Growing Annuity Calculator
Calculate annuity value when payments grow at a constant rate each period.
🌱 What is a Growing Annuity?
A growing annuity is a series of periodic cash flows that increase at a constant rate each period. Unlike a standard (fixed) annuity where every payment is the same, in a growing annuity the first payment is PMT, the second is PMT × (1+g), the third is PMT × (1+g)², and so on, where g is the constant growth rate. This structure better reflects real-world cash flows that tend to grow over time due to inflation, salary increases, or contractual escalation.
Growing annuities appear in many financial contexts: salary-linked pension contributions that rise with annual pay increases; inflation-adjusted retirement income streams where payouts keep pace with the cost of living; dividend discount models in stock valuation (the Gordon Growth Model is essentially the PV of a growing perpetuity); and lease agreements with annual rent escalation clauses. Understanding the present and future value of growing annuities is essential for accurate financial planning.
The key variables in a growing annuity are the first payment (PMT), the interest or discount rate (r), the payment growth rate (g), and the number of periods (n). The formulas are mathematically elegant but require that r ≠ g. When r equals g, a simpler formula applies. When g exceeds r, the growing annuity is worth more and more over time - this edge case has special implications in perpetuity valuation and the dividend discount model.
📐 Growing Annuity Formula
The growing annuity PV formula discounts each growing payment back to today. As g approaches r, the PV grows very large. For FV, the formula computes the accumulated value of all growing payments. Note: if g > r, the FV formula still works but produces a result that reflects faster-growing payments than the discount rate - this is valid and results in a larger FV than a fixed annuity would produce.