Delaware child support calculator

How Delaware calculates child support

• Delaware uses the Melson formula. Each parent starts from gross income (no tax deduction) and subtracts limited deductions and a $1,600 Self Support Allowance. Nontaxable income other than Social Security counts 25% extra. A parent who supports other children keeps 70% of what is left.
• The children’s primary support need is $420 per child plus $380 per household, plus work-related child care, approved private-school costs and 75% of the children’s health insurance premiums. Each parent owes a share by income.
• Each parent then adds a Standard of Living Adjustment: 12% of remaining income for one child, 17% for two, 21% for three and 2% more for each additional child, with a 30% offset on income above $16,000 a month.
• Each parent is credited with the support they provide in their own home. A parent with 80 to 124 overnights keeps 10% of the other parent’s retained support, and 30% for 125 to 163 overnights; 164 or more overnights in each home is shared placement.
• No parent pays more than 50% of net available income (35% with children in three or more households). The minimum order is $160 for one child and $240 for two or more, except in shared or split placement.

What the calculator asks

• How many children is the support for?
• Where do the children live?
• How many overnights a year do the children spend with the parent they do not live with?
• How many of the children live mainly with you?
• Does any child spend 80 or more overnights a year with the parent they do not live with?
• Your monthly wages, salary, overtime and bonuses (all jobs)
• Your monthly self-employment income
• Can you document that you paid self-employment tax?
• Other taxable income you receive each month
• Nontaxable income you receive each month (not from Social Security)
• Mandatory retirement contributions taken from your pay each month
• Voluntary 401(k), 403(b), 457, TSP or similar contributions each month
• Union dues you pay each month
• Disability insurance premiums you pay each month
• Court-ordered alimony you pay each month
• Health insurance premiums you pay each month for policies that do NOT cover these children
• Other mandatory deductions your employer requires (uniforms, supplies)
• Do you support other children (your own children not in this case)?
• Do you support children living in three or more households?
• The other parent’s monthly wages, salary, overtime and bonuses (all jobs)
• The other parent’s monthly self-employment income
• Can the other parent document paying self-employment tax?
• Other taxable income the other parent receives each month
• Nontaxable income the other parent receives each month (not from Social Security)
• Mandatory retirement contributions taken from the other parent’s pay each month
• The other parent’s voluntary 401(k), 403(b), 457, TSP or similar contributions each month
• Union dues the other parent pays each month
• Disability insurance premiums the other parent pays each month
• Court-ordered alimony the other parent pays each month
• Health insurance premiums the other parent pays for policies that do NOT cover these children
• Other mandatory deductions the other parent’s employer requires
• Does the other parent support other children (not in this case)?
• Does the other parent support children living in three or more households?
• Work-related child care you pay each month for these children
• Work-related child care the other parent pays each month for these children
• Private-school tuition or other primary expenses you pay each month
• Private-school tuition or other primary expenses the other parent pays each month
• Health, dental and vision premiums you pay each month for policies that cover these children
• Health, dental and vision premiums the other parent pays each month for policies that cover these children
• Do the children receive Social Security disability benefits because of a parent’s disability?

It never asks for names, Social Security numbers or account numbers, and your answers are not saved.

What the estimate leaves out

• Social Security disability benefits paid to the children because of a parent’s disability (they offset that parent’s obligation dollar for dollar)
• Imputed income: Delaware uses each parent’s reasonable earning capacity, at least $2,390 a month when income is undocumented or a parent is un- or underemployed
• Support sought by a guardian or other nonparent
• Cash medical support: each parent’s share of uninsured medical costs is shown but not added to the monthly amount
• Arrears, retroactive support and the lower obligation for a disabled parent or after 180 days of incarceration
• Deviations the court may order when the formula is unjust or not in the child’s best interest (Rule 500(a))

When a situation is outside what the calculator covers, it says so and points you to the official worksheet instead of guessing.

Official sources

• Family Court Civil Procedure Rules 500–510, the Delaware Child Support Formula (as amended effective Feb. 1, 2023)
• Form 509i, Instructions for Child Support Calculation (2026), v1.02 rev. 2026-02-01
• Form 509, 2026 Delaware Child Support Formula worksheet, v2.01 rev. 2026-02-01
• Form 509C, 2026 Child Support Excel Calculator, v2.02 rev. 2026-02-01
• Delaware Child Support Formula Evaluation and Update, Report of the Family Court Judiciary (Nov. 4, 2022)

Delaware Family Court child support calculation (Form 509 and the Excel calculator) →