Modifying Spells

The enhancements and limitations allowed for spells are listed below. Where possible, page references have been given. In all cases, the modifier desired should be thoroughly investigated before being applied to the new spell. Where page references are not available, refer to the GM for details.


  • Accurate, +5%/level [B102, P99]
  • Affects Insubstantial (Selective), +30% [B102, P99]
  • Affects Insubstantial, +20% [B102, P99]
  • Affects Substantial (Selective), +50% [B102, P99]
  • Affects Substantial, +40% [B102, P99]
  • Area Effect, +50% [B102, P100]
    Only 1 level allowed, to convert a normal spell into an area effect spell, changing standard cost into base cost.
  • Armor Divisor, +50%/level [B102, P100]
    Levels are (2), (3), (5), and (10). Taking levels above 4 only offsets any Hardened levels the armor may have.
  • Aura,+80% [B102, P100]
  • Based on (Different Attribute), +20% [B102, P100]
    Note that this applies to the Resistance roll for the spell.
  • Can Carry Objects, Variable [P108]
  • Cone, Variable [B103, P100]
  • Contact Agent, +150% [B103, P101]
  • Cosmic, Variable [B103, P101]
    Not all Cosmic enhancements are available.
  • Cyclic, Variable [B103, P101]
    Note that this is available for more than just attacks, it converts any Instant spell into a Regular spell with a duration. The most obvious example would be Minor Healing, where a single cast spell allows the subject to heal a greater volume over a longer span of time.
  • Damage Modifiers: Double Blunt Trauma (dbt), +20% [B104]
  • Damage Modifiers: Double Knockback (dkb), +20% [B104, P101]
  • Damage Modifiers: Explosion (exp), +50%/level [B104]
  • Damage Modifiers: Fragmentation (frag), +15% per die [B104, P102]
  • Damage Modifiers: Hazard (Dehydration), +20% [B104]
  • Damage Modifiers: Hazard (Drowning), +0% [B104]
  • Damage Modifiers: Hazard (Freezing), +20% [B104]
  • Damage Modifiers: Hazard (Missed Sleep), +50% [B104]
  • Damage Modifiers: Hazard (Starvation), +40% [B104]
  • Damage Modifiers: Hazard (Suffocation), +0% [B104]
  • Damage Modifiers: Incendiary (inc), +10% [B105, P102]
  • Damage Modifiers: Radiation (rad), +25% or +100% [B105, P102]
  • Damage Modifiers: Surge (sur), +20% [B105, P102]
  • Delay, Variable [B105, P102]
  • Drifting, +20% [B105]
  • Erosive, +10% [P108]
  • Extended Duration, Variable [B105, P102]
    Either level of Permanent not only requires GM approval, as with all modifications, but also requires compelling reasoning and justification; otherwise, Permanent is usually forbidden.
  • Follow-Up, Variable [B105, P102]
    As with Innate Attacks, a spell with this modifier requires an additional spell (cast just after) to be used as the “carrier” spell.
  • Force Field, +20% [P108]
  • Guided or Homing, Variable [B105, P103]
  • Increased 1/2D Range, +5%/level [B106, P103]
  • Increased Max Range, +5%/level [B106, P103]
  • Increased Range, +10%/level [B106, P103]
  • Jet, +0% [B106, P103]
  • Link, +10% [B106, P103]
    Used to create a spell that incorporates two spells into one – note that base costs are added, as are casting times, but durations (where appropriate) must first match, at which point the final spell uses the one duration applicable to each.
  • Long-Range, +50%/level [P108]
  • Low Signature, +10% [B106, P103]
  • Mobile, +40%/level [B107, P104]
  • No Signature, +20% [B106, P103]
  • Overhead, +30% [B107, P104]
  • Persistent, +40% [B107, P104]
  • Ranged, +40% [B107, P105]
  • Rapid Fire, Variable [B108, P105]
  • Reduced Time, +20%/level [B108]
    This can never reduce the casting time of a spell to less than 1 second unless the spell is a Blocking spell, although a spell that gathers strength over time can benefit from levels that would otherwise take the base spell below 1 second.
  • Reliable, +5% per +1 bonus [P109]
  • Respiratory Agent, +50% [B108]
  • Selective Area, +20% [B108, P105]
  • Selective Effect, +20% [P105]
  • Selectivity, +10% [B108, P105]
  • Sense-Based, Variable [B109, P105]
  • Side Effect, Variable [B109, P106]
  • Surprise Attack, +150% [P104]
  • Symptoms, Variable [B109]
  • Underwater, +20% [B109, P107]
  • Variable, +5% [B109, P107]
  • Very Rapid Fire, Variable [P105]
  • Wall, +30% or +60% [B109]


  • Accessibility, Variable [B110, P99]
  • Armor Divisor, Variable [B110, P100]
    Levels are (0.5), (0.1), and (0.1).
  • Backlash, Variable [P104]
  • Blockable, -5% or -10% [P110]
  • Bombardment, Variable [B111, P100]
  • Contact Agent, -30% [B111, P101]
  • Damage Limitations: No Blunt Trauma (nbt), -20% [B111]
  • Damage Limitations: No Knockback (nkb), -10% [B111]
  • Damage Limitations: No Wounding (nw), -50% [B111, P102]
  • Dissipation, -50% [B112]
  • Emanation, -20% [B112, P102]
  • Environmental, Variable [P110]
  • Extra Recoil, -10% per +1 Recoil [B112, P102]
    Can only be applied to a spell that also has the Rapid Fire enhancement but not the Very Rapid Fire enhancement.
  • Inaccurate, -5%/level [B112]
    You may not reduce an attack spell’s Acc below 0.
  • Increased Cost, -50%/level []
    See explanation on the Changes to Magic page.
  • Insubstantial Only, -30% [P111]
  • Melee Attack, Variable [B112, P103]
  • Minimum Range, -5% or -10% [P111]
  • Nuisance Effect, Variable [B112, P104]
  • Onset, Variable [B113, P104]
  • Preparation Required, Variable [B114]
  • Reduced Range, -10%/level [B115, P105]
  • Requires Material Component, -5%/Level [TomM]
    See explanation on the Changes to Magic page. Level is based on the value of the component. Max level is 10.
  • Requires Somatic Component, -10%/Level [TomM]
    Max level is 3.
  • Requires Verbal Component, -10%/Level [TomM]
    See explanation on the Changes to Magic page. All levels require the caster to be able to converse freely and succeed at an enunciation roll. Max level is 5.
  • Resistible, Variable [B115, P105]
    See explanation on the Changes to Magic page. This limitation is only available for spells that affect others in hostile ways and do not already provide resistance rolls. Can include attack spells.
  • Sense-Based, Variable [B115, P105]
  • Short-Range, -10%/level [P112]
  • Specific, Variable [P112]
  • Takes Extra Time, -10%/level [B115, P106]
  • Terminal Condition, Variable [P112]
  • Trigger, Variable [B115, P106]
    This is the modifier used to represent material components being used in the spell. It is assumed that the component is consumed in the casting of the spell.
  • Unreliable, -5% per -1 bonus [P109]
    This does not work like the books indicate, this is simply the limitation version of Reliable, P109.
  • Visible, -10% or -20% [P112]

Modifying Spells

GURPS High Fantasy Belrathius