[Home](./index.md) > [bitburner](./bitburner.md) > [HackingFormulas](./bitburner.hackingformulas.md) > [weakenEffect](./bitburner.hackingformulas.weakeneffect.md) ## HackingFormulas.weakenEffect() method Calculate the security decrease from a weaken operation. Unlike other hacking formulas, weaken effect depends only on thread count and core count, not on server or player properties. The core bonus formula is . **Signature:** ```typescript weakenEffect(threads: number, cores?: number): number; ``` ## Parameters

Parameter	Type	Description
threads	number	Number of threads running weaken.
cores	number	_(Optional)_ Number of cores on the host server. Default 1.

**Returns:** number The security decrease amount.