Retirement accounts are usually the largest marital asset, and you cannot divide them by writing a check. The mechanics differ by account type, and getting them wrong converts a tax-free division into a taxable disaster.
Employer plans governed by ERISA — 401(k), 403(b), and traditional pensions — require a Qualified Domestic Relations Order (QDRO), a separate court order drafted to the plan administrator’s specifications and approved by both the judge and the plan. Without it, “giving half my 401(k)” to an ex-spouse is a taxable distribution to you, plus the 10% penalty if you are under 59½. With it, the plan splits cleanly and the receiving ex-spouse — the alternate payee — owns their share directly.
The QDRO carries a feature worth knowing. A distribution paid to an alternate payee under a QDRO is exempt from the 10% early-withdrawal penalty ( IRC §72(t)(2)(C), “Tax on early distributions from qualified retirement plans”). It is the one moment an under-59½ spouse can pull cash out of a 401(k) penalty-free. The money is still ordinary income if it is not rolled over — but if liquidity is needed, take it at the QDRO stage, before the share is rolled into an IRA, because once it lands in the IRA that penalty exemption is gone (section “Early Withdrawal Penalty Minimization”).
IRAs work differently: no QDRO applies. An IRA is divided as a transfer incident to divorce under IRC §1041, “Transfers of property between spouses or incident to divorce”. Done correctly — the split spelled out in the divorce decree and moved trustee-to-trustee — it is a non-taxable event. Done as an ordinary withdrawal handed across the table, it is fully taxable to the original owner. The decree language is what makes it tax-free, so make it explicit. Government and military plans (the federal Thrift Savings Plan, FERS, and military pensions) use their own order formats, not the private-sector QDRO.
Finally, mind the tax character of what you split. Half a Roth IRA is worth more than half a traditional IRA of the same balance — one is after-tax money, the other carries a deferred tax bill. Divide account types proportionally, or price the embedded tax before you agree to the split.