Quick answer: In New Hampshire, either parent may apply to modify child support 3 years after the last order without showing a substantial change, and at any time on a substantial change. A change is effective only from notice of the petition, and it does not alter arrears due before the motion was filed.
This New Hampshire child support modification calculator applies RSA 458-C:7. Enter your current order and the amount the guidelines give today (you can get it from the New Hampshire child support calculator), say whether 3 years have passed, and it shows whether you must prove a substantial change, the monthly gap and what it adds up to after notice.
New Hampshire child support modification at a glance
| Rule | What New Hampshire says |
|---|---|
| Three-year route | Either parent may apply 3 years after the last support order without showing a substantial change (RSA 458-C:7, I(a)) |
| Any time | On a substantial change in circumstances (458-C:7, I(a)) |
| Start date | Not effective before notice of the petition was given: service as in civil actions, or accepted copy filed within 30 days (458-C:7, II) |
| Overpayment | The court orders the obligee to reimburse an overpayment that occurred after notice, absent undue hardship (458-C:7, III) |
| Arrears | No modification alters arrears due before the date the motion was filed (RSA 461-A:14, VIII) |
| Department reviews | The department notifies parties at least every 3 years of the right to request a review, and reviews TANF-assigned orders every 3 years (458-C:7, I(b)-(c)) |
How does child support modification work in New Hampshire?
- Know the two routes. See what counts as a substantial change in New Hampshire.
- File and give notice on time. See how to modify child support in New Hampshire.
- Income problems and incarceration. See lowering child support after job loss or incarceration in New Hampshire and, for what stays owed from before filing, the New Hampshire child support arrears calculator.
What does this modification calculator check?
The calculator tells you whether you need to prove a substantial change (within 3 years of the last order) or not (3 years or more), shows the monthly gap against the guideline amount and the accrued difference after notice. It cannot decide whether a court will find a substantial change. The months before notice are the ones you cannot recover.
Frequently asked questions
Do I have to show a change to modify New Hampshire child support?
Not if it has been 3 years since the last order for support; within 3 years you must show a substantial change in circumstances.
How soon can I modify New Hampshire child support?
At any time on a substantial change, and without one 3 years after the last order.
From what date can New Hampshire child support change?
Only from the date notice of the petition was given to the respondent.
Does a New Hampshire modification erase arrears?
No. A modification does not alter arrearages due before the date the motion for modification was filed.
What happens if I overpaid after notice in New Hampshire?
The court orders the obligee to reimburse the overpayment after notice, absent undue hardship, or adjusts the modified order.