Extra Mortgage Payments: 3 Strategies That Actually Work

The baseline

$400,000 loan at 6.5% on a 30-year fixed:

• Monthly P&I: $2,528
• Total interest paid: ~$510,000 over 30 years
• Payoff: 360 months

Strategy 1 — Biweekly payments

Instead of one payment per month, pay half the amount every two weeks. That's 26 half-payments per year, or 13 full payments annually — one extra.

• Payoff: ~305 months (5 years earlier)
• Interest saved: ~$96,000

Ask your servicer if they apply biweeklies to principal without a fee. If they charge, replicate it yourself by adding 1/12 of the monthly payment to each monthly payment.

Strategy 2 — Extra $200 to principal every month

• Payoff: ~304 months
• Interest saved: ~$97,000

Nearly identical to biweekly — because that's essentially what biweekly is. This version is easier: no servicer setup, no misapplied payments.

Strategy 3 — One $10,000 lump sum in year 3

• Payoff: ~344 months (16 months earlier)
• Interest saved: ~$44,000

Timing matters. The same $10K applied in year 20 saves only ~$5,000 because most of that late-loan interest has already been paid.

Rule: an extra dollar in year 3 is worth 5× an extra dollar in year 20.

Combined attack

Extra $200/month + one$10K lump in year 3:

• Payoff: ~288 months (6 years earlier)
• Interest saved: ~$133,000

When NOT to prepay

• You have credit card debt (their APR usually beats your mortgage rate).
• You have no emergency fund (prepayment is illiquid — you can't get it back easily).
• You'd otherwise contribute to an employer 401(k) match (that's a guaranteed 100% return).

Model your own payoff

Plug your loan into the extra mortgage payment calculator to see how any combination changes your payoff date and lifetime interest.