A child born outside marriage appears after the estate is settled: check the amount and the deadline first
This calculator is based on Korean rules: the 2026 Korean Civil Act and Korean Supreme Court case law.
Sometimes a father dies, the heirs divide the estate and even sell part of it, and only later does an acknowledgment judgment make a child born outside marriage a co-heir.
That child cannot undo the completed division, but under Civil Act Article 1014 the child may claim the value of their inheritance share in money.
The Korea acknowledged-child inheritance value claim calculator estimates that amount and the exclusion-period deadline as a preparation tool.
Who this is for
- A child born outside marriage, or their legal representative, preparing an acknowledgment suit after the father’s death or holding a final acknowledgment judgment
- A surviving spouse or children who already divided or sold the estate and now face a value claim
- Existing heirs who want to test a case-law-based figure and common mistakes before proposing a settlement
- Families asking what percentage the acknowledged child receives and when the claim period ends
Main features and scope
- Calculates the acknowledged child’s statutory share as a fraction and a percentage from whether a spouse survives and how many existing children there are.
- Builds a target-value ledger from up to five divided or disposed assets with current value, the heir who took each asset and any actual sale price.
- Deducts inheritance tax including penalties, does not deduct capital gains tax paid on a sale, and excludes fruits such as rent received after the division.
- Shows the two-year acknowledgment-suit deadline, the three-year value-claim deadline, the days left, and whether ten years have passed since the inheritance opened.
- Splits the payment between existing heirs two ways: by statutory shares and by the value each heir acquired.
- Shows in KRW how far three common mistakes move the claim: adding fruits, deducting sale taxes and using sale prices.
It does not predict whether parentage will be established, what a court appraisal will find or how a court will split the burden between heirs.
Concrete shares adjusted for contribution and special benefits, forced heirship, tax recalculation and deduction of inherited debts are outside the scope.
Use the result as an estimate to prepare for advice and negotiation.
What kind of right is the Article 1014 value claim?
An acknowledgment takes effect retroactively from birth, but it cannot harm rights already acquired by third parties (Civil Act Article 860, proviso).
Article 1014 therefore leaves divided or disposed assets where they are and instead lets the child receive the value of their share in money.
The Supreme Court treats this right as a kind of inheritance recovery claim (Supreme Court 93Da12, decided 1993-08-24).
Assets already divided or disposed of
Ownership of the heir who received the asset, or of the buyer, stays final.
The acknowledged child claims payment of the value of their share, not the return of the asset.
The calculator’s claim covers this part only.
Assets not yet divided
For property still undivided, the acknowledged child joins the division directly alongside the other heirs (Supreme Court 2006Da83796, decided 2007-07-26).
The calculator keeps undivided property out of the value claim and shows only a statutory-share reference figure.
The acknowledged child’s share by family composition
A child born outside marriage is a first-rank lineal descendant with the same share as a child born in marriage.
When inheriting with lineal descendants, the spouse receives the descendant share plus 50% (Civil Act Article 1009(2)).
So the acknowledged child’s share = 1 ÷ (spouse 1.5 + number of existing children + 1).
Weight total, acknowledged child share, percentage and claim on a KRW 1 billion target value by family composition| Heirs (including the acknowledged child) | Weight total | Child’s share | Percentage | On KRW 1 billion |
|---|
| Spouse + 1 existing child | 3.5 | 2/7 | 28.57% | 285,714,286 KRW |
| Spouse + 2 existing children | 4.5 | 2/9 | 22.22% | 222,222,222 KRW |
| Spouse + 3 existing children | 5.5 | 2/11 | 18.18% | 181,818,182 KRW |
| Spouse + 4 existing children | 6.5 | 2/13 | 15.38% | 153,846,154 KRW |
| No spouse + 1 existing child | 2 | 1/2 | 50.00% | 500,000,000 KRW |
| No spouse + 2 existing children | 3 | 1/3 | 33.33% | 333,333,333 KRW |
| No spouse + 3 existing children | 4 | 1/4 | 25.00% | 250,000,000 KRW |
Substitute heirs of a child who died first inherit that one child’s portion, so count them as one branch (Civil Act Article 1010).
A child who renounced is treated as never having been an heir, so leave them out of the existing-children count.
If there are no existing children and parents or siblings inherited, the acknowledged child displaces them, which is outside this calculator’s scope.
What goes into the target value, what is deducted and what is not
Claim = (current value of divided or disposed assets − inheritance tax paid) × the acknowledged child’s share.
One wrong entry can move the figure by tens of millions of KRW, so check each item against case law.
Included: value at the close of argument
The value is the market value when argument closes at the fact-finding court, not the actual sale price or the value at disposal (93Da12).
So land sold years ago for KRW 240 million counts at KRW 300 million if that is its current value.
Deducted: inheritance tax and penalties
Inheritance tax necessarily paid to acquire the estate is deducted, including late-filing and late-payment penalties (Supreme Court 2006Meu2757, 2764, decided 2007-07-26, point [7]).
Other costs, such as an accountant’s fee for a tax appeal, were not deducted.
