Delaware · Retirement Plan Contributions (Solo 401k)
Retirement Plan Contributions (Solo 401k) in Delaware (2026)
Contribute to a Solo 401(k) plan as both employer and employee, up to $69,000 annually. Delaware has a progressive income tax with a top rate of 6.6%, so a Delaware filer's combined marginal rate on the next dollar at $72,724 of income is about 28.6% (22% federal + 6.6% DE).
2026 savings example for Delaware
Planning estimate for a single filer earning $72,724 (Delaware median household income in LevyIO's state dataset) who removes $5,000 from taxable income. Federal tax uses the 2026 IRS brackets after the $16,100 standard deduction; DE tax uses the state brackets in LevyIO's dataset and assumes the state follows the federal treatment.
Estimated total savings
$1,430
Federal savings
$1,100
$7,169 → $6,069 · 22% bracket
DE state savings
$330
$3,569 → $3,239 · 6.6% marginal
Combined marginal rate
28.6%
≈ $286 saved per $1,000 deducted
Statutory maximum for this item in LevyIO's dataset: $69,000.
Federal × Delaware marginal rates (2026, single)
Gross-income ranges include the federal standard deduction. The DE column is the state marginal rate at the midpoint of each range. The last column is the tax saved per $1,000 deducted at that combined rate.
| Federal bracket | Gross income (single) | DE marginal | Combined | Per $1,000 |
|---|---|---|---|---|
| 10% | $16,100 - $28,500 | 4.8% | 14.8% | $148 |
| 12% | $28,500 - $66,500 | 5.55% | 17.55% | $176 |
| 22% | $66,500 - $121,800 | 6.6% | 28.6% | $286 |
| 24% | $121,800 - $217,875 | 6.6% | 30.6% | $306 |
| 32% | $217,875 - $272,325 | 6.6% | 38.6% | $386 |
| 35% | $272,325 - $656,700 | 6.6% | 41.6% | $416 |
| 37% | Over $656,700 | 6.6% | 43.6% | $436 |
Eligibility & forms
Self-employed individuals with no employees
- Both employee and employer contributions
- Plan must be established by Dec 31
- Contributions by tax filing deadline
Federal forms: Form 1040, Form 5500-EZ
Delaware filing notes
Take advantage of zero sales tax for major purchases. The state standard deduction is low ($3,250), so itemizing may help. Check reciprocity agreements with neighboring states.
Common mistakes: Exceeding contribution limits; Not establishing plan by year-end.
Frequently asked questions
How much can the Retirement Plan Contributions (Solo 401k) save a Delaware taxpayer in 2026?
In LevyIO's example, a single filer with $72,724 of income (the Delaware median household income in our state dataset) who removes $5,000 from taxable income saves about $1,100 in 2026 federal tax (22% marginal bracket) plus about $330 in Delaware tax (6.6% state marginal rate), roughly $1,430 combined. It is a planning estimate computed from the 2026 IRS brackets and LevyIO's DE bracket data, not a survey figure.
What is the Delaware income tax rate for 2026?
Delaware has a progressive income tax with a top rate of 6.6%. The DE standard deduction in LevyIO's dataset is $3,250 single / $6,500 married. No sales tax. Moderate income tax. Low property taxes (0.53%).
Who qualifies for the Retirement Plan Contributions (Solo 401k) in Delaware?
Self-employed individuals with no employees. The federal rules are the same in every state; the requirements are: Both employee and employer contributions; Plan must be established by Dec 31; Contributions by tax filing deadline. Delaware filers should confirm on the DE return whether the state follows the federal treatment.
Which forms do I file to claim the Retirement Plan Contributions (Solo 401k)?
Federal: Form 1040, Form 5500-EZ. Delaware: check the Delaware Division of Revenue instructions for the matching state schedule. Common mistakes: Exceeding contribution limits; Not establishing plan by year-end.
Retirement Plan Contributions (Solo 401k) in other states
Sources
Reviewed 2026-09-17. Estimates are educational planning figures computed from the IRS 2026 inflation adjustments and LevyIO's state bracket dataset; they are not tax advice.