Formula Used
The calculator starts with Base Factor = Base Cost ÷ 10.
Magnitude Factor = Magnitude raised to 1.28. If magnitude is zero, the factor becomes one.
Duration Factor = duration in seconds. If duration is zero, the factor becomes one.
Area Factor = Area × 0.15. If that value is below one, the factor becomes one.
Skill Factor = 1.4 - 0.012 × School Skill. The calculator keeps it between 0.2 and 1.4.
Target spells receive a 1.5 range multiplier. Self and touch spells use one.
Effect Cost = Base Factor × Magnitude Factor × Duration Factor × Area Factor × Skill Factor × Range Factor.
Total Magicka Cost is the rounded sum of active effect costs. Gold Cost = Total Magicka Cost × 3.
Example Data Table
| Example |
Base Cost |
Skill |
Magnitude |
Duration |
Area |
Range |
Estimated Magicka |
| Fire Damage |
7.5 |
100 |
10 |
10 |
10 |
Target |
65 |
| Summon Lich |
350 |
100 |
0 |
20 |
0 |
Self |
140 |
| Shield |
0.45 |
75 |
30 |
30 |
0 |
Self |
28 |
How to Use This Calculator
Enter your spell name, current magicka, and available gold.
Activate one or more effect lines.
Choose a preset effect, or use the custom option.
Adjust base cost, school skill, magnitude, duration, area, and range.
Press Calculate Spell.
Read the result panel above the form.
Use the CSV or PDF button to save the estimate.
What This Calculator Does
Oblivion spell creation rewards planning. A strong custom spell can feel amazing, yet it can also drain magicka fast. This calculator helps you estimate that cost before you stand at an altar. You can test up to five effects. Each effect has its own base cost, magnitude, duration, area, range, and school skill. The tool then combines those values into one clear spell report.
Why Spell Planning Matters
Custom spells are flexible. You can make a cheap training spell, a long weakness setup, a burst damage spell, or a utility spell for travel. The challenge is cost scaling. Magnitude rises very quickly because it uses an exponent. Duration grows in a steadier way. Area can also multiply the price. Target spells cost more than touch or self spells. Because of this, two spells with similar results can have very different costs.
How Results Help Players
The result panel shows total magicka, gold needed, and whether your current magicka can cast the design. It also shows efficiency values. Damage and restore effects can be compared by total points per magicka. Utility spells can be judged by seconds per magicka. These quick signals help you decide whether to lower magnitude, shorten duration, remove area, or switch range.
Using Multiple Effects
Many Oblivion builds use layered effects. Weakness to Magic can prepare a target. Fire, Frost, or Shock damage can follow. A shield or feather effect can support exploration. This calculator lets you keep each effect visible. You can see the subtotal for every line, so one expensive choice is easy to spot.
Good Design Habits
Start with the real effect you want. Add only the range and area you need. Raise duration first when a steady effect is enough. Raise magnitude when the spell must hit harder right away. Compare self, touch, and target versions. Keep your school skill realistic. A high skill greatly lowers casting cost, but early characters should use smaller spells.
Final Notes
This tool gives a practical estimate for fan planning. Game quirks, mods, and remastered interface changes may alter what you see. Still, the formula view, example table, exports, and effect breakdown make spell design easier, clearer, and faster for most players today.
FAQs
What does this calculator estimate?
It estimates custom spell magicka cost, gold creation fee, casts available, school cost share, and effect subtotals. It is made for planning Oblivion spell designs before spending gold at an altar.
Can I use more than one spell effect?
Yes. You can activate up to five effect lines. Each line has its own base cost, school, skill, magnitude, duration, area, range, and role.
Why does magnitude change cost so much?
Magnitude is raised to the power of 1.28. That makes high magnitude spells grow faster in price than long duration spells. Lower magnitude with longer duration can often be cheaper.
Why do target spells cost more?
The calculator applies a 1.5 multiplier when range is set to target. Self and touch spells use a multiplier of one, so they usually cost less.
What should I enter for area?
Enter zero for no area effect. For area spells, enter the radius in feet. The formula uses area multiplied by 0.15, with a minimum factor of one.
Are the preset base costs editable?
Yes. Presets only fill starting values. You can edit base cost manually for any effect, including modded spells, remastered changes, or custom balance rules.
Why is gold cost three times magicka cost?
The calculator uses the common spellmaking rule that creation price is three times the character’s casting cost. It gives a quick fee estimate for planning.
Does this replace in-game testing?
No. It is a planning tool. Mods, patches, skill boosts, and interface quirks may change final values. Always compare important spells with the in-game altar screen.