How much will $20,000 be worth in 20 years?

How quickly $20,000 grows

At 7%, $20,000 doubles during year 11. From then on, more than half of the balance is growth, and by the end of year 20 the balance is 3.87 times the original amount. The rate matters a lot here: the money doubles in year 8 at 10% and in year 18 at 4%.

Growth also speeds up over time. In year 1 the investment earns $1,400 at 7%. In year 20 it earns $5,063, because each year's return is calculated on a larger balance.

What if you change the plan?

Each row changes one thing and keeps everything else the same, at the 7% example rate. The comparison is with $20,000 invested for 20 years, which ends at $77,394.

Waiting 5 years to invest the same $20,000 leaves the final balance $22,213 lower, even though you put in exactly the same amount. The last 5 years add the most because they are earned on the largest balance. A return that is one point lower leaves you with $13,251 less after 20 years, which is roughly what a 1% annual fee would cost.

Working backwards: to have $100,000 in 20 years at 7% without adding anything, you would need to invest about $25,842 today.

When would the balance reach $100,000?

The table shows the year in which the balance first reaches each amount, assuming nothing is added or withdrawn. Years in bold fall within this page's 20-year period.

How this is calculated

For a single investment with nothing added, the rate is applied once a year to the whole balance:

Balance = Principal × (1 + annual rate)^years

With this page's numbers at 7%:

Balance = 20,000 × 1.07²⁰ ≈ 20,000 × 3.8697 ≈ $77,394

Growth is the balance minus the original $20,000: $57,394. Every other row in the rate table uses the same formula with a different annual rate. The compound interest calculator page explains the formulas in more detail, including monthly contributions.