How much child maintenance should he pay?

Hi can anyone give me an idea of how much maintenance my ex should pay?

We have 2 children.
He earns 42k a year.
He has no other children and is not responsile for any other children.
He has our childre over night about 26 - 40 nights a year.

I have tried using the CSA Calculator but am finding it difficult to work out his take home pay.

Any ideas how much it should be?

Thanks.

The system is due to change in October to be based on gross pay rather than net pay.

As a (extremely) rough estimate under the current scheme I would expect around £115 per week.

I based this calculation on a salary of £42k with deductions of around 30% for tax, national insurance, pension contributions etc.

For 2 children he has to pay 20% of what''s left. That makes around £5600 which divided by 52 is around about £115 per week. If he has the children less than 52 nights per year and does not live with any other children he has care of then there are no deductions to this figure.

I don''t know what the percentage of his gross pay will be under the new scheme, I''m not sure it''s officially been announced yet. If anyone would know then Fiona will!

Thank you that''s very helpful.

its looking like it will be 16% for two children on the first £800 per week then 12% on anything over that.

Your ex just goes over £800pw barrier but I assume he pays into a pension scheme?

Assuming he pays 10% of his earnings into a pension so pays 16% of £37800 it works out at about £115pw!

Could be slightly more or less depending on pension contributions but I think they are capping them at 15% anyway so if he paid the max into his pension it would be about £110 per week for CSA.