Not deducted: taxes paid on a sale
Capital gains and other taxes paid when an heir sold an estate asset are not a cost of the inheritance and are not deducted (93Da12).
The existing heirs cannot ask the acknowledged child to reimburse that tax either.
Excluded: fruits arising after division
Rent from a divided apartment or dividends on shares arise after the division, are not estate property and are not counted (2006Meu2757 point [5], 2006Da83796).
The scope does not change depending on whether the other heirs knew the child existed (93Da12).
In 2006Meu2757 the lower court converted inheritance tax paid over several years to its value at the close of argument using the consumer price index.
The calculator uses the tax amount you enter, so if it was paid long ago, enter a converted figure to compare.
When undivided property also exists, you can deduct the full tax or pro-rate it by value; pro-rating is an interpretive option, not a rule fixed by case law.
Exclusion periods: two years to sue for acknowledgment, three years for the value claim
There are two deadlines in sequence.
After the father’s death, the acknowledgment suit must be filed against the prosecutor within two years of learning of the death (Civil Act Article 864).
Once the acknowledgment judgment is final, the child is treated as knowing of the infringement on that day and must bring the value claim within three years of finality (Civil Act Article 999(2), 2006Meu2757 point [1]).
Acknowledgment-suit deadline = the same calendar date two years after learning of the father’s death
Value-claim deadline = the same calendar date three years after the judgment became final
Counting = skip the first day, end the day before the matching start date in the final year, or the month’s last day if there is no matching date (Civil Act Articles 157 and 160)
Ten-year limit = does not apply to Article 1014 claims (Constitutional Court 2021Hun-Ma1588, 2024-06-27, held unconstitutional)
For example, if the acknowledgment judgment became final on 2026-05-12, the value-claim deadline is 2029-05-12.
That date is a Saturday, so Civil Act Article 161 may move it to the next weekday, but the calculator counts days to the unadjusted date so the deadline is not missed.
The Constitutional Court held that barring the claim entirely ten years after the infringement violates property rights and the right to a trial, noting that the two-year acknowledgment period and the three-year value-claim period already limit timing twice.
A mother’s estate works differently
Article 1014 does not apply to a mother–child relationship
Between a child born outside marriage and the birth mother, a legal parent–child relationship arises at birth without any acknowledgment.
The Supreme Court held that the Article 860 proviso does not apply to that relationship and that Article 1014 does not prevent the child from challenging the division or disposal (Supreme Court 2018Da1049, decided 2018-06-19).
So when the mother has died, the route is not a value claim but challenging the division made without the child and seeking a new division.
If you select the mother as the deceased parent, the calculator shows route guidance and a statutory-share reference figure instead of a deadline.
Step-by-step use
- Choose the perspective and parent: select whether you are the acknowledged child or an existing heir, and whether the deceased parent is the father or the mother.
- Acknowledgment stage and dates: enter the date you learned of the death before filing, or the finality date once the judgment is final, plus the inheritance date.
- Heirs: select whether a spouse survives and the number of existing children excluding the acknowledged child.
- Asset ledger: enter each divided or disposed asset’s current value and who took it, and record any actual sale price for comparison.
- Deductions and exclusions: enter inheritance tax with penalties, undivided property, taxes paid on sales and rent received after the division, then choose the appraisal sensitivity.
- Save the result: review the claim, deadline and two payment splits, then save a TXT report or print it for your consultation.
Changing any input hides the previous result, so recalculate with confirmed figures.
No names, resident registration numbers or case numbers are collected, and inputs are not sent to a server or stored.
Worked example: a spouse, two existing children and one acknowledged child
Claim in the fictional example
The spouse took an apartment (current value KRW 700 million), the elder son took land (KRW 300 million, later sold for KRW 240 million) and the daughter took deposits and shares (KRW 200 million), KRW 1.2 billion in total.
After deducting KRW 100 million of inheritance tax the target value is KRW 1.1 billion, and multiplying by the 2/9 share gives a claim of 244,444,444 KRW.
If the appraisal moves ±10%, the claim ranges from 217,777,778 KRW to 271,111,111 KRW.
What common mistakes change
Valuing the land at its KRW 240 million sale price instead of current value cuts the claim by 13,333,333 KRW.
Deducting KRW 30 million of sale tax wrongly cuts it by 6,666,667 KRW, while adding KRW 45 million of rent wrongly raises it by 10,000,000 KRW.
Both sides should know these gaps so a settlement does not drift from the case-law basis.
In the fictional example the judgment became final on 2026-05-12 and the as-of date is 2026-11-02, leaving 922 days to the 2029-05-12 deadline.
The dates and amounts illustrate the features and do not describe any real family or case.
Splitting the payment between existing heirs and preparing a settlement
Case law has not fixed a single way to divide the payment between existing heirs.
The calculator therefore shows two bases side by side and notes that the final split is for the court.
Statutory-share basis
Splits by weights of 3 for the spouse and 2 for each child.
In the fictional example the spouse pays 104,761,904 KRW and each existing child 69,841,270 KRW.
