A tier is the difficulty level of a run. Higher tiers scale enemies faster and pay a larger coin multiplier, and from tier 14 they add fixed battle conditions that switch off the easy ways to kill things. This page lists the coin bonus and unlock wave for all 24 tiers, breaks the tier 14 to 24 battle conditions into readable tables, and explains Overheat.
Updated
- Tiers
- 24 battle conditions from tier 14
- Top coin bonus
- x103 tier 24, vs x1.0 on tier 1
- Unlock wave
- 100 / 300 wave 300 for tier 16 and up
- Overheat
- Wave 15,000 tier 1, earlier on higher tiers
How tiers work
You pick a tier before every run. Each tier has its own enemy scaling, its own coin multiplier, and its own track of milestones. There are 24 tiers. Moving up is a trade: enemies get stronger faster, so you die at a lower wave, but every coin you earn is multiplied by a bigger number.
That trade is why the best farming tier is rarely your highest unlocked one. Non-basic enemies and elites only show up in volume at higher waves, so a tier where you survive deep into the run can out-earn a higher tier where you die early. The coin bonus tells you how much further you would need to fall short before the lower tier wins.
Unlocking tiers still matters even if you never farm them. The coin rewards from daily missions scale with your highest unlocked tier, and each new tier opens a fresh milestone track with gems, Power Stones, labs, and cards.
Coin bonus and unlock wave for every tier
Tiers 2 through 15 unlock at wave 100 of the tier below. From tier 16 on you need wave 300 of the tier below, which means tier 15 is the first tier where a short push to wave 100 is not enough.
| Tier | Coin bonus | Step up | Unlocked by reaching | Overheat wave |
|---|---|---|---|---|
| Tier 1 | x1.0 | - | Available from the start | 15,000 |
| Tier 2 | x1.8 | +80% | Tier 1, wave 100 | 14,750 |
| Tier 3 | x2.6 | +44% | Tier 2, wave 100 | 14,500 |
| Tier 4 | x3.4 | +31% | Tier 3, wave 100 | 14,250 |
| Tier 5 | x4.2 | +24% | Tier 4, wave 100 | 14,000 |
| Tier 6 | x5.0 | +19% | Tier 5, wave 100 | 13,750 |
| Tier 7 | x5.8 | +16% | Tier 6, wave 100 | 13,500 |
| Tier 8 | x6.6 | +14% | Tier 7, wave 100 | 13,250 |
| Tier 9 | x7.5 | +14% | Tier 8, wave 100 | 13,000 |
| Tier 10 | x8.7 | +16% | Tier 9, wave 100 | 12,750 |
| Tier 11 | x10.3 | +18% | Tier 10, wave 100 | 12,500 |
| Tier 12 | x12.2 | +18% | Tier 11, wave 100 | 12,250 |
| Tier 13 | x14.7 | +20% | Tier 12, wave 100 | 12,000 |
| Tier 14 | x17.6 | +20% | Tier 13, wave 100 | 11,750 |
| Tier 15 | x21.3 | +21% | Tier 14, wave 100 | 11,500 |
| Tier 16 | x25.2 | +18% | Tier 15, wave 300 | 11,250 |
| Tier 17 | x29.1 | +15% | Tier 16, wave 300 | 11,000 |
| Tier 18 | x33.0 | +13% | Tier 17, wave 300 | 10,750 |
| Tier 19 | x40.0 | +21% | Tier 18, wave 300 | 10,500 |
| Tier 20 | x48.0 | +20% | Tier 19, wave 300 | 10,250 |
| Tier 21 | x60.0 | +25% | Tier 20, wave 300 | 10,000 |
| Tier 22 | x72.0 | +20% | Tier 21, wave 300 | 10,000 |
| Tier 23 | x86.0 | +19% | Tier 22, wave 300 | 10,000 |
| Tier 24 | x103.0 | +20% | Tier 23, wave 300 | 10,000 |
Step up is the coin bonus increase over the previous tier. The tier 22 unlock follows the rule stated on the wiki Tiers page; the tier 21 milestone table on the wiki does not show the unlock row.
The coin bonus grows by a flat 0.8 per tier up to tier 8, then the steps get larger. The biggest relative jumps late on are tier 19 (+21% over tier 18) and tier 21 (+25% over tier 20). Tier 24 pays 103 times what tier 1 does for the same kill.
Milestones and what tiers unlock
Every tier has 23 milestone waves: every 10 waves up to 100, then 150, 200, 250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 2,000, 2,500, and 4,500. Reaching a wave on a tier lets you claim that tier's reward for it. There are two columns of rewards, a free standard track and a paid premium track.
