Deferred Annuity Calculator
Model both halves of a deferred annuity — how your balance grows before payout begins, and either your withdrawal amount or how long those withdrawals will last.
How a deferred annuity actually works
A deferred annuity is built around two distinct phases. During the accumulation phase, you contribute money — a lump sum, ongoing monthly payments, or both — and the balance grows at an expected rate of return, typically tax-deferred, meaning you don't owe income tax on the growth until you actually withdraw it. Once accumulation ends, the payout phase begins, converting your accumulated balance into a stream of regular withdrawals rather than one large payment.
This is what separates a deferred annuity from an immediate annuity, where payments start right away after a single lump-sum purchase with no accumulation period at all. Deferred annuities are commonly used as a long-term retirement savings vehicle, including tax-deferred annuity (TDA or 403(b)) plans offered by certain nonprofit and education employers.
The deferred annuity formulas
Accumulation phase
FV = Lump Sum × (1+i)ⁿ + (PMT/i) × ((1+i)ⁿ − 1) × (1+i)
FV is the balance at the start of the payout phase, PMT is your regular contribution, i is the periodic interest rate, and n is the number of periods until accumulation ends. This calculator applies it monthly, compounding your lump sum and contributions together across the full deferral period.
Payout phase
a = PV ÷ (1 − (1 + i/k)⁻ⁿˣᵏ) × (i/k)
PV is the balance at the start of the payout phase (the FV from above), a is your regular withdrawal, i is the annual rate, k is the number of withdrawals per year, and n is the number of years you plan to withdraw. Rearranged, this same formula solves for how long a chosen withdrawal amount will last instead.
Worked example: $20,000 lump sum, $500/month, 20-year deferral
At a 6% annual accumulation rate compounded monthly, this contribution pattern grows to an estimated balance of roughly $305,000 by the start of the payout phase — made up of about $140,000 in total contributions and $165,000 in compounded growth. Choosing a 20-year payout phase at a 5% rate of return during withdrawals produces an estimated monthly withdrawal of roughly $2,000, fully depleting the balance by the end of that 20-year period.
Switch the question instead to "how long will it last" with a fixed $1,500 monthly withdrawal on that same balance, and the payout phase stretches out well beyond 20 years — illustrating how sensitive payout duration is to the specific withdrawal amount chosen relative to the balance and rate of return.
Types of deferred annuities
| Type | How Returns Work |
|---|---|
| Fixed Deferred Annuity | Guaranteed interest rate set by the contract, similar to a CD with tax-deferred growth. This is the structure this calculator models. |
| Variable Deferred Annuity | Contributions invested into selected funds; return depends on market performance rather than a guaranteed rate. |
| Equity-Indexed Annuity | A fixed annuity with a minimum guaranteed return plus a bonus tied to a stock index's performance, subject to a participation rate. |
| Longevity Annuity | A long-life-expectancy insurance product, deferring payout to a much later, fixed future age rather than a set number of years. |
Funding contributions, and weighing where extra income goes
Bigger contributions during the accumulation phase compound into a meaningfully larger balance by the time payout begins, which is exactly why extra income sources are worth directing toward this kind of long-term savings when possible. If overtime is part of your income, the no tax on overtime calculator can help you see how much extra take-home pay recent overtime tax changes might free up — money that could go straight into a higher monthly annuity contribution instead of being absorbed elsewhere.
On the other side of the ledger, if a big-ticket purchase like a leased vehicle is competing with your annuity contributions for the same monthly budget, the money factor calculator converts a lease's money factor into a real annual interest rate, making it easier to compare the true cost of that lease against the long-term value of directing that same money into your annuity's accumulation phase instead.
Deferred annuity calculator — FAQ
What is a deferred annuity, exactly?
A deferred annuity is a contract, typically with an insurance company, where you contribute money now and receive regular income or a lump sum starting at some point in the future rather than immediately. It has two distinct phases: an accumulation phase where your contributions grow, usually tax-deferred, and a payout phase where you begin receiving withdrawals. This is different from an immediate annuity, where payments begin right away after a single lump-sum purchase.
What's the difference between the accumulation phase and the payout phase?
The accumulation phase is the growth period — you contribute a lump sum, ongoing payments, or both, and the balance compounds at an expected rate of return without withdrawals. The payout phase begins once accumulation ends, converting the accumulated balance into a stream of regular withdrawals, calculated so the balance either depletes over a specific timeframe or, in some cases, is drawn down slowly enough to last indefinitely.
What does "tax-deferred" mean for this type of annuity?
Tax-deferred means you don't pay income tax on the interest or investment gains your annuity earns during the accumulation phase — that tax bill is postponed until you actually withdraw the money during the payout phase. This is one of the main appeals of deferred annuities as a retirement savings vehicle, similar in spirit to how a traditional 401(k) or IRA defers taxes until withdrawal, though the specific tax treatment of annuities has its own rules separate from those retirement accounts.
What's the difference between a fixed and variable deferred annuity?
A fixed deferred annuity earns a guaranteed rate of return set by the insurance contract, functioning similarly to a certificate of deposit but with tax-deferred growth. A variable deferred annuity instead invests your contributions into funds you select, meaning your return depends on market performance and isn't guaranteed — offering higher potential growth alongside real investment risk. This calculator models a fixed-rate structure, using whatever expected rate of return you enter for each phase.
How do I decide between solving for withdrawal amount versus payout duration?
Use "How much can I withdraw" if you already know how long you want the payout phase to last — for example, planning withdrawals over a 20-year retirement — and want to know the regular amount that fully depletes the balance by the end of that period. Use "How long will it last" instead if you already know how much you want to withdraw each period and want to see how many years that withdrawal amount can be sustained before the balance runs out.
Can a withdrawal amount be too small to ever deplete the balance?
Yes — if your chosen withdrawal amount is smaller than the interest the balance earns each period, the account never runs out, since the interest replenishes the balance faster than withdrawals draw it down. In that scenario, this calculator will flag that the balance can sustain withdrawals indefinitely at that amount, rather than returning a finite depletion timeline.
Does this calculator account for annuity fees or surrender charges?
No — this calculator models the underlying accumulation and payout math using your specified interest rates only, not the fees, mortality and expense charges, or surrender penalties that real annuity contracts often include. Actual annuity products can carry meaningful fee structures that reduce net returns compared to this calculator's estimate, so real contract terms should always be reviewed carefully alongside this tool's projections.
Is a deferred annuity the same as a 401(k) or IRA?
No, though they share the tax-deferred growth concept. A 401(k) or IRA is a retirement account structure with specific contribution limits and tax rules set by the IRS, while a deferred annuity is an insurance product that can exist inside or outside a retirement account. Some retirement plans, particularly 403(b) plans for certain nonprofit and education employees, are specifically structured around tax-deferred annuities (TDAs) as the underlying investment vehicle.
This calculator is for educational purposes only. It is not financial advice. Always consult a qualified financial advisor before making financial decisions.
