[Home](./index.md) > [bitburner](./bitburner.md) > [HacknetServersFormulas](./bitburner.hacknetserversformulas.md) > [cacheUpgradeCost](./bitburner.hacknetserversformulas.cacheupgradecost.md) ## HacknetServersFormulas.cacheUpgradeCost() method Calculate cost of upgrading hacknet server cache. Signature: ```typescript cacheUpgradeCost(startingCache: number, extraCache?: number): number; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | startingCache | number | starting cache level | | extraCache | number | amount of levels of cache to purchase (defaults to 1) | Returns: number The calculated cost.