Standard rewards are where the game hides its feature unlocks. Labs, tournaments, perks, guilds, cards, and most individual lab research are all tied to a specific tier and wave. A few examples from the early tiers:
- Tier 1: Labs at wave 30, Tournaments at wave 60, Events at wave 70.
- Tier 2: Perks at wave 150.
- Tier 3: Guilds at wave 10.
- Tier 9: the first enemy labs at waves 10 and 20.
- Tier 16: Card Mastery at wave 100.
- Tier 19: elite enemy health and attack labs at wave 60.
The last milestone on every tier is wave 4,500. On tiers 1 to 12 the standard reward there is a relic. From tier 13 it is a permanent bonus, usually +10% to one stat. Clearing wave 4,500 is also what makes the Overheat button appear for that tier.
| Tier | Standard reward | Premium reward |
|---|---|---|
| Tier 1 | Relic: Coins +2% | 15 Stones |
| Tier 2 | Relic: Lab Speed +1.5% | 20 Stones |
| Tier 3 | Relic: Critical Factor +2% | 20 Stones |
| Tier 4 | Relic: Damage +2% | 25 Stones |
| Tier 5 | Relic: Health +1.5% | 25 Stones |
| Tier 6 | Relic: Defense Absolute +2% | 25 Stones |
| Tier 7 | Relic: Coins +5% | 25 Stones |
| Tier 8 | Relic: Damage / Meter +5% | 30 Stones |
| Tier 9 | Relic: Health +5% | 30 Stones |
| Tier 10 | Relic: Damage / Meter +5% | 30 Stones |
| Tier 11 | Relic: Defense Absolute +10% | 35 Stones |
| Tier 12 | Relic: Lab Speed +10% | 40 Stones |
| Tier 13 | Coins +10% | 45 Stones |
| Tier 14 | Tower Damage +10% | 60 Stones |
| Tier 15 | Critical Factor +10% | 100 Stones |
| Tier 16 | Tower Health +10% | 60 Stones |
| Tier 17 | Damage / Meter +10% | 100 Stones |
| Tier 18 | Lab Speed +10% | 130 Stones |
| Tier 19 | Tower Damage +10% | 60 Stones |
| Tier 20 | Ultimate Damage +8% | 100 Stones |
| Tier 21 | Lab Speed +10% | 130 Stones |
| Tier 22 | Lab Speed +10% | 60 Stones |
| Tier 23 | Coin Bonus +10% | 100 Stones |
| Tier 24 | Tower Damage +10% | 130 Stones |
The full searchable list of every reward is on the Milestones reference.
Tier battle conditions (tier 14 and up)
Tiers 1 to 13 have no battle conditions. From tier 14 each tier applies a fixed set, and unlike tournament conditions they never rotate. Each tier keeps everything from the tier below, makes it stronger, and usually adds one or more new conditions. By tier 24 all 19 are active.
| Tier | Active | New on this tier | Reaches max level (L95) |
|---|---|---|---|
| Tier 14 | 6 | More Bosses, Orb Resistance, Death Ray Resistance, Thorns Resistance, Plasma Cannon Resistance, Skip Reduction - Subtract | - |
| Tier 15 | 8 | Knockback Resistance, Armored Enemies | - |
| Tier 16 | 9 | Protector's Ultimate | - |
| Tier 17 | 10 | Tank's Ultimate | - |
| Tier 18 | 13 | Ray's Ultimate, Scatter's Ultimate, Vampire's Ultimate | - |
| Tier 19 | 14 | Fast's Ultimate | Orb Resistance, Death Ray Resistance |
| Tier 20 | 15 | Boss's Ultimate | - |
| Tier 21 | 16 | Mass Enforcement | Knockback Resistance, Protector's Ultimate |
| Tier 22 | 17 | Saboteur's Ultimate | Thorns Resistance, Plasma Cannon Resistance, Tank's Ultimate |
| Tier 23 | 18 | Commander's Ultimate | Ray's Ultimate, Scatter's Ultimate, Vampire's Ultimate |
| Tier 24 | 19 | Overcharge's Ultimate | Armored Enemies, Fast's Ultimate |
The tables below split the conditions by what they attack. A dash means the condition is not active on that tier. You can also browse the same data on the battle conditions table.
