Armor thresholds

HE penetration

Here are some common armor thicknesses and the minimum HE shell diameters needed to penetrate them, according to the HE penetration formula.

1/6, 1/5 and 1/4 are the HE shells' penetration coefficients.

Armor thickness (mm)	Occurrences (non-exhaustive)	HE shell diameter needed to penetrate (mm)
		1/6	1/6 with IFHE	1/5	1/5 with IFHE	1/4	1/4 with IFHE
013	Low-tier destroyer plating	075	063	062.5	052.5	050	042
016	Tier 3 battleship bow/stern Tier 6 - 7 battleship superstructure Most tier 6 - 7 cruiser bow/stern The entirety of British light cruiser and Smolensk hull plating Tier 6 - 7 destroyer plating	093	075	077.5	062.5	062	050
019	Tier 4 - 5 battleship bow/stern Tier 6 - 7 light cruiser side plating Tier 8 - 10 battleship superstructure Tier 8 - 10 destroyer plating	111	093	092.5	077.5	074	062
020	Tier 6 and 7 cruisers' decks Most tier 8 - 10 cruisers' bow/stern Tier 8 - 10 light cruisers' side plating	117	093	097.5	077.5	078	062
025	Tier 6 and 7 cruisers' decks Most tier 8 - 10 cruisers' bow/stern Tier 8 - 10 light cruisers' side plating Audacious bow/stern	147	117	122.5	097.5	098	078
026	Tier 6 and 7 battleship bow/stern and some of their casemate plating	153	123	127.5	102.5	102	082
027	Tier 8 and 9 cruiser decks Some tier 8 - 10 cruiser bow/stern (USN and German heavy cruisers)	159	129	132.5	107.5	106	086
30	Most tier 10 cruiser deck plating, most tier 10 heavy cruiser side plating Ägir, Siegfried, Albemarle and Drake deck plating	177	141	147.5	117.5	118	094
032	Tier 8 - 10 battleship bow/stern Tier 8 - 10 British and French battleships' casemate plating Slava deck plating	189	153	157.5	127.5	126	102
038	Tier 8 - 10 USN battleship decks	225	183	187.5	152.5	150	122
040	Petropavlovsk, Vladivostok casemate plating	237	189	197.5	157.5	158	126
050	Khabarovsk, Delny, Zorkiy belt Moskva, Stalingrad, casemate plating Tier 7 - 11 German battleships' decks , Cristoforo Colombo deck armor Petropavlovsk Front end armor belt Admiral Nakhimov, Manfred von Richthofen Flight deck armor	297	237	247.5	197.5	198	158
051	Vermont deck and aux armor	303	243	252.5	202.5	202	162
060	Sovetsky Soyuz, AL Sov. Rossiya and Kremlin deck	357	285	297.5	237.5	238	190
114	Audacious citadel armor (Currently only Thunderer and Hannover can penetrate)	684	547	570.0	456.0	456	366

HE penetration (before Update 0.9.2)

OLD INFORMATION AS PER UPDATE 0.9.2. NEW INFORMATION IS UNDER CONSTRUCTION. THE UPDATE IS QUITE COMPLEX, SOME TIME IS NEEDED TO PROCESS ALL CHANGES.

Here are some common armor thicknesses and the minimum HE shell diameters needed to penetrate them, according to the HE penetration formula. "Super" refers to the 1/4 HE penetration coefficient.

