HELOC Amortization Calculator
Generate a complete month-by-month payment schedule across your entire HELOC lifecycle — draw period and repayment period. See exactly how much is interest, how much reduces your balance, and when your HELOC reaches $0. Free, instant, no signup required.
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Full amortization table
Every payment · draw & repayment period
Staged draw support
Lump-sum vs monthly draws compared
Extra payment accelerator
See how extra principal shortens payoff
Example calculation
Live results
Your scenario
HELOC amount drawn
Interest rate (APR)
Draw strategy
Draw period payment
$353/mo
Interest-only · 120 months
Repayment period payment
$434/mo
P+I amortizing · 240 months
Total lifetime interest
$96,477
Over 30 years · $50,000 at 8.25%
HELOC Amortization Calculator — Full Payment Schedule
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Your HELOC details
Draw period
$50,000
$
8.25%
%
Repayment period
$0
$
Your amortization results
Draw period payment
$353/mo
Interest-only · 120 months
Repayment payment
$434/mo
P+I · 240 months
Draw period interest
$42,350
10 yr draw · IO only
Repayment interest
$54,127
20 yr repayment
Total lifetime interest
$96,477
Over 30 years · $50,000 at 8.25%
⚡ Payment shock at repayment start
Draw period IO
Repayment P+I
+23% jump when repayment starts
| Month | Phase | Payment | Interest | Principal | Balance |
|---|---|---|---|---|---|
| Adjust inputs to generate your schedule | |||||
Outstanding balance over time
Draw period
Repayment period
Rate used: 8.25%
· Check today’s rates →
Understanding HELOC amortization
What is HELOC amortization?
A HELOC has two distinct phases with very different payment structures. The draw period is not amortizing — only the repayment period is.
Draw period
Phase 1 — IO only
During the draw period payments are interest-only. No amortization occurs at the minimum payment — your balance stays unchanged.
Typical length5–10 years
Payment typeInterest-only
Principal balanceUnchanged at minimum
FormulaBalance × (Rate÷12)
Example: $50K @ 8.25%$353/mo
Repayment period
Phase 2 — P+I
The outstanding balance is fully amortized over the repayment period. Payments include principal + interest — automatically higher.
Typical length10–20 years
Payment typePrincipal + interest
Principal balanceReduces monthly
Example: $50K/8.25%/20yr$434/mo
✓ HELOC — two-phase
Phase 1IO only — no amortization
Phase 2Fully amortizing P+I
Phase 2 paymentHigher (+20–30%)
Balance during drawUnchanged at minimum
≈ Home equity loan
From day 1Fully amortizing P+I
PaymentFixed — never changes
Payment shock✓ None
BalanceReduces from month 1
Draw period minimum = 100% interest
$0 reduces your principal. After 10 years of minimums, you still owe the full drawn amount.
Amortization starts automatically at repayment
On day 1, your full outstanding balance begins amortizing. Payment jumps permanently.
Extra principal during draw = powerful
Reduces the balance entering repayment — permanently lowering every future P+I payment.
Real numbers — $50,000 at 8.25%
Draw period vs repayment — how they differ
The same $50,000 HELOC at 8.25% produces completely different payment structures. Key milestones side by side.
