Who is this compound interest calculator for?
Anyone comparing options in the US who wants both the math and the mindset risk called out clearly.
Behavioral lens: Present bias
Compound Interest Calculator
Clear US math plus a behavioral lens on present bias so the estimate matches real life.
Educational estimates only. Not personalized advice. Data targets 2026 US rules.
Growth inputs
$
$
%
Future value
Future value$299,160
Total contributions$130,000
Interest earned$169,160
Cost of waiting 1 year$25,870
Behavioral lens: Present bias
Watch for present bias
Your brain prefers a simple story. Present bias can hide the second number that actually changes the decision.
Waiting one year to start costs about $25,870 in future value at these assumptions.
Turn this compound interest calculator into a habit
PsyFi connects accounts and nudges so the insight becomes progress, not a one-time tab.
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How to use this calculator
- Step 1
Enter your numbers using realistic current inputs.
- Step 2
Review the highlighted result beside total cost or trade-off metrics.
- Step 3
Read the behavioral insight and pick one action you will actually keep.
The psychology behind Compound Interest Calculator
Compound Interest Calculator is designed to interrupt present bias before it becomes an expensive default. Most people do not fail at arithmetic — they fail at noticing which number their brain treats as the whole story.
Behavioral research shows that attention is scarce. When a monthly payment, refund, or social comparison pops first, other facts (total interest, match left on the table, purchasing power, runway) fade into the background. This tool puts the neglected number beside the tempting one so trade-offs are visible.
Use the output as decision hygiene. Re-run when income, rates, or goals change. Pair the estimate with a concrete next action: automate a transfer, adjust withholding, claim an employer match, or schedule a 15-minute money check-in. Insight without a habit decays quickly.
These estimates are educational. Rules, markets, and tax brackets change. Confirm details with authoritative sources linked below and with qualified professionals before you sign, contribute, or claim benefits. PsyFi exists to turn a clear moment into lasting behavior change — not to replace personalized advice.
If the result surprises you, that is useful data about present bias. Surprise is often where better plans start: rename the goal, shrink the time horizon, or add a commitment device so present-you and future-you stop negotiating from opposite sides of the table.
Authoritative sources
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FAQ
How accurate is this compound interest calculator?
It uses simplified 2026 educational assumptions. It is not tax software or a substitute for SSA/IRS calculators for filing or claiming.
Is this PsyFi calculator free?
Yes. Every PsyFi free tool runs in your browser with no signup. We pair clear math with behavioral science so you can decide without creating an account.
Does PsyFi store what I type?
No. Inputs stay on your device. Nothing you enter is sent to PsyFi servers.
Is this personalized financial advice?
No. These are educational estimates for 2026. Confirm current rules with the IRS, SSA, CFPB, or a qualified professional before acting.
Estimates for education only. Not financial, tax, mortgage, or legal advice. US federal and state rules change. Verify current figures with the IRS, SSA, or a qualified professional before acting. PsyFi tools add behavioral context; they do not replace personalized planning.