A lifetime annuity calculator has one output: the income. A fixed term annuity calculator has two, because the product pays an income for the term and then hands back a maturity value, and the two trade against each other directly. Any comparison that looks at one of them alone will pick the wrong plan.
The two outputs move in opposite directions
For a given pot and term, taking more income leaves less to return at maturity, and taking less income leaves more. A plan quoting an attractive income may simply be returning a smaller sum at the end, and a plan with a large maturity value may be paying very little in the meantime. Neither is better in itself. The only way to compare two quotations is to hold one of the two figures constant and compare the other, which is what a calculator that shows both makes possible.
Term length is an input, not a detail
Changing the term changes both outputs substantially. A shorter term generally means a larger maturity value and a smaller income, and it brings the decision point closer, which matters if you are trying to bridge to a known event such as a state pension starting. Running the same pot over five, ten and fifteen years is the most useful thing the calculator does, because it shows the shape of the trade rather than a single answer to a question you may not have framed correctly.
What the maturity value is not
It is a contractual amount, not an investment return, and it is usually fixed at outset. That means it does not grow with markets and it is not protected against inflation over the term, so the same nominal sum will buy less at the end than it would today. Comparing a maturity value in fifteen years with a pot today, without any adjustment, overstates what the arrangement preserves. The calculator will not usually make this adjustment for you.
Where the real numbers come from
Calculator outputs are indicative. An actual quotation depends on the provider, the date, your health disclosure where relevant and the exact shape chosen, and it has a short shelf life because pricing moves with yields. This site publishes no rates, arranges nothing and recommends no provider. Where you want quotations and advice on your own circumstances, the enquiry goes to a firm authorised to give them.
Questions people ask about fixed term annuity calculator
Why does a fixed term calculator show two figures?
Because the product has two outputs: the guaranteed income during the term and the maturity value at the end. They trade directly against each other, so comparing plans on income alone or on maturity value alone will select the wrong one.
How does term length change the result?
Substantially and in both outputs. A shorter term generally produces a larger maturity value and a smaller income, and it brings the next decision forward. Running several terms on the same pot is the clearest way to see the trade.
Is the maturity value guaranteed?
On most plans it is contractually fixed at outset, so it does not depend on investment performance. It is a nominal amount, which means inflation over the term reduces what it will buy even though the figure itself does not change.
Is the calculator result a quotation?
No. It is an estimate on assumptions. A real quotation reflects a provider, a date, the exact shape chosen and any health disclosure, and it reprices as yields move, so it has a short shelf life.