Key milestones — $50K · 8.25% · 10+20yr
| Month | Phase | Payment | Interest | Principal | Balance |
|---|---|---|---|---|---|
| Mo 1 | Draw | $353 | $353 | $0 | $50,000 |
| Mo 60 (Yr 5) | Draw | $353 | $353 | $0 | $50,000 |
| Mo 120 (Yr 10) | Draw | $353 | $353 | $0 | $50,000 |
| ⎯⎯ DRAW PERIOD ENDS — REPAYMENT BEGINS ⎯⎯ | |||||
| Mo 121 (Yr 11) | Repay | $434 | $353 | $81 | $49,919 |
| Mo 181 (Yr 16) | Repay | $434 | $286 | $148 | $40,312 |
| Mo 241 (Yr 21) | Repay | $434 | $192 | $242 | $26,966 |
| Mo 301 (Yr 26) | Repay | $434 | $72 | $362 | $9,847 |
| Mo 360 (Yr 30) | Repay | $434 | $3 | $431 | $0 |
Totals for this scenario
Draw interest
$42,350
Repay interest
$54,127
Total interest
$96,477
Draw period — 10 years
Phase 1
$353/mo
Interest-only · 120 months
100%
Goes to interest
0%
Reduces principal
Monthly IO payment$353
Annual interest$4,235
10-yr total interest$42,350
Balance after 10 yrs$50,000 (unchanged)
Repayment period — 20 years
Phase 2
$434/mo
Principal + interest · 240 months
81%
Interest (mo 121)
99%
Principal (mo 360)
Monthly P+I$434
Mo 121: $353 int / $81 prin—
Mo 360: $3 int / $431 prin—
20-yr total interest$54,127
⚡ Payment shock — what changes at repayment
Draw period$353/mo (IO)
Repayment$434/mo (P+I)
Monthly increase+$81/mo (+23%)
How to reduce itPay extra principal during draw
Smarter borrowing strategy
How staged draws & extra payments change your schedule
Two strategies reduce total interest significantly — staging your draws and making extra principal payments. Real numbers for a $100,000 HELOC at 8.25%.
Lump sum vs staged — $100K · 8.25% · 10-yr draw
| Metric | Lump sum | Staged ($10K/mo) |
|---|---|---|
| Balance at month 1 | $100,000 | $10,000 |
| Balance at month 6 | $100,000 | $60,000 |
| Balance at month 10 | $100,000 | $100,000 |
| Month 1 IO payment | $706/mo | $71/mo |
| Draw period interest | $84,700 | $46,585 |
| Repayment payment | $868/mo | $868/mo |
| Repayment interest | $108,314 | $108,314 |
| Draw period savings | — | $38,115 less |
💡 The staged draw rule
Draw only what each project phase needs right now. Every dollar undrawn costs $0 in interest.
Extra payment impact — $50K HELOC
8.25% · 10+20yr
| Extra/mo | Repay balance | P+I/mo | Repay int. | Saved |
|---|---|---|---|---|
| $0 (min) | $50,000 | $434 | $54,127 | — |
| +$100 | $38,000 | $330 | $41,137 | $12,990 |
| +$200 | $26,000 | $226 | $28,148 | $25,979 |
| +$350 | $8,000 | $69 | $8,663 | $45,464 |
| +$500 | $0 | $0 | $0 | $54,127 |
Optimal draw & paydown strategy
1
Draw per invoice, not all at once
Draw only what each phase needs now. Never draw the full limit until work begins.
2
Pay extra principal during draw period
Every extra dollar reduces the balance entering repayment — permanently lowering your P+I.
3
Set a repayment target before drawing
Model your repayment P+I before the first draw. If it creates budget stress, draw less or plan extra payments.
5 questions answered
HELOC amortization FAQ
The most common questions about HELOC amortization, draw period payments, and repayment schedules — answered with real numbers.
No — the draw period is interest-only and does not amortize. Only the repayment period is fully amortizing. During the draw period your minimum payment covers interest only; your balance stays unchanged. This is the key difference from a home equity loan, which amortizes from payment #1.
The HELOC converts from interest-only to fully amortizing P+I automatically on the first day of the repayment period. Your payment increases — typically 20–30% — and remains at that level for the entire repayment period. You cannot avoid this transition; the only way to reduce the repayment payment is to reduce your balance before it begins.
Yes — and it’s the most impactful thing you can do. Every dollar of principal paid during the draw period reduces the balance entering repayment, permanently lowering every future P+I payment. Use the “Extra monthly payment” slider in the calculator above to see exactly how much you save in total interest and by how much your repayment payment drops.
Your balance on day 1 of the repayment period will equal your full drawn amount — unchanged. You will have paid interest for 10 years and still owe every dollar you borrowed. On $50,000 at 8.25% for 10 years, that’s $42,350 in interest paid with $0 in principal reduction. The full $50,000 then amortizes over the repayment period.
A 30-year mortgage amortizes from payment #1 — every payment includes some principal, and your balance declines from the start. A HELOC draw period is interest-only with no amortization. Only the repayment period amortizes, typically over a shorter term (10–20 years), which is why the payment shock at repayment start is significant. The full amortization schedule above shows both phases in a single view.