Effect of Parental Leave on pay cheque

Need a bit of help calculating the effect of one days parental leave a month (for 6 months on my pay cheque). If I earn €4358.25 Gross and €2644.42 NET a month what effect would taking 4 days unpaid parental leave a month be on take home pay????

Is it as simple as deducting 20% of the end results or would my tax credits make it slightly less than this?

Thanks

Here is my attempt to calculate it. I am open to correction, if anyone sees an error in what I have worked out.

Your gross annual salary is €52,296. There are about 250 working days in the year, so your daily gross salary is approx 209.
I have assumed no pension contribution.

So your gross per month will go down by 209

You are paying tax at the marginal rate, and PRSI and USC, so the tax on the 209 will be 41% + 7% + 4% = 109 euro.

So your net pay will be reduced by €100 a month.

Sorry my first post was unclear - it would be one day per week so then is would work out at approx. €400 a month I suppose...

thanks a million for your help!