Can I use this to decide between two specific funds or portfolios?

You can approximate the difference by assigning each case an expected average annual return based on its risk profile. However, this tool does not model volatility, fees, or specific holdings, so it should complement, not replace, more detailed fund comparisons.

Does this calculator include taxes or account for inflation?

No. All values are in nominal (pre-tax) dollars. To factor in taxes, you could lower the assumed return for taxable accounts. To consider inflation, you can compare results using real (inflation-adjusted) return assumptions instead of nominal ones.

What if my contributions change over time?

This version assumes constant monthly contributions. To model changing contributions, you can break the projection into phases (for example, 10 years at one contribution level and 10 years at another) and run separate calculations.

Is the higher-return case always better?

Not necessarily. Higher returns usually come with higher risk and greater volatility. This calculator shows the potential difference in average outcomes, but it does not capture risk. Your comfort with risk and your time horizon should guide which scenario is appropriate.

Can I use this for short-term goals?

Yes, but be conservative with return assumptions for short horizons. For goals under five years, many advisors recommend lower-risk, lower-return vehicles, and the value of compounding is less dramatic than over decades.

finance calculator

Investment / Savings Comparison

Compare two side-by-side saving or investing scenarios with different starting balances, monthly contributions, and return assumptions.

Results

Case A future value: $231,020
Case A contributions: $120,000
Case A growth: $111,020
Case B future value: $183,387
Case B contributions: $120,000
Case B growth: $63,387
Difference (A - B): $47,633

Overview

Should you put extra money into one account or another? How much difference does a slightly higher return or contribution rate actually make over time? This investment / savings comparison calculator lets you set up two side-by-side scenarios—each with its own starting balance, monthly contribution, and annual return—so you can see how they grow over time and how big the gap becomes.

How to use this calculator

Enter the starting balance, monthly contribution, and annual return for Case A (for example, a more aggressive investment mix or a tax-advantaged account).
Enter the starting balance, monthly contribution, and annual return for Case B (for example, a conservative option, a taxable account, or a different savings strategy).
Choose how many years you want to project. This might line up with a specific goal, such as retirement, a down payment, or a child’s college start date.
The calculator compounds both cases monthly for the chosen number of years, tracking contributions and growth separately.
Review future value, total contributions, and growth for each case, as well as the dollar difference between Case A and Case B.

Inputs explained

Case A starting balance: The amount you already have saved or invested in Case A at the start of the projection. Set to 0 if you’re modeling a brand-new account.
Case A monthly contribution: The fixed amount you plan to add to Case A each month. This could be a payroll deduction, an automatic transfer, or a manual monthly deposit.
Case A annual return (%): Your assumed average annual return for Case A, expressed as a percentage. The calculator converts this to a monthly rate for compounding. Use conservative estimates for long-term planning.
Case B starting balance: The initial amount in Case B. This might represent an existing account with a different risk level, provider, or tax treatment.
Case B monthly contribution: The monthly contribution planned for Case B. Use 0 if you’re modeling a lump sum with no ongoing contributions.
Case B annual return (%): The assumed average annual return for Case B. For example, you might use a lower rate for a conservative or guaranteed option and a higher rate for a growth-oriented portfolio.
Years to project: The number of years over which you want to simulate growth and contributions. Longer horizons highlight the power of compounding and small differences in return or contributions.

Outputs explained

Case A future value: The projected account value for Case A at the end of the chosen time period, combining the starting balance, all monthly contributions, and compounded growth.
Case A contributions: The total amount of money you will have put into Case A over the projection (starting balance is not included in contributions). This helps you see how much of the future value comes from your own deposits.
Case A growth: The portion of Case A’s future value attributable to growth (future value minus contributions). This illustrates how much compounding has added on top of what you contributed.
Case B future value: The projected account value for Case B at the end of the period, calculated using its starting balance, monthly contributions, and return rate.
Case B contributions: The total contributions made into Case B over the projection period. Comparing this to Case A’s contributions helps show whether differences in balance come from contributions, returns, or both.
Case B growth: The amount of growth in Case B, equal to future value minus contributions. This helps you evaluate how effectively Case B’s return assumptions compound over time.
Difference (A - B): The difference between Case A and Case B future values. A positive number means Case A ends higher than Case B; a negative number means Case B ends higher than Case A.

How it works

You define Case A and Case B, each with a starting balance, a fixed monthly contribution, and an assumed average annual return. The calculator compounds both cases monthly using their respective return assumptions.

Each month, we apply a monthly growth rate to the current balance, then add that month’s contribution for each case. Over the projected number of years, this simulates a simple “contribute and grow” pattern for both scenarios.

At the end of the projection period, we compute the future value for each case, the total contributions made, and the amount of growth (future value minus contributions) for each.

We then calculate the difference between Case A and Case B future values (A − B) to show how much more (or less) you’d have by choosing one scenario over the other.

This is a deterministic, simplified model: returns are constant, contributions don’t vary, and we ignore fees, taxes, and volatility to highlight the impact of contribution rates and average returns.

