Savings & Investment Calculators: Which One Do You Need?
These six tools split into two directions: project forward from what you're already saving, or work backward from a target you want to hit. Here's how to tell which direction your question is actually asking.
Quick picker
- "If I save $X a month, what will I have?" — Compound Interest Calculator for a general fund, or Retirement Savings Calculator if it's specifically for retirement and you want an employer match counted in.
- "How much do I need to save monthly to hit a target?" — Savings Goal Calculator. This is the backward version of the two above.
- Saving for a specific kid's college fund? — College Savings Calculator, which projects against a future cost target rather than a fixed dollar goal you pick yourself.
- "Is my fund's expense ratio actually a big deal?" — Investment Fee Calculator. Almost always the answer is closer to "yes" than people expect.
- "What's this future dollar amount actually worth?" — Inflation Calculator, run on any of the projected totals above.
Worked scenario: a 25-year retirement projection
- Run the Retirement Savings Calculator with your current balance, monthly contribution, and employer match to get a projected balance at retirement age.
- Compare two funds for that account in the Investment Fee Calculator — a 0.05% index fund against a 0.75% actively-managed fund — to see the real dollar gap in fees paid over 25 years, not just the 0.70 percentage-point difference on paper.
- Take the projected retirement balance and run it through the Inflation Calculator at a long-run average inflation rate to see what that balance is actually worth in today's spending power — the number that matters for deciding if you're on track, not the raw future figure.
All savings & investing tools
- Compound Interest Calculator Watch a balance grow with compound interest and regular contributions, year by year.
- Savings Goal Calculator Work out the monthly deposit that gets you to a savings target by your deadline.
- Inflation Calculator See what today's money will be worth later — or what past money equals now — at any inflation rate.
- Retirement Savings Calculator Project your retirement balance from your current savings, monthly contributions, and employer match.
- Investment Fee Calculator See exactly how much an expense ratio quietly costs you in lost growth over the years.
- College Savings Calculator Project a college fund from today's balance and monthly contributions against a future cost target.
Frequently asked questions
What's the actual difference between the Compound Interest Calculator and the Retirement Savings Calculator?
The Compound Interest Calculator is the general-purpose version — any lump sum, any contribution schedule, any time horizon, no assumptions about what the money is for. The Retirement Savings Calculator is the same underlying math specialized for retirement specifically: it adds an employer-match field, since that's free money most 401(k) savers should be accounting for and a generic compound-interest tool has no field for. Use retirement-specific for retirement, general for everything else — a house down payment fund, a wedding fund, any other savings goal.
I have a target amount and a deadline — which tool tells me what to save each month?
The Savings Goal Calculator, specifically. It's the reverse of the Compound Interest Calculator: instead of "here's what I'm saving, what will I have," it solves "here's what I need and when, what must I save monthly to get there." Feed it your target, deadline, current balance, and an assumed rate of return.
Why does the Investment Fee Calculator matter if fees are usually under 1%?
Because that 1% compounds against you for decades, the same way contributions compound for you. A 1% expense ratio on a retirement account isn't 1% of your final balance lost — over 30 years it's commonly 20-25% of what the account would otherwise be worth, since the fee is also charged on all the growth that fee-drag prevented from happening. The calculator shows that real number instead of leaving it as an abstract-sounding percentage.
Should I use the Inflation Calculator before or after running a retirement projection?
Both, for different questions. Run the Retirement Savings Calculator first to see your projected balance in future dollars. Then run the Inflation Calculator on that same number to see what it's actually worth in today's purchasing power — a $2 million balance in 30 years sounds large, but the Inflation Calculator is what tells you honestly whether it still is once prices have moved.