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How to Track Concentration in D&D 5e Without Slowing the Table
Learn how to track concentration in D&D 5e: save DCs, temp HP, spell slots and simple table systems so no spell drops by accident or lingers by mistake.
The simplest way to track concentration is to give every concentrating creature one visible marker, then check that marker each time the creature takes damage, becomes incapacitated or casts another concentration spell. Everything else is arithmetic: a Constitution saving throw against a DC of 10 or half the damage, whichever is higher. This guide covers the rules, the math, the table systems that work and how temporary hit points, spell slots and hit points fit in.
TL;DR
Only one concentration spell at a time. Casting a second one ends the first.
Each time you take damage, make a Constitution save at DC 10 or half the damage, whichever is higher. Multiple hits mean multiple saves.
Temporary hit points soak up damage but do not lower the save DC, because the full hit still counts.
Put one marker on the concentrating creature's initiative slot, and remove it the moment the spell ends.
Track hit points, temp HP and spell slots in the same place, on paper or in a browser tool, so concentration checks never wait on a hunt for numbers.
Table of Contents
What concentration does and when it ends
The concentration check: DC math you can do in your head
A table system that tracks concentration without slowing play
Temporary hit points and concentration
Tracking hit points and spell slots alongside it
Moving it into a browser: what digital tracking should do
Our perspective
Try it in a session
Common concentration situations, settled
FAQ
Sources
What concentration does and when it ends
Concentration is the rule that keeps casters from stacking buffs and ongoing effects. According to the SRD 5.1 rules text.pdf/102), you can't concentrate on two spells at once. If you cast another spell that requires concentration, the first one ends immediately.
The same page lists what else breaks it:
Taking damage. You make a Constitution saving throw to hold on.
Becoming incapacitated or dying. No save is offered. The effect simply ends.
Environmental phenomena. The GM may call for a DC 10 Constitution save for things like a wave crashing over a storm-tossed ship.
Ordinary activity such as moving and attacking does not interfere with concentration. The spell's own description tells you if it needs concentration, so the first job at the table is simply noticing when a spell has that tag and saying so out loud.
A few related limits come up constantly. As DnD Lounge explains, you have a single "concentration slot". That means you can't concentrate on a class feature and a spell at the same time, and you can't ready a spell while concentrating on another one.
The concentration check: DC math you can do in your head
Whenever you take damage while concentrating, the SRD says to make a Constitution saving throw. The DC is 10 or half the damage you take, whichever is higher (SRD 5.1.pdf/102)). The 2024 rules keep the same formula, round half the damage down and cap the DC at 30, according to Roll for Two. That same article notes the incapacitated condition now spells out in its own text that it ends concentration.
The practical consequence: any hit of 20 damage or less is DC 10. DnD Lounge notes that 21 damage is still DC 10, while 22 damage pushes it to DC 11. You only start doing real math on big hits.
| Damage taken | Half the damage (rounded down) | Save DC |
| 4 | 2 | 10 |
| 14 | 7 | 10 |
| 20 | 10 | 10 |
| 22 | 11 | 11 |
| 24 | 12 | 12 |
| 40 | 20 | 20 |
Every hit is its own save
If a creature is hit more than once in a turn, each instance of damage calls for a separate check. Arcane Eye makes the same point: multiple hits mean multiple checks. This is why a monster with three small attacks is often more dangerous to a concentrating wizard than a single big one. Three hits of 5 damage mean three DC 10 saves, not one.
A good habit for the GM: announce the damage per attack, not as a combined total, and ask the player to roll as each lands. Players learn quickly to say "concentrating" before you even ask.
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