Here's the current elements:
WTC
Basic - 1800
Couple and lone parent - 1770
30hr element - 735
Disabled worker - 2405
Severe disability element - 1020
50+ return to work (16-29hrs) 1235
50+ return to work (30+hrs) 1840
Childcare
Max for 1 - 175 per week
Max for 2 or more - 300 per week
Entitlement is 80% of childcare costs.
CTC
Family element - 545
Baby addition - 545
Child element - 2085
Disabled child element - 2540
Severely disabled child element - 1020
Work out which elements you are entitled to and add up your total entitlement.
For eg. Family of four income of £25k,one parent working over 30hrs per week, two children over 1yrs old.
WTC entitlement:
Basic: £1800
couple and lone parent: 1770 (everyone is entitled to this, which one you get is only to show entitlement to childcare)
30hr element: 735
No childcare entitlement as only one parent working
CTC entitlement:
family element: 545
child element: 4170
Total award before deduction: 9020
That award is now tapered down according to income. the first £6420 is disregarded and the rest tapered by 39%
£25k - £6420 = 18580
18580 x 39% = 7246
so total award 9020 - 7246 = 1774 which is what they will receive.
This way of calculating isn't exact, computer does strange things with fractions of pennies ffs and is impossible to figure out. But calculating like this
I usually get within £10 either way of the actual award
In your neighbours case, the ammount to deduct from the income is actually higher than the award, but everybody earning less than I think £55k is entitled to the minimum family element whilst they have children.
Phew, that was a long post!