One check now, or seventy-two of them.
Money paid over years is worth less than the same total today, and maintenance can stop early. Enter the monthly amount, the months left, a rate of return, and the lump sum on the table, and see what each is worth and the rate at which they tie.
An assumption tool · 750 ILCS 5/510(c) on termination · Last reviewed September 7, 2026 · Facts · The table · Methodology
https://consideratecapital.com/tools/maintenance-buyout-calculator
The monthly amount in the order or the proposal.
The one-time payment offered instead of the monthly payments. Enter 0 if there is no offer yet.
The remaining term. For an Illinois case, the guideline calculator on this site gives the term the formula sets.
What the money could earn each year if invested. For the paying spouse, what it costs to borrow it.
Maintenance ends if the receiving spouse remarries or moves in with a partner, or if either spouse dies. Set it to 0 to ignore that.
- Value after the chance of stopping early
- $111,767
- 10% taken off for remarriage, cohabitation, or a death
- Monthly payment the lump sum would replace
- $1,772
- $110,000 spread over 72 months at 5%
- Rate at which the lump sum equals the payments
- 9.3%
- Above this rate the lump sum is worth more than the payments. Below it, less.
A lump sum trades certainty for size. The monthly payments end if the receiving spouse remarries or moves in with a partner, or if either spouse dies. The paying spouse can also ask the court to change them. A lump-sum property settlement paid in place of maintenance cannot be changed and survives remarriage. That is the whole trade. The chart draws the lump sum invested at the discount rate and paying out the same monthly amount, next to the value of the payments still owed.
This is an assumption tool, not a rule, and the discount rate and the chance of stopping early are yours to set. It assumes level payments at the end of each month, a lump sum paid today, no tax on what the lump sum earns, and an order entered after 2018, so that neither form is deductible to the payer or income to the receiver. It leaves out a later change to the monthly amount, interest on late payments, the cost of enforcing the order, and how each side would actually invest or borrow. Method reviewed September 7, 2026. Hypothetical; educational, not advice.
This is a simplified model, not your actual tax return or plan. It only knows what you type in, leaves out rules that may apply to you, and cannot weigh the other facts and trade-offs a real decision depends on. Before you act, talk with a professional who knows your whole situation.
Built by Joshua Mangoubi, CFA, MBA. By using this tool you agree to the tool terms, which include that results vary with each use and over time. Cite this tool, or take a table or chart
How it counts. Each remaining payment discounted at the rate you set and summed, less a plain allowance for the chance the payments end early; the lump sum divided by the same factor to give the monthly payment it would replace; and the crossover rate found by search.
What it assumes. Level payments at month end, a lump sum paid today, no tax on its earnings, and a post-2018 order so tax does not tip the comparison. The discount rate is the whole argument, and each side has a different one; whether a lump sum is a property settlement or maintenance, and what that does to modification and remarriage, is the family law attorney's to draft.
Where we fit in. We integrate tax considerations into your investment strategy and collaborate with estate attorneys and CPAs to ensure your plan is coordinated. We are not a law firm or accounting firm, so we do not provide legal or tax advice. Everything in this material is for educational purposes, based on primary sources. Before taking any action, please consult the appropriate professionals to apply these ideas to your situation.
The facts, in one place.
Six quotable sentences on trading maintenance for a lump sum.
- A stream of monthly maintenance and a lump sum paid today are compared at a discount rate: the return the recipient could earn on the money, or the cost of the money to the payor. The present value of the stream is the lump sum that, invested at that rate, would pay out the same amount for the same months.
- Maintenance is not a sure thing. Unless the parties agree otherwise in writing, it ends on the recipient's remarriage or cohabitation on a resident, continuing conjugal basis, or on either party's death (750 ILCS 5/510(c)), and the amount can be modified on a substantial change in circumstances. A lump-sum property settlement in lieu of maintenance is non-modifiable and survives remarriage; that is the trade.
- Example: $2,000 a month for 72 months is $144,000 in all. At 5% it is worth $124,186 today, and $111,767 after a 10% allowance for the payments ending early. A $110,000 lump sum would replace $1,772 a month over the same term, and the two are equal at a rate of 9.3%.
