Extra Mortgage Payment vs. ETF Savings Plan: The Honest Calculator Guide 2026
What does an annual $5,000 extra mortgage payment really deliver — and what would the same money in a world ETF have done? This page is the bridge to the actual calculator: see the math in 5 scenarios, learn the levers, then jump to the interactive tool with your own numbers.
Rule of thumb: $5,000/yr × (7 % ETF − 2 % mortgage) × 20² ÷ 2 = roughly $50,000 surplus in the ETF variant. Real value depends on volatility, tax allowance and prepayment rules — the actual calculator factors all that in.
5 typical scenarios compared
| Scenario | Mortgage | ETF assumption | ETF end value | Payoff end value | Winner |
|---|---|---|---|---|---|
| $200/mo, 30 yrs, low rates | 1.5 % | 7 % nominal | ~$245,000 | ~$91,000 | ETF +154k |
| $200/mo, 30 yrs, medium rates | 3.5 % | 7 % nominal | ~$245,000 | ~$125,000 | ETF +120k |
| $200/mo, 30 yrs, high rates | 5.5 % | 7 % nominal | ~$245,000 | ~$165,000 | ETF +80k |
| $500/mo, 15 yrs, medium rates | 3.5 % | 5 % real | ~$134,000 | ~$118,000 | ETF +16k |
| $500/mo, 15 yrs, high rates | 5.5 % | 5 % real | ~$134,000 | ~$138,000 | Payoff +4k |
Assumptions: capital-gains allowance fully used, no inflation rebasing, ETF end value pre-sale tax. With shorter terms and higher rates, payoff clearly wins.
The 6 levers the calculator considers
- Mortgage rate: current market 3.5–6.5 %, existing refinances often lower.
- ETF return assumption: conservative 5 % real, medium 7 % nominal, optimistic 9 % nominal.
- Annual rate / extra payment: standard 5–10 % of loan amount, max without prepayment penalty.
- Remaining term: 5, 10, 15, 20, 30 years — leverage effect grows with term.
- Tax assumptions: capital-gains allowance, marginal rate, possibly church tax.
- Inflation: a $200k mortgage in 30 years at 2 % inflation is real $110k — that’s the debtor’s „inflation bonus“.
When does the recommendation shift?
- Mortgage rate < 3 %, long remaining term (20+ yrs).
- Capital-gains allowance not yet exhausted.
- Disciplined investor without crash panic.
- Large net worth — avoid concentration risk.
- Mortgage rate > 5 %, remaining term < 10 yrs.
- Prepayment penalty looming.
- Investor with high loss aversion.
- Retirement near — debt-freedom has comfort value.
Two practical tips
- Use the prepayment limit, rest in ETF. Most banks allow 5–10 % per year without penalty. That’s a „free“ hedge — on $200k loan use $10–$20k/year, more in ETFs.
- Raise the amortization rate instead of one-off extra payments. Instead of $10k/yr, raise from 2 % to 3 % — works monthly, flexible, no special bank approval needed.
Frequently asked questions
What about inflation in the calculation?
Important factor: at 2 % inflation over 30 years, $200k debt is real $110k. The „real“ mortgage rate is nominal rate minus inflation. At 4.5 % mortgage and 2 % inflation, real rate is 2.5 % — ETF clearly wins.
How important is volatility?
Very important — expected value is one thing, worst case another. Extra payment is certainty; ETFs can drop -40 % temporarily. Anyone forced to sell in a crash year (job loss) realizes major losses. Build emergency fund before ETF investing!
Does the calculator help with rental property?
Yes — and the effect is even stronger pro-ETF, because rental mortgage interest is deductible. At 40 % bracket, 4 % gross becomes 2.4 % net — ETF wins almost automatically.
What about forward loans?
If refinancing in 1–3 years is planned, a forward loan locks in today’s terms for the future. The calculator shows the „value“ of a forward at various rate scenarios — often money worth saving.
How accurate is the calculator?
Uses aggregated historical returns (S&P 500, MSCI World) and conservative tax assumptions. Real outcomes can deviate ±20 % — volatility is real. But the pattern (ETF beats payoff at low rates) is robust across all 30-year windows since 1970.
Is full payoff in 10 years better than the mix?
Mathematically: rarely. Psychologically: often yes. People who want to be debt-free at 60 and sleep well take 100 % payoff — and accept ~$50–$100k of foregone wealth.
Compare with your own numbers now
DCA simulator and real-return calculator — combined, you see how $5,000/year in ETFs vs. payoff performs on historical market data and crash scenarios.
- Savings plan vs. lump-sum on yfinance data
- Real return with inflation correction
- Tax calculator for individual levers