To calculate the present value of future damages, you project what the injured person will lose in each future year, divide each year’s loss by (1 + r) raised to the number of years until that loss occurs, and add all those discounted figures together. The variable r is the discount rate, and the sum is the lump sum that, invested today at that rate, would fund each year’s loss as it comes due. The formula is straightforward. The fights are over the inputs.
The Year-by-Year Formula
A dollar received today is worth more than a dollar received years from now, because today’s dollar can be invested. For a single future payment, the present value equals the amount divided by (1 + r)^n, where r is the annual discount rate and n is the number of years until the payment is needed. A $50,000 loss expected ten years out, discounted at 2%, has a present value of about $41,020. The same $50,000 loss thirty years out drops to roughly $27,610.
A real damages calculation almost never involves one payment. A seriously injured plaintiff may face annual medical costs for decades plus lost wages every year until retirement. Each year gets its own calculation, because money needed in year three requires a larger deposit today than money needed in year twenty. The expert runs the formula for every year, then totals the individual present values. That total is the lump-sum award.
The projected losses themselves are not flat either. Wages tend to grow across a career, and medical costs climb faster than general inflation, so the numerator changes year to year. The expert has to forecast each year’s actual dollar loss before discounting it back. Errors on either side of the fraction compound across every remaining year of the plaintiff’s life.
The Inputs You Need Before You Run the Numbers
For lost wages, the documentation includes tax returns, W-2s, pay stubs, and 1099s for independent contractors and gig workers.1Office for Victims of Crime. Characteristics of Well-Supported Payment Amounts for Lost Wages and Loss of Support If the claim is for lost earning capacity rather than a fixed salary, the file also needs evidence of expected promotions, fringe benefits, and typical career trajectories in the plaintiff’s industry.
Future medical expenses are documented through a life care plan, which lays out every treatment, medication, therapy session, and piece of equipment the plaintiff will need for life, with associated costs. It takes input from multiple healthcare professionals who can tie each item to the plaintiff’s specific injuries with reasonable medical certainty.
How long do the losses run? Two different timeframes answer that. The CDC’s National Center for Health Statistics publishes period life tables estimating how many additional years a person of a given age can expect to live.2Centers for Disease Control and Prevention. Life Expectancy For lost wages, work-life expectancy tables from the Bureau of Labor Statistics factor in both mortality and the likelihood that a person of a given age, gender, and education level would have stayed in the workforce.3Bureau of Labor Statistics. Worklife Estimates – Effects of Race and Education The two numbers often diverge sharply. A 40-year-old might have a life expectancy of another 40 years but a work-life expectancy of only 22 more years, which means medical costs run much longer than the lost-income stream.
Picking a Discount Rate
The discount rate is the single most contested variable, because small changes produce large swings in the final number. Dropping the rate from 4% to 2% on a 30-year loss stream can add hundreds of thousands of dollars to the award. In Jones & Laughlin Steel Corp. v. Pfeifer, the Supreme Court declined to mandate a single method but identified three that courts can use.4Legal Information Institute. Jones and Laughlin Steel Corp v Pfeifer
Under the market interest rate method, the expert forecasts a specific future inflation rate, builds that inflation into the projected losses so they grow in nominal dollars, and discounts using the full market interest rate. The Court warned that specific inflation forecasts are often unreliable and can turn the process into a costly, unproductive waste.
Under the real interest rate method, the expert skips the inflation forecast, keeps the projected losses in today’s dollars, and discounts using a below-market rate that strips the inflation component out of nominal interest rates. The Court said it would not reverse a trial court that uses a real discount rate between 1% and 3%, as long as the court explains its choice.
Under the total offset method, inflation and wage growth are assumed to cancel out the discount rate, producing a net adjustment of zero. The plaintiff receives the undiscounted total of projected future losses. The Court called it simple but refused to make it mandatory.
Most forensic economists working in federal courts gravitate toward the real interest rate method because it avoids the speculative inflation forecast the market rate method demands while still preserving the time-value-of-money adjustment the total offset method eliminates. Long-term U.S. Treasury bonds have recently yielded around 4.8% on the 20-year maturity.5U.S. Department of the Treasury. Daily Treasury Par Yield Curve Rates Subtract a long-run inflation assumption of 2% to 3%, and you land in the 1.8% to 2.8% range, which fits inside the Court’s approved window.
Why One Inflation Rate Is Not Enough
Even when the expert uses the real interest rate method and skips an explicit inflation forecast for discounting, inflation still matters for projecting different categories of loss. Not all costs rise at the same speed. The Consumer Price Index for All Urban Consumers (CPI-U) tracks average price change across a broad basket of goods and services and covers more than 90% of the U.S. population.6U.S. Bureau of Labor Statistics. How to Use the Consumer Price Index for Escalation It works reasonably well for projecting wage growth and general living expenses.
Medical costs behave differently. Historically, medical inflation has outpaced general inflation by an average of about 1.7 percentage points, and it has exceeded general inflation roughly 87% of the time. An expert who applies the general CPI to a plaintiff’s future surgical and rehabilitation costs will systematically underestimate them. Credible damages reports use category-specific inflation rates, with medical expenses projected at a higher rate than wages or household expenses.
