Estimate how a 401k splits in a divorce.
Of the 400 000 USD balance, 300 000 USD accrued during the marriage and is subject to division. A 50% split gives the other spouse 150 000 USD, leaving you 250 000 USD (including the 100 000 USD pre-marital portion).
Calculated in your browser using a simplified coverture split. State law varies (community-property vs equitable-distribution), and the split is enforced by a QDRO. An estimate only — not legal advice.
Formulas and content last reviewed . IRS limits change each year — confirm current figures at IRS.gov and with your plan administrator.
The short answer
In a divorce, usually only the portion of a 401k accrued during the marriage is divided. If the balance grew from $100,000 at marriage to $400,000, the $300,000 marital portion is split — often 50/50, giving the other spouse $150,000 and leaving the owner with $250,000. The pre-marital $100,000 typically stays with the original owner. The split is enforced by a Qualified Domestic Relations Order (QDRO), the court order that lets the plan divide the account without triggering the 10% early-withdrawal penalty or immediate tax. The valuation date used — marriage, separation, or divorce — is negotiated and can change the result significantly. One caveat: how the marital portion is divided depends on state law — community-property states lean toward an equal split, while equitable-distribution states divide it fairly, which is not always 50/50 — so this is an estimate, not legal advice.
Formula & method
Other spouse = (Current − At-marriage) × Split%
The marital portion is the growth in the account during the marriage; it is divided by the agreed percentage.
Subtract the balance at the date of marriage from the current balance.
That difference is the marital portion subject to division.
Multiply it by the agreed split percentage (often 50%).
The result is the other spouse's share; the rest stays with the owner.
Guide
The 401k value at the time of the divorce.
The account value on the date you married — the separate property.
The share of the marital portion going to the other spouse (commonly 50%).
The tool shows the marital portion and each spouse's estimated amount.
Examples
Inputs
Result
Only the $300,000 accrued during the marriage is divided; the pre-marital $100,000 stays yours.
Methodology
Uses a simplified coverture approach: only the balance accrued during the marriage is marital property.
Real orders may also allocate investment growth on the separate portion — rules vary by state.
Community-property states may treat the entire during-marriage balance as jointly owned regardless of who earned it.
This is an estimate, not legal advice — a QDRO must be drafted and approved by the plan and the court.
Contribution limits, catch-up amounts, the early-withdrawal penalty and RMD rules follow the Internal Revenue Code as administered by the IRS, using the published figures for the 2026 tax year. Confirm current limits at IRS.gov, as they are adjusted annually for inflation.
Primary sources
Details
A Qualified Domestic Relations Order (QDRO) is the legal document that directs the plan to split the 401k.
A properly executed QDRO transfer avoids the 10% early-withdrawal penalty and immediate tax.
State law decides what counts as marital vs separate property — equitable-distribution and community-property states differ.
The date used to value the account (marriage, separation, or divorce) is negotiated and matters a great deal.
The receiving spouse can usually roll their share into their own IRA or retirement account.
How it connects
Applications
Get a rough sense of how the 401k might divide before meeting an attorney.
Understand the difference between marital and separate property in the account.
Illustrate a proposed split quickly during settlement discussions.
Related tools
FAQs
Typically only the portion of the 401k accrued during the marriage is divided, and often — though not always — it is split 50/50. For example, if a 401k grew from $100,000 at the date of marriage to $400,000 at divorce, the $300,000 marital portion is divided, giving each spouse $150,000 of it, while the pre-marital $100,000 usually stays with the original owner. The division is carried out by a Qualified Domestic Relations Order (QDRO), a court order that lets the plan pay the other spouse without triggering the 10% early-withdrawal penalty or immediate tax. One caveat: the valuation date used — marriage, separation, or divorce — is negotiated and can shift the result significantly, and how the marital portion is divided depends on state law, so this is an estimate, not legal advice.
Security & privacy
Uses the current IRS contribution limits, penalty rules and RMD tables — updated for 2026.
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Knowing the marital vs separate portion changes the conversation. Enter the balances to see an estimated division — then confirm with an attorney.