you can make changes in multiple sections of the page at one time, and have them all be processed at once.

As long as you have enabled cookies, the calculator should remember any settings you have selected from one session to another.  For example, your character's settings, any customized ingredient preferences, and any recipes should be saved if you later return to use the calculator again.

Character
The inputs in this section are:
Alchemy: your character's current alchemy level.
This is the single most important input in this section, since the effects that are available will be modified based upon your character's mastery level. If you just want to explore what is possible, it is best to set this to a value of at least 75.
This value is also combined with luck to determine your modified alchemy level.  Modified alchemy determines the strength and value of all potions.
Note that this should be your character's alchemy without any fortify alchemy effects, except for the fortify alchemy provided by the Altar of Alchemy in Frostcrag Spire.  All other fortify alchemy effects have absolutely no effect on your character's alchemy abilities.

Luck: your character's current luck level
This is used to determine modified alchemy, as discussed above
This must be your character's luck attribute without any fortify luck effects.  Fortify luck effects cause no improvement in your character's alchemy abilities.

Equipment: the types and quality of alchemy equipment currently being used by your character
If you have multiple types of a given piece of equipment, provide the most powerful one here.
These are used to determine the magnitude and duration of all potions, using the equations detailed at Calculating Potion Strengths.
The app also supports the "Direnni" Alchemy equipment added by the third-party Direnni's Advanced Alchemy Apparatus Mod.

Effects
The list of available effects is determined based upon your current alchemy level (i.e., many effects are missing for novice alchemists, because it is impossible to make them at that level).  It also takes into account any ingredient preferences; for example the only way to make a silence potion at novice level is by combining the two varieties of Vampire Dust.  If quest ingredients are not being used, Silence will not be available as a novice-level effect.

The magnitude and duration shown after each ingredient are calculated based upon the values provided in the character section.  

Options:
Allow negative side-effects in potions.  If this is selected (default setting), the potions that are found may include both positive and negative effects.  Note that when requesting a poison, positive side-effects are never allowed (since any positive effects will automatically force the creation of a potion rather than a poison).
Exact matches only (no extra effects allowed).  By default, not selected.  If this is selected, no potions/poisons that provide extra effects (i.e., in addition to those requested) will be printed.
Maximum number of potions to print.  Default value: 50.  This is the target number of potions to print out.  Frequently, the actual number of printed potions will exceed this value somewhat, because of how potions are grouped in the selection process.
Maximum number of effect combinations to print. Default value: 10. This is the maximum number of  different groups of potions to print out.
Include SI and plug-in ingredients.  When checked, ingredients that have been added by Shivering Isles and Official Plug-ins (in particular, Vile Lair) will be included in potions.  Otherwise, those ingredients are considered to be unavailable.
Include rare ingredients.  Ingredients that are considered to be particularly rare (internally, done by setting F=1) will never be included in a potion; this setting is independent of the quest-specific setting.  Rare ingredients are in general those without in-game sources (i.e., no animals drop them; they are not common food; no plants or only rare plants provide them).  By default these ingredients are: Ambrosia, Beef, Cheese Wheel, Cinnabar Polypore Red Cap, Cinnabar Polypore Yellow Cap, Elf Cup Cap, Emetic Russula Cap, Ginkgo Leaf, Green Stain Shelf Cap, Ironwood Nut, Lichor, Mugwort Seeds, Root Pulp, Shepherd's Pie, Sweetcake, and Tobacco.  For SI and plug-in ingredients, Ashen Remains and Purgeblood Salts are considered rare.
If you wish to alter which ingredients are considered rare, edit the ingredient list
Include quest-specific ingredients.  By default, not selected. Ingredients tagged as quest-specific (internally, done by setting F=0) will never be included in a potion.  Quest-specific ingredients can be enabled on an individual basis by editing the ingredient list.  By default these ingredients are: Ashes of Hindaril, the second type of Bonemeal, Carrot of Seeing, Human Heart, Human Skin, Imp Fluid, Jumbo Potato, Painted Troll Fat, Pinaurus' Prized Minotaur Horn, Refined Frost Salts, Rumare Slaughterfish Scales, S'jirra's Famous Potato Bread, Unicorn Horn, and the second type of Vampire Dust.  For SI ingredients they are: Blind Watcher's Eye, Deformed Swamp Tentacle, Felldew, Greenmote, and Mute Screaming Maw.

Ingredients
This page can be used to customize which ingredients you wish to include in a potion.  Note that settings made here are remembered from session to session.  If you want to undo any previous changes you made, and restore all values to their defaults, click on "Reset Ingredients to Defaults".

This page will usually only show the ingredients that provide the requested effects.  It will show both the ingredients that are currently available and those which are unavailable given current settings.

Y(es):
Use this ingredient in EVERY potion.  At most four ingredients can have Y selected, and at that point, the calculator will only show you one recipe.  This will override any other settings (i.e., you can include a single quest ingredient by choosing Y for it).
M(aybe):
Default value.  This ingredient may be included in potions; whether it is included will depend upon the usefulness of its effects and the value of F, frequency (see below)
N(o):
This ingredient will never be included in a potion.

F(requency):
This must be an integer from 0 to 5.  The higher the value, the more likely this ingredient will be included in potions.  Ingredients with low values of frequency will only be included potions if they provide a particularly useful combination of effects.
Note that changing all values of F to 5, for example, may not have the desired effect.  The potion selection algorithms take advantage of the fact that there are a range of possible values of F.  If too many ingredients have the same value of F, the code may be forced to start randomly ignoring ingredients.

If you want to not use an ingredient
the easiest way is to click the N button next to the ingredient
you can also decrease the value under F.  If F is set to 0 or 1, the ingredient will be excluded (depending on whether quest ingredients and rare ingredients, respectively, are being used).  Low values of F will make the ingredient unlikely to be used.

Versions
Version 0.1
Original release of calculator, posted online Sept 9, 2006

Version 0.2
Posted online Sept 15, 2006.  Modifications:
Now lists one-ingredient master level potions
Problems recognizing Burden effect fixed
Problems finding all multi-effect combinations fixed
"Any two of the following" added to potion printouts
Default ingredient frequencies adjusted to account for availability of food ingredients

Version 0.3
Posted online Oct 30, 2006. Modifications:
Code updated from PHP4 to PHP5
Many PHP warnings and errors fixed
Error in which too many effects were listed for some potions (as reported by joe) has been fixed
Option to provide a printable page of recipes has been added
Direnni alchemy equipment added
Javascript validation features added
Ajax features also introduced, but only on a test basis for now

Version 0.4
Posted online May 3, 2008.  Modifications:
Added SI and plug-in ingredients
Ajax enabled by default
Fixed bug with potion magnitudes when using a Calcinator and no Retort
Added links to UESP ingredient and effect pages
Options for GET parameters in URL link added
Default ingredient frequencies all updated taking into account all possible ingredient sources
Version 0.41 (August 11, 2008): Fixed error calculating durations for duration-only negative effects (Silence, Paralyze) with a retort.
Version 0.42 (August 15, 2008): Fixed multiple errors calculating magnitudes for magnitude-only effects (i.e., Dispel)