What Moore/Marsden is
In California, a home one spouse bought before marriage starts as that spouse's separate property. When the mortgage is then paid down during the marriage with earnings, the community has paid for part of the home. Moore/Marsden is the formula California courts use to give the community a share of the home in proportion to that paydown, and a matching share of the appreciation during the marriage.
It is named for two cases. In re Marriage of Moore (1980) set out the community's share for a home bought before marriage and paid down during it. In re Marriage of Marsden (1982) applied it to a home that rose in value both before and during the marriage, leaving the appreciation before marriage with the owning spouse.
Only principal counts. Interest, property taxes, and insurance paid during the marriage do not add to the community's share.
The formula
- Community paydown = loan balance at marriage − loan balance at separation (less any traced separate payments)
- Community percentage = community paydown ÷ purchase price
- Appreciation during marriage = market value now − market value at marriage
- Community interest = community paydown + community percentage × appreciation during marriage
- Separate interest = the rest of the equity: down payment, principal paid before marriage, appreciation before marriage, and the separate percentage of appreciation during marriage
The community interest is then divided equally. The owning spouse keeps the separate interest plus half the community interest, and the other spouse receives the other half of the community interest.
The denominator is the full purchase price, not the down payment and not the loan. That choice is what the cases settled: the loan counts as the owner's separate contribution, because the owner took it on before the marriage.
A worked example
Fictional figures
Alex bought a condo for $500,000 with $100,000 down and a $400,000 loan. By the wedding the loan was down to $380,000 and the condo was worth $600,000. At separation the loan was $300,000, and it is worth $900,000 now.
| Step | Working | Amount |
|---|---|---|
| Community paydown | $380,000 − $300,000 | $80,000 |
| Community percentage | $80,000 ÷ $500,000 | 16% |
| Appreciation before marriage | $600,000 − $500,000, stays separate | $100,000 |
| Appreciation during marriage | $900,000 − $600,000 | $300,000 |
| Community interest | $80,000 + 16% × $300,000 | $128,000 |
| Equity now | $900,000 − $300,000 | $600,000 |
| Alex's separate interest | $600,000 − $128,000 | $472,000 |
| Alex's share | $472,000 + half of $128,000 | $536,000 |
| Spouse's share | half of $128,000 | $64,000 |
Check: $100,000 down + $20,000 paid before marriage + $100,000 appreciation before marriage + 84% × $300,000 = $472,000 separate
Where the numbers come from
- Purchase price and down payment: the closing statement from escrow.
- Loan balances: the mortgage statements nearest the dates of marriage and separation, or the lender's payoff history.
- Which account paid: the bank statements the mortgage payments came from. Earnings during marriage are community; an inheritance or premarital savings may be separate if it can be traced.
- Market values: an appraisal, or figures both sides agree on. A retrospective appraisal can estimate the value at the date of marriage.
The first three are records work. Gaps are common: a statement missing for the month of the wedding, a refinance that changed lenders, payments that came from more than one account. Those gaps are where a Moore/Marsden number is usually challenged.
What it leaves out
- Refinances. A refinance during the marriage, especially one that took cash out or was signed by both spouses, can change the calculation. This calculator does not model it.
- A home bought during the marriage. Moore/Marsden is for a home owned before marriage. Separate money put into a home bought during the marriage is usually a Family Code §2640 reimbursement instead.
- Title changes. If the home was put into both names during the marriage, the analysis may be different. Ask your attorney.
- Payments after separation. Mortgage payments made after separation are not part of this formula. They may support Epstein credits.
- Improvements and other adjustments. Remodels paid with community money, or the court's discretion in a particular case, are outside the formula.
Updated October 28, 2026. This page explains a published formula and does the arithmetic. It is not legal advice and does not decide whether any property is community or separate. Andluck is not a law firm or a CPA firm.
Sources
- In re Marriage of Moore (1980) 28 Cal.3d 366: the community's pro rata share for principal paid during marriage on a home bought before it, measured against the purchase price, excluding interest, taxes, and insurance.
- In re Marriage of Marsden (1982) 130 Cal.App.3d 426: appreciation before marriage stays separate; the community shares only in appreciation during marriage.
- In re Marriage of Epstein (1979) 24 Cal.3d 76: reimbursement for community debts paid with separate funds after separation.
- California Family Code §2640: reimbursement of separate contributions to community property.
- California Courts: Property and debts in a divorce: the general community and separate property framework.