Magic layers: calculating power and toughness
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Calculate a Magic creature's power and toughness by applying the relevant effects in layer 7's order: characteristic-defining abilities, effects setting values, modifications and counters, then switches. You do not simply apply every change in the order the cards arrived. Earlier layers may also change the creature's types or remove an Ability before this calculation.
For most everyday disagreements, identifying whether an effect sets, modifies or switches a value resolves the problem. Use that classification first, then consider timestamps and dependencies within the appropriate layer rather than reaching immediately for the most complicated part of the rules.
Separate the printed numbers from current values
The numbers printed in a creature's lower-right corner are a starting point, not necessarily its current power and toughness. Continuous effects, counters and characteristic-defining abilities can change the result. A creature represented by a card printed as 2/2 can legally be 5/4 without any change to the cardboard.
Write down the current effects in plain language. “Base becomes 1/1,” “gets +3/+0” and “has two +1/+1 counters” describe different operations. Classifying them before doing arithmetic prevents a familiar mistake: treating a base-setting effect as though it erases every later modification and counter.
Also keep damage separate. Two damage marked on a 4/4 does not make it a 4/2. The creature still has four toughness, with two damage marked. Its destruction through lethal damage is checked against that toughness; damage is not a layer-7 modifier to subtract from the displayed statistic.
The four relevant sublayers
The current rules organise layer 7 into four sublayers. Older guides may split counters into a separate sublayer, so use a current rules source rather than relying on an old diagram. The practical current grouping puts ordinary modifications and relevant counters together in 7c.
| Sublayer | Operation | Typical description |
|---|---|---|
| 7a | Characteristic-defining ability | A qualifying ability defines a starred value |
| 7b | Set power or toughness | Base power and toughness become specific values |
| 7c | Modify without setting | Get +2/+2, get -1/-1, or apply counters |
| 7d | Switch | Exchange the resulting power and toughness |
This order is a procedure for evaluating continuous effects, not a stack of abilities waiting to resolve. Players do not receive a new response window between applying 7b and 7c. First resolve the spell or ability creating an effect where appropriate; then calculate the resulting characteristics using the layer system.
Setting a base value does not erase counters
Imagine a creature printed as 4/4, carrying two +1/+1 counters and affected by a spell that gives it +3/+0 until end of turn. Another effect makes its base power and toughness 1/1. With no additional relevant effects, calculate the set value first, then the counters and temporary modification.
The result is 6/3: start with 1/1, add the two counters to reach 3/3, then add +3/+0. The ordering of the two ordinary additions does not change this simple arithmetic. The important order is that the base-setting operation occurs before the modifications.
If the temporary +3/+0 ends, the creature becomes 3/3 while the counters and base-setting effect remain. If the base-setting effect later ends too, return to the appropriate underlying value and reapply the remaining modifications. Layers are recalculated from the current effects; the creature does not permanently remember an intermediate 1/1 as its new printed statistics.
Switching happens after ordinary modifications
Take a hypothetical 1/4 creature affected by +2/+0 and an effect switching its power and toughness. The modification produces 3/4; the switch then produces 4/3. Reading the switch first and adding two to the resulting power would produce the wrong 6/1 result.
This remains true if the +2/+0 effect was created after the switching effect. Different sublayers determine the order before timestamps come into play. “My pump spell resolved most recently” does not move it after a switch that belongs in the later sublayer.
Two applicable switching effects can reverse the values twice. Track the actual effects and their durations instead of leaving a single “switched” marker that cannot represent a second switch. When one effect ends, the result can change again without anyone casting another spell.
Characteristic-defining abilities need their own check
Some creatures have a qualifying characteristic-defining ability that determines power or toughness from a changing quantity. A star in the printed value is a clue, but not every text box containing a variable is automatically such an ability. The rules define the category through specific requirements.
For a simplified example, suppose a creature's qualifying ability defines both values as the number of a certain object, and that number is four. Begin with the 4/4 result in 7a. An applicable effect setting base values to 2/2 in 7b then overrides those values for the later calculation.
If the setting effect ends, the characteristic-defining ability continues to use the current counted quantity. If the quantity has become six, you start that later calculation at 6/6, not the earlier four. Do not turn a continuously evaluated definition into a snapshot unless the effect actually instructs a snapshot.
Earlier layers can remove the Ability first
A power-and-toughness question sometimes depends on an effect applied in an earlier layer. Removing Abilities belongs before layer 7. If the relevant defining Ability has been removed, you cannot automatically calculate layer 7 as though that Ability were still functioning.
Similarly, type-changing effects can determine whether an object is a creature at all, and other effects may apply to a particular creature type. Resolve those category questions before multiplying or adding numbers. Arithmetic cannot rescue a calculation based on an Ability the creature does not currently have.
For a complicated interaction, write an effect list rather than quoting only two card names. Include type changes, Ability removal, base-setting instructions, bonuses, counters and switches. This gives a judge the information needed to locate the actual issue instead of asking them to infer the board from a final claimed statistic.
Timestamps apply within the relevant grouping
If two ordinary effects both set base power and toughness in 7b, their timestamps can matter. A hypothetical effect setting 2/2 followed by another setting 5/5 generally leaves the later applicable set values, before applying modifications. Reverse their relevant timestamps and the base result can differ.
That does not mean the newest effect always wins across every layer. A later 7b effect still comes before a 7c bonus and a 7d switch. Always identify the sublayer first. Timestamp is a rule for order within an appropriate group, not permission to reorganise the full evaluation.
Dependencies can change ordinary timestamp order in applicable circumstances. They are a precise rules relationship, not a synonym for “these cards interact.” If an interaction genuinely involves a dependency, consult the rules or a judge with the complete text. Most simple set-plus-counter questions need no dependency analysis.
Check state after calculating the values
Once current toughness is established, state-based actions can matter. A creature with zero or less toughness is put into the graveyard by the relevant state-based action. Indestructible does not prevent that outcome, because it is not destruction caused by lethal damage or an instruction to destroy.
A creature with positive toughness and sufficient marked damage presents a different check. For example, a 3/3 with two damage can survive, but reducing its toughness to two may make that existing damage lethal. A change in toughness can therefore alter survival without dealing any new damage.
Use distinct markers for counters, temporary modifications and damage. A single pile of dice with no explanation makes it difficult to recalculate when an effect expires. A brief note saying “two counters, two damage, +3/+0 this turn” preserves the causes and lets both players verify the result.
Keep the layer calculation separate from the timeline
For practice, list three effects in the order they were created, then assign each to its sublayer in a second column. A base-setting effect created last still precedes ordinary modifications in the calculation. Add a separate column for expiry so that ending one effect removes only its own contribution. This record makes it possible to recompute the creature after a turn ends without guessing which intermediate number was supposed to remain.
Frequently asked questions
Does making a creature 1/1 remove its +1/+1 counters?
An ordinary base-setting effect does not remove counters. Apply the base value in 7b and the counters in 7c. An effect that explicitly removes counters is a separate instruction.
Does marked damage lower toughness?
No. Damage and toughness are different information. Calculate current toughness through the layer system, then use the applicable state-based actions to check damage and other conditions.
Why is my pump spell applied before an older switch?
Ordinary power and toughness modifications are evaluated in 7c, before switches in 7d. The sublayer order applies even when the modification was created later than the switching effect.