# How do I find the multiplier for a rate of exponential decay?

##### 1 Answer

This depends on what you already know. I'll do two examples:

**First to know** :

Decay follows the formula:

Where

**Simple** :

You know that decay is 5% per period. So after each period the value is only 95% of the period before. You "growth" (decay) factor is then

**Bit more complicated:**

A radio-active object has a half-life of 4 days, what is the decay-factor (per day)?

Which means it will lose almost 16% of its activity per day *(check!)*

**Extra** :

Instead of using

You key in x^(1/t) with the right numbers, e.g. 0.5^(1/4)