Our method
How we calculate and check examples
A calculator should make its assumptions easy to find and its result possible to check. Our tools use a shared calculation library, rather than asking an AI model to work out the arithmetic.
Money and rounding
Money calculations use decimal arithmetic or integer cents where the calculation requires it. A required contribution can round up to the next cent so a plan does not fall short. Where that creates a small excess, the final contribution is adjusted to the amount still needed. The tool shows the rounding and frequency assumptions that affect its result.
Dates and cash available
Weekly, every-two-weeks and monthly contributions are different schedules. A plan uses the number of contributions available before an expense is due. Money expected later is not available for an earlier purchase, and an existing balance is part of a goal rather than money added on top of it.
Examples are inputs, not typical spending
An article may choose a household budget or a savings target to explain a decision. Those amounts are hypothetical unless a source is explicitly identified. They are not averages, promises or a recommendation for what your household should spend. Change the inputs to fit your own situation.
Projections and outside facts
Investment projections assume the contribution timing, compounding and return shown in the tool. Actual returns vary, losses are possible, and a hypothetical rate is not guaranteed. Tax rules and other time-sensitive facts need an official source and a date checked; they are different from arithmetic calculated by a tool.
Checks and corrections
We use automated calculation tests and review worked examples before publication. Checks can miss mistakes. If a result or explanation seems wrong, send the page address and the inputs you used; please leave out account numbers or other sensitive details. Article corrections are saved as revisions so an earlier version can be restored.