Resistances
These cut down the tools that carry the lower tiers. The value is how much of the normal effect is left. Orbs and Death Ray stop killing outright and instead deal that percentage of enemy health. Thorns and Plasma Cannon deal that share of their usual damage. Knockback keeps that share of its force.
| Tier | Orbs | Death Ray | Thorns | Plasma Cannon | Knockback |
|---|---|---|---|---|---|
| Tier 14 | 50% | 50% | 80% | 80% | - |
| Tier 15 | 40% | 40% | 70% | 70% | 60% |
| Tier 16 | 30% | 30% | 60% | 60% | 50% |
| Tier 17 | 20% | 20% | 50% | 50% | 40% |
| Tier 18 | 10% | 10% | 40% | 40% | 30% |
| Tier 19 | 5% | 5% | 30% | 30% | 20% |
| Tier 20 | 5% | 5% | 20% | 20% | 10% |
| Tier 21 | 5% | 5% | 10% | 10% | 5% |
| Tier 22 | 5% | 5% | 5% | 5% | 5% |
| Tier 23 | 5% | 5% | 5% | 5% | 5% |
| Tier 24 | 5% | 5% | 5% | 5% | 5% |
Tier 14 is the gentle version: orbs and Death Ray take half an enemy's health per hit and thorns still does 80%. By tier 19 orbs and Death Ray are at 5%, and by tier 22 every resistance is at 5%. Builds that lean on thorns and Plasma Cannon to delete bosses lose that option step by step from tier 14 to tier 22.
Wave pressure
| Tier | Boss wave | Level skip chance | Armored Enemies | Mass gain per wave alive |
|---|---|---|---|---|
| Tier 14 | Every 9 waves | -2.5% | - | - |
| Tier 15 | Every 8 waves | -5% | 10 hits | - |
| Tier 16 | Every 7 waves | -7.5% | 20 hits | - |
| Tier 17 | Every 6 waves | -10% | 30 hits | - |
| Tier 18 | Every 5 waves | -12.5% | 40 hits | - |
| Tier 19 | Every 5 waves | -20% | 50 hits | - |
| Tier 20 | Every 5 waves | -27.5% | 60 hits | - |
| Tier 21 | Every 5 waves | -35% | 70 hits | 50% |
| Tier 22 | Every 5 waves | -37.5% | 80 hits | 70% |
| Tier 23 | Every 5 waves | -40% | 90 hits | 100% |
| Tier 24 | Every 5 waves | -42.5% | 95 hits | 130% |
Skip reduction is subtracted from your Enemy Attack and Health Level Skip chances. Armored enemies ignore that many hits before taking damage. Without Mass Enforcement, enemies gain 4% mass per wave alive.
More Bosses shortens the boss cycle from every 10 waves to every 9 on tier 14, and down to every 5 from tier 18. On tier 14 that means 11 bosses on the way to wave 100 instead of 10, with the last one at wave 99. Skip Reduction eats directly into enemy level skips, reaching 42.5 percentage points on tier 24. Mass Enforcement arrives on tier 21 and makes long-lived enemies much harder to knock back.
Normal enemy and boss ultimates
Ultimates give an enemy type a new ability. Protector and Tank ultimates run on a timer, shown as active time out of a 300 second cycle. At 285s out of 300s they are on almost permanently.
| Tier | Protector's | Tank's | Fast's | Boss's overheal |
|---|---|---|---|---|
| Tier 16 | 60s / 300s | - | - | - |
| Tier 17 | 105s / 300s | 60s / 300s | - | - |
| Tier 18 | 150s / 300s | 105s / 300s | - | - |
| Tier 19 | 195s / 300s | 150s / 300s | 2 enemies | - |
| Tier 20 | 240s / 300s | 195s / 300s | 4 enemies | +20% |
| Tier 21 | 285s / 300s | 240s / 300s | 5 enemies | +35% |
| Tier 22 | 285s / 300s | 285s / 300s | 7 enemies | +50% |
| Tier 23 | 285s / 300s | 285s / 300s | 8 enemies | +65% |
| Tier 24 | 285s / 300s | 285s / 300s | 10 enemies | +80% |
- Protector's Ultimate: shielded enemies also become immune to knockback, Shockwave, and Black Hole damage.
- Tank's Ultimate: Tanks behave like bosses but stop moving once they are inside tower range.
- Fast's Ultimate: each Fast enemy speeds up a number of nearby enemies to match its own speed.
- Boss's Ultimate: bosses spawn with extra health on top of their maximum.
