How this calculator works
The deferral phase grows an opening lump sum plus monthly contributions. The withdrawal phase uses that accumulated fund with its own return, timing, frequency, cash flow growth and reserve. Both phases share the selected compounding convention. Choose an elapsed deferral or end date. A date-based deferral includes full monthly model periods plus interest for the remaining fractional period; no contribution is inserted for that fraction. Deferral can be zero. The two tables separate accumulation from withdrawals. Tax and insurance guarantees are excluded.
Formula
Let j be the nominal annual return, m the compounding count and q payments per year. i = (1 + j/m)^(m/q) - 1, or exp(j/q) - 1 for continuous compounding. g = (1 + annual cash flow growth)^(1/q) - 1. For n payments, A = ((1+i)^n - (1+g)^n)/(i-g), with A = n(1+i)^(n-1) when i=g. Multiply A by (1+i) for beginning payments. Closing balance = opening balance x (1+i)^n + signed first payment x A. Apply the deposit formula for complete monthly periods in the deferral, compound any remaining fractional period, then use that final balance as the withdrawal opening balance.
Worked example
A $1,000 lump sum and $100 monthly deposits for one year at zero return build $2,200. With no withdrawal return, ten annual payments are $220 each. With zero deferral and a $1,000 lump sum, ten annual payments are $100 each.
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Frequently asked questions
Can the two phases use different returns?
Yes. The deferral return applies while contributions accumulate; the main annual return applies after withdrawals begin.
What happens with no deferral?
Set the deferral period to zero. The opening lump sum immediately funds the withdrawal phase and there are no deferral contributions.
Is this a deferred insurance-annuity quote?
It is a fund projection using assumed returns. Mortality pricing, guarantees, surrender charges and account tax rules depend on the contract and are excluded.