Damage Threshold Damage Threshold is a combat statistic in " Fallout " , " Fallout 2 " , " " , and " " . It was removed in " Fallout 3 " , leaving Damage Resistance as the only armor statistic . However , it was restored in " Fallout : New Vegas " , before being removed yet again in " Fallout 4 " . " Fallout " , " Fallout 2 " , " Fallout Tactics " . In the original Fallout games , DT ( Damage Threshold ) is one of three stats by which a character can reduce or avoid damage . The other stats are AC ( Armor Class ) and DR ( Damage Resistance ) . DT occupies the " middle step " for combat and simulates the effect of how tough armor can immediately stop a bullet cold , no matter how many successful shots are fired ( like a real - life tank ) . More specifically , after AC is checked for a successful hit and before DR is checked to further reduce the damage , any incoming damage is immediately reduced by DT : Unlike in " " , damage can be completely negated by DT . In such a case , the player gets a message that an attack dealt " no damage , " which can be frustratingly common when using weaker weapons against power armor or Wanamingo s . " Fallout : New Vegas " . Mechanics . " Fallout : New Vegas " mostly moves away from the exclusive use of in " Fallout 3 " , towards Damage Threshold ( DT ) . Like in previous games , DT can function as an outright subtraction : if a shot is fired with a damage value of 40 against a DT of 10 , then 10 damage will be ignored . However , the sequence of calculations differs compared to previous games and makes the math a little bit more involved than in Fallouts 1 and 2 . Thus , no discussion of damage is complete without referring to the combined statistics of DR and , after it , DT . This is because , contrary to previous games , DR is applied first . The value after this adjustment depends on any DR a player has , which is capped to a DR of 85 ( 85 % ) . DT applies after that , with a limit : " final damage taken cannot be lower than 20 % of the basic attack " ( a term equal to " dam " argument given in Combat article ; see ) ; if lower , it is overwritten to these 20 % instead . So , to evaluate our earlier example , if a shot of damage 40 is fired against a character with 95 DR as well as the previous 10 DT , the damage is first reduced to 6 ( 95 DR is capped down to 85 % reduction , 40 × 0 , 15 = 6 ) , and then reduced by 10 . The final result ( - 4 ) is less than 20 % of the " base attack " ( 8 ) , so the damage is overwritten to 8 instead . < br > This example shows that DR of 80 % + is redundant , as the final damage can still be capped only by 80 % . Damage which is reduced to below the 20 % minimum value is indicated with a shield icon next to the health bar ( either the PC , or the non - player character ' s ) . When all of an enemy ' s DT ( if it ' s not 0 to begin with ) is overcome with armor piercing attacks , then a broken shield icon will appear in its place instead . The shield icon is shown during V . A . T . S . and on the HUD ' s health bars once damage has been inflicted upon a target and will remain for 3 seconds afterwards . The default value for DT is set at 0 ; this is then modified mainly by the DT value of worn . Other attributes can affect the DT value of a character , both permanently or temporarily . and can increase the player ' s DT , while the trait reduces it . When attacking , the use of can modify the target ' s DT either way , with Hollow Point generally increasing their DT , and AP decreasing it . Difficulty and critical damage impact . As with the , the difficulty multiplier of incoming damage is applied " after " the damage resistance and damage thresholds calculations . As an example , take damage ( 125 ) on very hard difficulty , where the inbound damage multiplier is ×2 . If the player has no DT or DR , the damage dealt by the monster is plain 250 hp . If the player has 40 DT and no DR , the damage becomes ( 125 – 40 ) × 2 = 170 ; if the sequence were altered ( DT subtracted " after " multiplier applied ) , the player would have received 210 damage instead . < br > This makes DT way more vital on higher difficulties . Unlike difficulty multiplier , the critical damage is applied " before " the impact of damage threshold calculations as it counts as the ' base damage ' . The deathclaw mentioned above deals additional ( " + " ) 125 damage when it crits , leading to an attack with the power of 250 on normal difficulty . With 40 DT , player suffers from 210 damage instead , leading to 420 damage on very hard difficulty . Comparison of Damage Threshold and Damage Resistance . Implications . DR factor becomes much more important in extreme cases . Vanilla deathclaw ( like any other enemy ) will completely ignore the DT factor if the Courier has 80 % + DR ( Med - X + Slasher + Battle brew combo gives 85 % ) and deal 50 damage in any case , against any DT tally ) , as the damage " cannot be lower than 20 % " of it ' s basic attack ( ( 125 × 0 . 2 = 25 ) × 2 ( very hard difficulty multiplier ) = 50 ) ; its critical damage will be capped at 100 instead . The armor indicator will appear upon the hit as well , confirming the deathclaw is dealing it ' s minimum possible damage . < br > It means that when the Courier has to deal with high damaging opponents ( like said deathclaws ) , the most reliable method is to increase DR to its maximum wearing no armor at all for faster movement – or the armor with the best possible buffs . If the player has no Battle brew ( → 50 % DR ) , then , against the said deathclaw , 37 . 5 DT is needed to cap creature ' s damage to its minimum ( 125 × 0 . 5 = 62 . 5 ; 62 . 5 – 37 . 5 = 25 ) . As a more extreme example , take from " Old World Blues " add - on . Its plasma damage is set to 300 ( equal to that of ) , becoming plain 600 on very hard difficulty . However , with 80 % + DR it ' s attack power is capped at 60 at normal and 120 at very hard difficulty , making it possible to survive several blasts for a high - level Courier . With 50 DT and no DR , surviving its attacks dealing 500 damage on very hard difficulty ( ( 300 – 50 ) × 2 ) is possible only on a very high level . With 50 % DR and 50 DT , the damage becomes 200 ( ( 300 × 0 , 5 – 50 ) × 2 ) on very hard difficulty . < br > Interestingly , although no DT and DR of 50 % makes very hard difficulty experience equal to no armor experience on normal difficulty , the DT factor alters the picture . If the normal difficulty deathclaw hits the player with no DR and DT of 40 , it deals 85 ( 125 – 40 ) damage ; however , the very high difficulty deathclaw hitting the Courier with 50 % DR and 40 DT deals 50 damage instead ( 125 * 0 , 5 – 40 = 22 , 5 ; → override to 125 * 0 , 2 = 25 ; 25 × 2 = 50 ( very hard multiplier applied ) ) . To sum up , high DT is enough against low - but fast - damaging opponents ( e . g . , any fast - firing humanoids ) unless they don ' t get critical hits ; however , enemies with powerful attacks ( mainly deathclaws and humanoids with explosives or single - action high - end weapon ) should be countered with maximum DR instead .