Elite ultimates
| Tier | Ray fire rate | Scatter child health | Vampire drain speed |
|---|---|---|---|
| Tier 18 | +40% | +40% | +40% |
| Tier 19 | +70% | +70% | +70% |
| Tier 20 | +100% | +100% | +100% |
| Tier 21 | +130% | +130% | +130% |
| Tier 22 | +160% | +160% | +160% |
| Tier 23 | +190% | +190% | +190% |
| Tier 24 | +190% | +190% | +190% |
All three start on tier 18 and scale together. At tier 23 and 24 Rays fire 190% faster, Scatter children have 190% more health, and Vampires drain 190% faster. See the Enemies guide for the base behavior these modify.
Fleet ultimates
| Tier | Saboteur's | Commander's | Overcharge's |
|---|---|---|---|
| Tier 22 | 10% | - | - |
| Tier 23 | 17.5% | 60s / 300s | - |
| Tier 24 | 25% | 105s / 300s | +0.1 |
- Saboteur's Ultimate: the Saboteur gets a chance to attack through the Wall, which is otherwise a complete block against it.
- Commander's Ultimate: a pulse that lands inside tower range lowers the tower's attack and health by 1 for the rest of the run. The table lists it as active time out of a 300 second cycle.
- Overcharge's Ultimate: adds to the damage scaling of each returning projectile hit.
Overheat
Overheat was added in v28 to stop runs from going on forever. Once you have cleared wave 4,500 on a tier, an Overheat button appears on the battle screen showing when the extra conditions start and what they are. It does not end your run. It makes the run steadily harder from that wave.
- Tier 1 start
- Wave 15,000
- Per tier
- 250 waves earlier
- Tier 21 to 24 start
- Wave 10,000
- Skip Decay
- 1% per wave
Two conditions switch on at the Overheat wave on every tier. Skip Decay lowers your enemy attack and health level skip chances by 1% each wave. More Fleets adds a fleet every 100 waves, which is how fleet enemies end up on tiers below 14. The start wave for each tier is in the tier table above.
What changes when you push a new tier
Up to tier 13 the job is always the same: reach wave 100 once. Burst tools such as Second Wind, Demon Mode, Nuke, and Energy Shield can carry a tower past boss waves it could not beat in a normal run, and that works because the target is so short.
Tier 14 keeps the wave 100 target but adds the first battle conditions. Plasma Cannon and thorns drop to 80% damage, orbs and Death Ray stop being instant kills, and there is one more boss to get through. Tier 15 is the real wall. The conditions get stronger, Knockback Resistance and Armored Enemies arrive, and the target for the next unlock triples to wave 300.
| To unlock | Reach | Conditions on that tier |
|---|---|---|
| Tiers 2 to 14 | Wave 100 on tiers 1 to 13 | None |
| Tier 15 | Wave 100 on tier 14 | 6 conditions, boss every 9 waves |
| Tier 16 | Wave 300 on tier 15 | 8 conditions, boss every 8 waves |
| Tiers 17 to 24 | Wave 300 on tiers 16 to 23 | 9 to 18 conditions |
Frequently asked questions
How do you unlock the next tier in The Tower?
Reach wave 100 on your current tier to unlock the next one, up to tier 15. Tier 16 and every tier after it needs wave 300 on the tier below. The unlock is a milestone reward you claim from the Milestones button.
What is the coin bonus for each tier?
It starts at x1.0 on tier 1 and rises by 0.8 per tier to x6.6 on tier 8. After that the steps grow: x8.7 on tier 10, x21.3 on tier 15, x48 on tier 20, and x103 on tier 24.
Which tiers have battle conditions?
Tiers 14 to 24. Tier 14 has 6 fixed conditions, including boss waves every 9 waves and orbs dealing 50% of enemy health instead of killing. Each tier adds more, and tier 24 has all 19.
What is Overheat and when does it start?
Overheat adds Skip Decay (1% per wave) and a fleet every 100 waves late in a run. It starts at wave 15,000 on tier 1 and 250 waves earlier per tier, down to wave 10,000 on tiers 21 to 24. The panel appears once you have cleared wave 4,500 on that tier.
How many tiers are there in The Tower?
There are 24 tiers. Tiers 1 to 13 have no battle conditions, tiers 14 to 24 have fixed ones that get stronger with each tier.
Is the highest tier always best for farming coins?
No. A higher tier multiplies coins per kill, but you also die at a lower wave, before elites and high-value enemies spawn in volume. Compare coins per hour on two tiers rather than assuming the higher one wins.
Sources and credits
The numbers on this page come from the community-maintained The Tower - Idle Tower Defense Wiki and were reorganized and rewritten for Towerstats.org. Wiki text is available under CC BY-SA.