Formula

For each case (A and B):\nMonthly rate r = Annual return_decimal ÷ 12\nMonths N = Years × 12\nWe iterate monthly:\nBalance_next = (Balance_current × (1 + r)) + Monthly contribution\nAfter N months:\nFuture value = Final balance\nTotal contributions = Monthly contribution × N\nGrowth = Future value − Total contributions\nDifference (A − B) = Future value_A − Future value_B

When to use it

Comparing a higher-risk, higher-return investment portfolio (Case A) to a conservative savings or bond-heavy portfolio (Case B) to see how the gap evolves over time.
Evaluating whether increasing monthly contributions (Case A) or chasing a higher expected return (Case B) has a bigger impact on your long-term wealth.
Testing scenarios like investing in a tax-advantaged account vs a taxable account using different assumed after-tax return rates.
Comparing two different savings goals (for example, retirement vs a home down payment) to understand how contributions and returns drive each goal’s projected balance.
Demonstrating the impact of starting earlier vs starting later by giving one case a head start in years, contributions, or starting balance.

Tips & cautions

Use realistic, long-term return assumptions based on diversified portfolios rather than recent short-term market performance. Over-optimistic returns can dramatically inflate future values.
If you’re modeling taxable investments vs tax-advantaged accounts (like IRAs or 401(k)s), lower the assumed return for taxable accounts to approximate the drag from taxes, or run separate tax calculations.
Consider running multiple scenarios with the same contributions but different returns, and then with the same returns but different contributions, to see which lever you can realistically pull more effectively.
Remember that higher-return scenarios usually come with higher volatility and risk. The calculator shows averages; real-world paths can be bumpier.
Revisit your projections periodically as your actual contributions and returns become known; adjust inputs to keep your plan grounded in current realities.
Assumes constant monthly contributions and constant average returns; real investments experience volatility, and contributions may change over time.
Does not incorporate fees, taxes, inflation, or required minimum distributions, all of which can materially affect real-world outcomes.
Uses a simplified compounding model and does not simulate specific asset allocations, market cycles, or sequence-of-returns risk.
Treats both cases as independent accounts without modeling interactions like rebalancing, withdrawals, or moving funds between them.

Worked examples

Example 1: Higher return vs lower return, same contributions

Case A: Starting balance $0, monthly $500, annual return 6%, years = 20.
Case B: Starting balance $0, monthly $500, annual return 4%, years = 20.
Total contributions for each ≈ $500 × 12 × 20 = $120,000.
Future value for Case A is significantly higher due to the 6% return; Case B grows less at 4%. The difference (A − B) shows the cost of the lower return over 20 years.

Example 2: Higher contributions vs higher return

Case A: Starting $0, monthly $700, annual return 6%, years = 20.
Case B: Starting $0, monthly $500, annual return 8%, years = 20.
Comparing future values and growth shows whether contributing more at a modest return beats contributing less at a higher assumed return under these assumptions.

Example 3: Starting earlier vs starting later

Case A: Starting balance $20,000, monthly $500, annual return 6%, years = 20.
Case B: Starting balance $0, monthly $500, annual return 6%, years = 20.
Case A’s head start results in a larger future value; the difference quantifies the effect of that early lump sum and extra time in the market.

Deep dive

Use this investment vs savings comparison calculator to model two side-by-side scenarios with different starting balances, monthly contributions, and annual returns. See each case’s future value, total contributions, and growth, plus the dollar difference between them.

Ideal for comparing aggressive vs conservative portfolios, taxable vs tax-advantaged accounts, or alternative savings strategies so you can see how small changes in contributions or return assumptions compound over time.

FAQs

Can I use this to decide between two specific funds or portfolios?: You can approximate the difference by assigning each case an expected average annual return based on its risk profile. However, this tool does not model volatility, fees, or specific holdings, so it should complement, not replace, more detailed fund comparisons.
Does this calculator include taxes or account for inflation?: No. All values are in nominal (pre-tax) dollars. To factor in taxes, you could lower the assumed return for taxable accounts. To consider inflation, you can compare results using real (inflation-adjusted) return assumptions instead of nominal ones.
What if my contributions change over time?: This version assumes constant monthly contributions. To model changing contributions, you can break the projection into phases (for example, 10 years at one contribution level and 10 years at another) and run separate calculations.
Is the higher-return case always better?: Not necessarily. Higher returns usually come with higher risk and greater volatility. This calculator shows the potential difference in average outcomes, but it does not capture risk. Your comfort with risk and your time horizon should guide which scenario is appropriate.
Can I use this for short-term goals?: Yes, but be conservative with return assumptions for short horizons. For goals under five years, many advisors recommend lower-risk, lower-return vehicles, and the value of compounding is less dramatic than over decades.

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This investment / savings comparison calculator provides simplified projections based on user-entered starting balances, contributions, and constant average annual returns. It does not model market volatility, fees, taxes, inflation, or specific investment products and is not financial, tax, or investment advice. Actual results will vary. Consult a qualified financial professional before relying on projections for major financial decisions.