Acquired-value basis
Splits by the current value of what each heir actually took.
In the fictional example the spouse pays 142,592,592 KRW, the son 61,111,111 KRW and the daughter 40,740,741 KRW.
Assets disposed of jointly or held in shares are attributed to each heir’s acquired value by statutory shares.
Whole-KRW remainders use the largest-remainder method, so the parts always add up exactly to the claim.
Existing heirs should first agree an internal split between the two bases, then review a settlement draft and any inheritance-tax correction claim with a tax adviser.
Points that are easy to miss
A partial claim must reserve expansion in advance
If only part is claimed within the period and the claim is increased after it ends, the added part is generally extinguished.
But if the claim identifies every asset divided or disposed of before the acknowledgment and states in advance that it will expand after the appraisal, the expanded part is also timely (2006Meu2757 point [2]).
Late-payment interest on the expanded amount runs from the day after the amendment is served (point [8]).
Inherited debts and contribution shares need separate review
No Supreme Court ruling deciding whether inherited debts are deducted from the value was found, so the calculator does not deduct them.
Money debts pass to heirs by statutory share automatically, so the acknowledged child may owe their own portion.
The 2021Hun-Ma1588 decision also noted that if existing heirs specially contributed to keeping or increasing the estate, a contribution-share decision can balance the interests.
Check tax treatment and the proper court
Uijeongbu District Court case 2023Gudan5804 (decided 2025-01-22) is summarized as holding that a mediated settlement received through a value claim is not subject to capital gains tax as a transfer.
Individual facts can change the outcome, so confirm the treatment of the amount received and the existing heirs’ inheritance tax with a tax adviser.
93Da12 and 2006Da83796 were civil cases, while 2006Meu2757 was heard with family-court estate division and contribution-share claims, so decide the court with a lawyer.
Frequently asked questions
Is a child born outside marriage entitled to the same share as a child born in marriage?
Yes.
An acknowledged child is a first-rank lineal descendant and children share equally.
The spouse receives 1.5 times a child’s share.
Can the child claim assets that were already sold?
The asset itself cannot be recovered, but the value of the share can be claimed in money.
The value is the market value at the close of argument, not the sale price.
When does the exclusion period for the value claim end?
Three years from the date the acknowledgment judgment became final.
The acknowledgment suit itself must be filed within two years of learning of the father’s death.
The ten-year limit from the inheritance does not apply to Article 1014 claims.
Why is inheritance tax deducted but sale tax is not?
Inheritance tax is a cost necessarily incurred in acquiring the estate, so it is deducted.
Sale tax arises when another heir disposes of an asset, and the Supreme Court did not deduct it.
Does rent from a divided apartment have to be shared?
No.
Rent, dividends and other fruits arising after division or disposal are not estate property, are not counted and are not unjust enrichment under case law.
Is the calculation the same if the mother died?
No.
A mother–child relationship needs no acknowledgment, so Article 1014 does not apply.
Review challenging the division made without the child and seeking a new division with a lawyer.
Can I file before the appraisal result is known?
Yes.
A partial claim that identifies every target asset and states it will expand after the appraisal keeps the expanded part within the period.
How much does each existing heir pay?
Case law has not fixed the method.
The calculator shows a statutory-share basis and an acquired-value basis, and the final split is for the court.
Laws and rulings checked, and when to update
Checked 2026-10-31 against the Korean National Law Information OPEN API for current status, full article text and case summaries.
The Civil Act in force is Act No. 21454 effective 2026-03-17 (MST 284415), and Article 999(2) carries the 2021Hun-Ma1588 unconstitutionality note.
- Civil Act Articles 157, 160, 161, 859, 860, 864, 999, 1009, 1010 and 1014, MST 284415
- Family Litigation Act Article 2 (acknowledgment suits in category Na, estate division and contribution shares in category Ma), MST 265309
- Supreme Court: 93Da12 (1993-08-24) · 2006Meu2757, 2764 (2007-07-26) · 2006Da83796 (2007-07-26) · 2018Da1049 (2018-06-19)
- Constitutional Court: 2021Hun-Ma1588 (2024-06-27) · lower-court reference: Uijeongbu District Court 2023Gudan5804 (2025-01-22)
The succession chapter is amended often, and legislation may replace the struck ten-year period.
Articles 999 and 1014 are rechecked yearly and on amendment; this tool does not replace a legal opinion or a court decision.
Once you know the deadline and the amount, decide what to do today
If you are the acknowledged child, prepare a complaint or mediation application that identifies every target asset before the deadline, and obtain the estate list and registry records first.
If you are an existing heir, gather inheritance-tax receipts, sale contracts and current valuations, and agree an internal split using both bases.
Save the result as a TXT report and bring it to your family-law attorney and tax adviser as supporting figures.
To recheck statutory shares and inheritance order, use the inheritance share calculator; for re-division settlement payments, use the inherited asset allocation and equalization calculator.
For paternity test costs before an acknowledgment suit, see the paternity DNA test cost calculator, and if lifetime gifts reduced your portion, see the forced heirship claim calculator.