diff --git a/src/NetscriptFunctions/Formulas.ts b/src/NetscriptFunctions/Formulas.ts
index 28161f1d1..a3861b647 100644
--- a/src/NetscriptFunctions/Formulas.ts
+++ b/src/NetscriptFunctions/Formulas.ts
@@ -175,7 +175,7 @@ export function NetscriptFormulas(player: IPlayer, workerScript: WorkerScript, h
         }
         return upg.getCost(level);
       },
-      hacknetServerCost: function (n: any, mult: any): any {
+      hacknetServerCost: function (n: any, mult: any = 1): any {
         checkFormulasAccess("hacknetServers.hacknetServerCost");
         return HScalculateServerCost(n, mult);
       },
diff --git a/src/ScriptEditor/NetscriptDefinitions.d.ts b/src/ScriptEditor/NetscriptDefinitions.d.ts
index 0bed2c63c..2d11ac4bc 100644
--- a/src/ScriptEditor/NetscriptDefinitions.d.ts
+++ b/src/ScriptEditor/NetscriptDefinitions.d.ts
@@ -3316,27 +3316,73 @@ interface SkillsFormulas {
 }
 
 /**
+ * Hacking formulas
  * @public
  */
 interface HackingFormulas {
-  hackChance(server: number, player: number): number;
-  hackExp(server: number, player: number): number;
-  hackPercent(server: number, player: number): number;
-  growPercent(server: number, threads: number, player: number, cores?: number): number;
-  hackTime(server: number, player: number): number;
-  growTime(server: number, player: number): number;
-  weakenTime(server: number, player: number): number;
+  /**
+   * Calculate hack chance.
+   * @param server - Server info from {@link NS.getServer | getServer}
+   * @param player - Player info from {@link NS.getPlayer | getPlayer}
+   * @returns The calculated hack chance.
+   */
+  hackChance(server: Server, player: Player): number;
+  hackExp(server: Server, player: Player): number;
+  hackPercent(server: Server, player: Player): number;
+  growPercent(server: Server, threads: number, player: Player, cores?: number): number;
+  hackTime(server: Server, player: Player): number;
+  growTime(server: Server, player: Player): number;
+  weakenTime(server: Server, player: Player): number;
 }
 
 /**
  * @public
  */
 interface HacknetNodesFormulas {
+  /**
+   * Calculate money gain rate.
+   * @param level - level of the node.
+   * @param ram - ram of the node.
+   * @param cores - cores of the node.
+   * @param mult - player production mult (default to 1)
+   * @returns The calculated money gain rate.
+   */
   moneyGainRate(level: number, ram: number, cores: number, mult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet node level.
+   * @param startingLevel - starting level
+   * @param extraLevels - amount of level to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   levelUpgradeCost(startingLevel: number, extraLevels?: number, costMult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet node ram.
+   * @param startingRam - starting ram
+   * @param extraLevels - amount of level of ram to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   ramUpgradeCost(startingRam: number, extraLevels?: number, costMult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet node cores.
+   * @param startingCore - starting cores
+   * @param extraCores - amount of cores to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   coreUpgradeCost(startingCore: number, extraCores?: number, costMult?: number): number;
+  /**
+   * Calculate the cost of a hacknet node.
+   * @param n - number of the hacknet node
+   * @param mult - player cost reduction (defaults to 1)
+   * @returns The calculated cost.
+   */
   hacknetNodeCost(n: number, mult: number): number;
+  /**
+   * All constants used by the game.
+   * @returns An object with all hacknet node constants used by the game.
+   */
   constants(): number;
 }
 
@@ -3345,13 +3391,65 @@ interface HacknetNodesFormulas {
  * @public
  */
 interface HacknetServersFormulas {
+  /**
+   * Calculate hash gain rate.
+   * @param level - level of the server.
+   * @param ramUsed - ramUsed of the server.
+   * @param maxRam - maxRam of the server.
+   * @param cores - cores of the server.
+   * @param mult - player production mult (default to 1)
+   * @returns The calculated hash gain rate.
+   */
   hashGainRate(level: number, ramUsed: number, maxRam: number, cores: number, mult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet server level.
+   * @param startingLevel - starting level
+   * @param extraLevels - amount of level to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   levelUpgradeCost(startingLevel: number, extraLevels?: number, costMult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet server ram.
+   * @param startingRam - starting ram
+   * @param extraLevels - amount of level of ram to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   ramUpgradeCost(startingRam: number, extraLevels?: number, costMult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet server cores.
+   * @param startingCore - starting cores
+   * @param extraCores - amount of cores to purchase (defaults to 1)
+   * @param costMult - player cost reduction (default to 1)
+   * @returns The calculated cost.
+   */
   coreUpgradeCost(startingCore: number, extraCores?: number, costMult?: number): number;
+  /**
+   * Calculate cost of upgrading hacknet server cache.
+   * @param startingCache - starting cache level
+   * @param extraCache - amount of levels of cache to purchase (defaults to 1)
+   * @returns The calculated cost.
+   */
   cacheUpgradeCost(startingCache: number, extraCache?: number): number;
+  /**
+   * Calculate hash cost of an upgrade.
+   * @param upgName - name of the upgrade
+   * @param level - level of the upgrade
+   * @returns The calculated hash cost.
+   */
   hashUpgradeCost(upgName: number, level: number): number;
-  hacknetServerCost(n: number, mult: number): number;
+  /**
+   * Calculate the cost of a hacknet server.
+   * @param n - number of the hacknet server
+   * @param mult - player cost reduction (defaults to 1)
+   * @returns The calculated cost.
+   */
+  hacknetServerCost(n: number, mult?: number): number;
+  /**
+   * All constants used by the game.
+   * @returns An object with all hacknet server constants used by the game.
+   */
   constants(): any;
 }