By armor thickness

Armor thickness	Occurrences (non-exhaustive)	Beneficiaries (without IFHE) (non-exhaustive)	Beneficiaries (with IFHE) (non-exhaustive)
16 mm	Tier 3 battleship bow/stern Tier 6 - 7 battleship superstructure Most tier 6 - 7 cruiser bow/stern The entirety of British light cruiser and Smolensk hull plating Tier 6 - 7 destroyer plating	All guns of 114 mm or more calibre
19 mm	Tier 4 - 5 battleship bow/stern Tier 6 - 7 light cruiser side plating Tier 8 - 10 battleship superstructure Tier 8 - 10 destroyer plating	All guns of 114 mm or more calibre
25 mm	Tier 6 and 7 cruisers' decks, most tier 8 - 10 cruisers' bow/stern, tier 8 - 10 light cruisers' side plating	Heavy cruisers (203mm) Light cruisers (155mm) Japanese 100 mm guns German 105 mm secondary guns	Most destroyers (120 mm - 150 mm)
26 mm	Tier 6 and 7 battleship bow/stern and some of their casemate plating	Heavy cruisers (203 mm) Light cruisers (180 mm, T8+ 152/155 mm) Japanese 100 mm guns German 105 - 150 mm guns	Light cruisers (152mm) up to and including tier 7 Most destroyers (127 mm - 139 mm)
27 mm	Tier 8 and 9 cruiser decks, some tier 8 - 10 cruiser bow/stern (USN and German heavy cruisers)	Heavy cruisers (203 mm) Light cruisers (180 mm, T8+ 152/155 mm) Japanese 100 mm guns German 128 - 150 mm guns	Light cruisers (152mm) up to and including tier 7 Some destroyers (130 mm - 139 mm, 100 mm super)
30 mm	Most tier 10 cruiser deck plating, most tier 10 heavy cruiser side plating, Ägir, Siegfried, Albemarle and Drake deck plating	Heavy cruisers (203 mm) Light cruisers (180 mm, T8+ 152/155 mm) Japanese 100 mm guns German 128 - 150 mm guns	Tier 7 and lower light cruisers (152 mm, 155 mm)
32 mm	Tier 8 - 10 battleship bow/stern, tier 8 - 10 British and French battleships' casemate plating, Slava deck plating	Heavy cruisers (203 mm) German 128 - 150 mm guns (both main and secondary)	Most light cruisers (152 mm, 155 mm, 180 mm) Japanese 100 mm guns
38 mm	Tier 8 - 10 USN battleship decks	Henri IV (240 mm) Goliath (234 mm) Superheavy cruisers (305 - 310 mm) All german cruisers German 150 mm guns	All non-German 203 mm ships, and Mogami. Not worth it on 203mm guns, since you lose a lot fire chance just to penetrate this category of armor.
50 mm	Khabarovsk belt Moskva, Stalingrad and Petropavlovsk casemate plating Tier 7 - 10 German battleships' decks	German 203 mm (Hindenburg, Roon, Hipper, Yorck) Superheavy cruisers (305 - 310 mm)	Henri IV (240 mm) (not worth it, considering how much fire chance you lose)
60 mm	Sovetsky Soyuz, AL Sov. Rossiya and Kremlin deck	Only battleship calibre HE can penetrate their deck armor	German 203 mm (Hindenburg, Roon, Hipper, Yorck) Superheavy cruisers (305 - 310 mm), but it's not worth speccing into IFHE considering how much fire chance you lose

By HE diameter

HE shell	Occurrences (non-exhaustive)	Maximum armor thickness penetrated		IFHE beneficial against (non-exhaustive)
		Without IFHE	With IFHE
Tier 8 - 10 152 mm 180 mm Japanese 100 mm	Most light cruisers Some Japanese destroyers/secondaries	30 mm	32 mm	Tier 8 - 10 battleship bow/stern, tier 8 - 10 British and French battleships' casemate plating, Slava deck plating
419-420 mm with improved HE penetration	Conqueror, Friedrich der Große, Großer Kurfürst, Lion	104 mm	136 mm	Citadels: Cleveland, Edinburgh, Fiji, Helena, New Orleans, Worcester
456 mm with improved HE penetration	Thunderer	114 mm	142 mm	Citadels: Cleveland, Edinburgh, Fiji, Helena, New Orleans, Worcester, Audacious

Notes

• As per the tables above, 152 mm and 155 mm HE, primarily found on light cruisers; and 100 mm HE, found on Japanese gunboat destroyers and some secondary batteries, are by far the biggest beneficiaries.
• 180 mm HE benefits less from IFHE because of a more drastic relative reduction in fire chance for not much gain in both absolute and impactful damage output
• The only secondary weapons that may benefit from IFHE are German 105 mm secondaries with 26 mm base penetration, however, they give up a lot of fire chance for the ability to penetrate up to and including 32 mm plating, which is most of the time not worth it
• Some other ships gain some benefit, but this is not generally considered worth the cost in skill points and the tradeoff in fire starting capabilities.

