Free Investment Calculators — Compound Interest, Retirement & More

Investing basics every contractor should know

• 01

  Compound interest punishes delay more than most people realize. $500/month invested at 7% for 30 years grows to $567,000. Wait 10 years to start and that same $500/month for 20 years produces only $247,000 — less than half — despite investing for only 10 fewer years. Time in the market is the single most powerful variable, and it cannot be bought back.

• 02

  The Solo 401k is the most powerful retirement account available to self-employed workers. You can contribute up to $23,000 as the employee, plus 25% of net self-employment income as the employer — up to $69,000 combined in 2024. That's nearly 10× the Roth IRA limit and gives you a tool W-2 employees can't access.

• 03

  Fees compound against you just as returns compound for you. A 1% annual expense ratio on a $200,000 portfolio costs $2,000 in year one. But after 20 years of compounding, that same 1% fee has consumed over $120,000 in potential growth. Index funds with 0.03–0.20% expense ratios are the mathematical choice for most long-term investors.

• 04

  The Roth vs Traditional decision depends on your current vs future tax rate — not just your income. Contractors who expect to stay in a high bracket in retirement (or who want flexibility to manage AGI year-to-year) often benefit from Roth contributions now. Those in a low-income year — landing a big contract later — may prefer Traditional to defer taxes at a higher future rate. The break-even analysis shows exactly where the lines cross.