- The crossover rate is the number to argue about. Below it the payments are worth more than the lump sum on offer; above it, less. Each side's own rate is different, which is why a buyout can suit both.
- For an instrument executed after 2018, neither form is deductible to the payor or income to the recipient (Pub. L. 115-97 § 11051), so tax does not tip the comparison; what the lump sum earns once invested is taxed in the ordinary way and is not modeled here.
- A buyout also settles the future: no petitions to modify, no proof of cohabitation, no life insurance to secure the payments. Those costs are real and unpriced, and they run in both directions.
The stream by discount rate.
How the value moves with the one assumption that matters most.
| Discount rate | Value of the payments today | After the 10% allowance | Monthly payment $110,000 would replace |
|---|---|---|---|
| 3% | $131,634 | $118,470 | $1,671 |
| 4% | $127,835 | $115,051 | $1,721 |
| 5% | $124,186 | $111,767 | $1,772 |
| 6% | $120,679 | $108,611 | $1,823 |
| 7% | $117,309 | $105,578 | $1,875 |
| 8% | $114,069 | $102,662 | $1,929 |
How the comparison works.
A stream of monthly maintenance and a lump sum today are the same thing in different shapes only at one rate of return. Below that rate the payments are worth more; above it, the lump sum is. The calculator discounts each remaining payment at the rate you set and adds them up, which is the present value of the stream: the sum that, invested at that rate and drawn down by the same monthly amount, would last exactly the term. The chart draws that drawdown beside the shrinking value of the payments still owed.
Two things make the stream worth less than its arithmetic. Unless the parties agree otherwise in writing, maintenance ends on the recipient's remarriage or cohabitation on a resident, continuing conjugal basis, or on either party's death, and it can be modified on a substantial change in circumstances; the stop-early allowance is a plain haircut for that. A lump-sum property settlement in lieu of maintenance is non-modifiable and survives remarriage, which is why a payor will pay something for it and a recipient will accept something less than the face total. Since 2019 neither form is deductible or taxable, so the comparison is pre-tax on both sides; what the lump sum earns once invested is taxed in the ordinary way and is not modeled.
Methodology.
- Inputs. The monthly amount, the months left, a yearly discount rate, an allowance for the chance the payments stop early, and a proposed lump sum.
- The value today. Each remaining payment discounted at the monthly rate (the yearly rate over twelve), payments at month end: the ordinary annuity factor times the monthly amount. At a zero rate, the face total.
- The allowance. The value today times one minus the stop-early chance. A single haircut, not a month-by-month hazard.
- The lump sum's equivalent. The lump sum divided by the same annuity factor: the level monthly payment it would fund over the same months at the same rate.
- The crossover. The yearly rate at which the stream's value equals the lump sum, by bisection; none when the lump sum is at or above the face total.
- The drawdown. The lump sum grown at the monthly rate and reduced by the monthly amount, month by month, with the month it runs out marked when it does.
- Validation. The face total at a zero rate; a lump sum equal to the value at 5 percent funding exactly the same payment, crossing over at exactly 5 percent, and running out in the final month; the allowance as a plain 10 percent; the closed-form value at 5 percent; and a smaller lump sum running out early with a higher crossover. A transcription error fails the build.
- Not modeled. Tax on the lump sum's earnings, a later modification of the amount, interest on arrears, enforcement costs, life insurance securing the payments, the payor's creditworthiness, a lump sum paid in installments, and the property-division consequences of characterizing the payment. Hypothetical throughout. Educational, not advice.
Revision history.
The maintenance record's history.
- September 7, 2026
- First release: the Illinois maintenance guideline (the 33 1/3 percent less 25 percent formula, the 40 percent ceiling, the duration table, the $500,000 gate) on an approximation of the standardized net income, and the maintenance buyout comparison (present value of the stream at a discount rate, the stop-early allowance, the lump sum's monthly equivalent, and the crossover rate).
Canonical address: https://consideratecapital.com/tools/maintenance-buyout-calculator
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