Glossary and model limits
Judge the accuracy and appropriate use of YARCalc results
Understand what makes a result useful, why another calculator may disagree, and what must be checked before a real decision.
A useful model is transparent about the question it answers
SupportedYARCalc is a planning model, not a prediction. A result becomes useful when the saved household facts, balance date, assumptions, strategy, calculation, time horizon, and dollar basis match the decision being considered. More decimal places or a more complex simulation cannot compensate for the wrong question.
Projection follows one annual path. Test Market Uncertainty applies many generated economic paths to the same plan. Neither can assign certainty to future markets, inflation, law, health, lifespan, or household behavior.
Investigate a disagreement before choosing the preferred answer
Another calculator may use different timing, spending definitions, returns, inflation, taxes, account rules, longevity, or success criteria. Compare those assumptions and find the first year the results diverge before comparing final balances.
Results become stale when balances, income, spending, dates, benefits, healthcare, goals, law, or policy change. Review after a material change and use the scheduled check-in as a prompt rather than a guarantee that the plan is current.
A surprising result deserves a trace to its source. A favorable result deserves the same scrutiny; optimism is not evidence that the underlying assumptions are complete.
Check context, mechanics, and uncertainty in that order
Confirm the plan, saved plan, balance date, strategy, horizon, and dollar basis. Inspect the first changed year in Projection. Then read the relevant model boundary and current-law review date. Keep the stochastic seed locked when comparing a plan change so different random samples do not obscure its effect.
If a result still cannot be explained, use Feedback & support with the page, affected year, and the change that produced it. Keep the last trustworthy plan as your reference while the discrepancy is investigated.
Use results to identify assumptions, tradeoffs, and questions for an appropriate professional. Verify irreversible or regulated actions with current account, agency, tax, plan, insurance, and legal documents.
Accuracy does not mean certainty or completeness
Current-law basis reviewed through . Rules can change; review this guidance after a relevant law or agency update.
Selected dated income, contributions, retirement benefits, and main medical transitions use calendar-day proration. Other annual rules do not establish month-by-month cash availability. Tax calculations do not reproduce every return, and stochastic success is conditional on the model’s assumptions.
Do not treat YARCalc as an independent audit, an exact retirement date, a universally safe setting, a complete tax calculation, or a guarantee of retirement success.