The discount rate and the inflation rate push the number in opposite directions. A higher discount rate shrinks the present value; higher projected inflation grows the future losses that feed the formula. Chosen honestly, both inputs produce a lump sum large enough to fund every year of projected loss if conservatively invested, but not so large that it hands the plaintiff a windfall.
Taxes Change the Number Twice
Taxes affect the calculation on both ends. On the front end, the Supreme Court held in Norfolk & Western Railway Co. v. Liepelt that income taxes must be considered when calculating lost future earnings, because a person’s ability to support their family depends on after-tax income, not gross pay.7Legal Information Institute. Norfolk and Western Railway Co v Liepelt The Court rejected the argument that tax evidence was too speculative for a jury. In practice, the expert should project after-tax earnings rather than gross earnings, which typically reduces the award.
On the back end, how the award itself is taxed depends on what it replaces. Damages for personal physical injuries or physical sickness are excluded from gross income under federal law, whether paid as a lump sum or in periodic payments.8Office of the Law Revision Counsel. 26 USC 104 – Compensation for Injuries or Sickness The exclusion covers the lost-wages component as long as the underlying claim arises from a physical injury. Punitive damages are always taxable. For non-physical claims such as employment discrimination, wrongful discharge, defamation, or emotional distress without physical injury, the IRS treats the entire recovery as taxable income, and it looks at the nature of the claim rather than the label the parties use in the settlement agreement.9Internal Revenue Service. Tax Implications of Settlements and Judgments
One trap: even when the award itself is tax-free, any interest, dividends, or capital gains the plaintiff earns after depositing the money are taxable. Since the entire present value calculation assumes the plaintiff will invest the lump sum to fund future losses, the tax drag on investment returns can erode the award faster than the projection assumed.
Mitigation Lowers the Lost-Earnings Input
A plaintiff cannot inflate a damages claim by doing nothing. The common-law duty to mitigate requires an injured person to take reasonable steps to minimize losses. If your injuries prevent you from doing your old job but you could perform lighter work, the projected lost earnings should reflect the income you could reasonably earn, not zero. Failure to mitigate is an affirmative defense, so the defendant has to raise and prove it.
Reasonable does not mean heroic. Courts do not expect a plaintiff to undergo risky surgery, accept a demeaning job, or spend more mitigating than the avoided loss would justify. Whether a plaintiff acted reasonably is a question for the jury. For the calculation, a credible economist will model a post-injury earning capacity based on what vocational evidence shows the plaintiff can realistically do, rather than defaulting to permanent total unemployment unless the medical evidence supports that.
Who Actually Runs the Numbers
Forensic economists and CPAs do the math and defend it in court. In federal cases, their written reports must comply with Rule 26 of the Federal Rules of Civil Procedure, which requires a complete statement of every opinion, the facts and data underlying it, the expert’s qualifications, a list of cases where they testified over the prior four years, and a statement of their compensation.10Legal Information Institute. Federal Rules of Civil Procedure Rule 26 Under the Daubert standard used in federal courts and many state courts, the judge acts as a gatekeeper on methodology. An expert who uses an unsupported discount rate or ignores present value entirely can be excluded before the jury hears a word.
Vocational rehabilitation experts handle the other half. The economist runs the financial model; the vocational expert evaluates what the plaintiff can actually do for a living after the injury by reviewing medical records, consulting with treating doctors, testing remaining skills, and surveying the local job market. The gap between pre-injury and post-injury earning capacity becomes the lost-earnings figure the economist feeds into the present value formula. Without vocational testimony, the projection rests on assumptions rather than evidence, which hands opposing counsel an obvious attack.
Structured Settlements Sidestep the Discount-Rate Fight
A structured settlement replaces the lump sum with a stream of guaranteed periodic payments funded by an annuity. Instead of arguing over discount rates and inflation assumptions, the parties negotiate a payment schedule shaped to the plaintiff’s actual needs: larger payments in years when major surgeries are expected, smaller ones during stable periods. Federal tax law treats periodic payments the same as a lump-sum award for physical injuries, so they are excluded from gross income, and the investment growth inside the annuity accumulates tax-free as well.8Office of the Law Revision Counsel. 26 USC 104 – Compensation for Injuries or Sickness That is an advantage a lump-sum plaintiff loses the moment they deposit the money and start earning taxable returns.
The trade-off is flexibility. A structure locks in the schedule. If circumstances change dramatically or an unexpected expense comes up, the plaintiff generally cannot accelerate or rearrange the payments. Some settlements split the difference, paying a larger initial lump sum for immediate debts and medical bills while structuring the remainder over decades. For plaintiffs who are concerned about managing a large sum responsibly, and for cases involving minors or adults with diminished capacity, structures offer built-in protection against spending the award too fast. The choice between lump sum and structure is a negotiation, and the present value calculation is the foundation for understanding what any proposed arrangement is actually worth.