AP overmatch

An AP shell whose diameter is greater than 14.3 times the thickness of an armor plate will overmatch and pass through it regardless of angle. Here are some thresholds where this occurs, which determines whether it is feasible to "bow-tank" a particular AP shell.

Armor thickness	AP shell diameter needed to overmatch	Occurrences (non-exhaustive)	Notes
10 mm	144 mm	Tier 4-5 cruiser superstructure Tier 4-5 destroyer plating	Will bounce most destroyer (except German 150mm guns) shells if sufficiently angled, but not most light cruiser shells.
13 mm	186 mm	Tier 4 - 5 battleship superstructure Tier 4 and 5 cruiser bow/stern Most tier 6 - 7 cruiser superstructure Tier 8 - 10 and Super destroyer superstructure plating	Will bounce light cruiser shells if sufficiently angled but not heavy cruiser shells (203 mm and larger).
16 mm	229 mm	Tier 3 battleship bow/stern Tier 6 - 7 battleship superstructure Most tier 6 - 7 cruiser bow/stern The entirety of British light cruiser and Smolensk hull plating Tier 6 - 7 destroyer plating	Will bounce almost all cruiser shells if sufficiently angled. Notable: Can bounce Moskva (220 mm) but not Goliath (234 mm), Henri IV (240 mm), Graf Spee, Scharnhorst or Gouden Leeuw (283 mm).
19 mm	272 mm	Tier 4 - 5 battleship bow/stern Tier 6 - 7 light cruiser side plating Tier 8 - 10 and Super battleship and cruiser superstructure Tier 8 - 10 and Super destroyer plating Tier 8, 10 and Super aircraft carrier bow/stern plating	Will bounce up to 254 mm AP if sufficiently angled. Notable: Can bounce Henri IV (240 mm), but not Graf Spee, Scharnhorst, Gouden Leeuw (283 mm) and other battlecruiser AP shells (305 - 330 mm).
25 mm	358 mm	Tier 6 and 7 cruisers' decks; the bow/stern plating of Yorck, Pensacola, New Orleans and Florida; most tier 8 - 10 and Super cruisers' bow/stern plating, tier 8 - 10 light cruisers' side plating; bow/stern plating of Mackensen, Prinz Heinrich, Borodino, Constellation, Slava and Incomparable	Will bounce up to 14-inch shells (356 mm) if sufficiently angled.
26 mm	372 mm	Tier 6 and 7 battleship bow/stern and some of their casemate plating	Will bounce up to 14-inch shells (356 mm) if sufficiently angled.
27 mm	387 mm	Tier 8 and 9 cruiser decks, some tier 8 - 10 cruiser bow/stern (USN and German heavy cruisers); parts of Zieten, Prinz Rupprecht and Schlieffen bow/stern plating.	Will bounce up to 15-inch shells (381 mm) if sufficiently angled.
30 mm	430 mm	Most tier 10 and Super cruiser deck plating, most tier 10 and Super heavy cruiser side plating, Ägir, Siegfried, Albemarle, Cheshire, Drake, Haarlem and Johan de Witt deck plating.	At the moment, République (431 mm), Thunderer (457 mm), Georgia (457 mm), Vermont (457 mm), Ohio (457 mm), Kremlin (457 mm), Preussen (457 mm), Adatara (457 mm), Bungo (457 mm), Tsurugi (457 mm), Ruggiero di Lauria (457 mm), Sun Yat-Sen (457 mm), Musashi (460 mm), Yamato (460 mm), super battleship Hannover (483 mm), Incomparable (508 mm), super battleship Satsuma and Shikishima (both 510 mm) can overmatch.
32 mm	458 mm	Tier 8-10 and Super battleship bow/stern, tier 8 - 10 and Super British and French battleships' casemate plating, Slava deck plating	At the moment, Musashi, Yamato (both 460 mm), Hannover (483 mm), Incomparable (508 mm), Satsuma and Shikishima (both 510 mm) can overmatch.
35 mm	500 mm	Tier 9 Riga deck plating, tier 6 Fuso deck plating	At the moment, Incomparable (508 mm), Satsuma and Shikishima (both 510 mm) can overmatch.

Notes

• Changes to the Inertia Fuse for HE Shells Skill (Update 0.9.2).

• The formula for fire chance can be found in Fires.

• IFHE All Night Long by LittleWhiteMouse.