Monthly P&I Calculator — Principal & Interest (2026 US & Canada)

Updated: July 20, 2026 Reviewed by WikEst Finance Team

Monthly P&I (short for Principal & Interest) is the core, fully-amortizing portion of every fixed-rate mortgage payment. Every month, the Principal slice slowly grows (paying down the balance you owe) while the Interest slice shrinks. Use our FREE Monthly P&I Calculator below, then read the official formula, the monthly P&I rate table, and US vs. Canada compounding differences.

📌 Key Takeaways — Monthly P&I (Principal & Interest)

Monthly P&I ≠ PITI: P&I = Principal + Interest only. PITI adds Taxes + Insurance + PMI (the escrow portion).
Standard formula (monthly compounding — US convention): M = P × [i(1+i)ⁿ] ÷ [(1+i)ⁿ − 1], where i = annual rate ÷ 12, n = years × 12.
Canada uses semi-annual compounding by law (OSFI rule for federally-regulated lenders): effective monthly rate = (1 + r/2)^(1/6) − 1. This produces a SLIGHTLY lower monthly P&I than US on the same stated rate.
Front-loaded interest curve: On a 2026 30-year 7.0% US fixed, Year 1 monthly P&I is ~86% interest and only ~14% principal. It takes about 21 years (252 months) before the monthly P&I becomes 50/50 principal vs. interest.
Extra P&I toward principal SAVES BIG: An extra $200/month principal payment on a 30-yr 7% $500K loan cuts ~6.5 years off the term and saves ~$165,000 in total interest.

📑 Quick Navigation — Every Monthly P&I Topic

🧮 Monthly P&I Calculator (FREE Live Tool · 2026)

Type any loan amount, annual interest rate, and loan term in years — the Monthly P&I Calculator instantly computes your monthly principal + interest payment, the total of all payments, and the total interest paid over the life of the loan. Works for conforming 30-yr fixed, 20-yr, 15-yr, 10-yr, jumbo, conforming high-balance, Canada 25-yr amortization, DSCR investor loans, and second mortgages.

🧮 FREE Tool · 2026

Monthly P&I Calculator — Principal & Interest Payment

Loan Amount (Principal)

Annual Interest Rate (APR)

Loan Term (Years)

yrs

Extra Monthly Toward Principal (Optional)

📅 Monthly P&I Payment (Required)$3,326.51Fully amortizing every month (Principal + Interest)

➕ Total Monthly With Extra Principal$3,326.51Optional extra goes 100% toward principal balance

💵 Total of All P&I Payments$1,197,54330 yrs × 12 mos × monthly P&I (or fewer years with extra pay)

🧾 Total Interest Paid (Life of Loan)$697,543Compare — 15 yr term cuts total interest by ~60%!

⏱️ New Payoff Term (If Extra $)30.0 yrsMonths saved: 0 → Interest saved: $0

What Is Principal & Interest? (Official Definition)

Google Search Console's #1 phrase for this page: "What is principal and interest". Two precise definitions — accounting and mortgage:

Principal definition (mortgage loan): The remaining unpaid balance of the money you originally BORROWED. Every time you make a monthly P&I payment, a small slice called the "principal portion" reduces this outstanding balance.
Interest definition (mortgage loan): The cost the lender CHARGES you for the privilege of borrowing their money. Calculated monthly (US) or semi-annually (Canada) on the CURRENT outstanding principal balance — not the original loan amount.

Together, Principal + Interest = Monthly P&I. The monthly P&I payment on a fully-amortizing fixed-rate loan is constant every single month (level-payment amortization). What changes EVERY month is the split between principal and interest inside that constant payment.

Principal & Interest Formula — The Exact Equation (US Monthly Compounding)

Every mortgage calculator, every LOS (loan origination system), and every underwriter uses this same principal and interest formula. Memorize it, and you can verify any monthly P&I quote in 10 seconds on a $5 calculator:

Monthly P&I = P × [ i(1+i)ⁿ ] ÷ [ (1+i)ⁿ − 1 ]

Where:
P = Initial Loan Principal (loan amount you are borrowing)
i = MONTHLY Interest Rate = Annual Percentage Rate (APR) ÷ 12
n = TOTAL Number of Monthly Payments = Loan Term in Years × 12

Principal & Interest formula breakdown for a $500,000 30-yr 7.00% US fixed (same numbers as the live calculator above):

VariablePlug In The NumbersCalculated Value P (Principal loan amount)$500,000500,000 Annual rate7.00% → i = 0.07 ÷ 12i ≈ 0.005833333 (monthly) n (total months)30 yrs × 12 = 360 months360 (1+i)ⁿ compound factor(1.005833333)^360≈ 8.1155286 Numerator: i × (1+i)ⁿ0.005833333 × 8.1155286≈ 0.0473406 Denominator: (1+i)ⁿ − 18.1155286 − 1≈ 7.1155286 Factor = Num ÷ Den0.0473406 ÷ 7.1155286≈ 0.00665302 ✅ Monthly P&I = P × Factor$500,000 × 0.00665302$3,326.51

How to Calculate Principal & Interest — 4-Step Worksheet (Printable)

Search phrase: "how to calculate principal and interest" — step-by-step for any loan, any term, any rate. Use this how to calculate principal and interest printable worksheet with a basic calculator to audit any monthly P&I Good Faith Estimate or Loan Estimate:

Step 1 — Compute i (monthly rate): Divide the annual interest rate by 100 to get decimal, then divide by 12. Example: 6.50% annual → 0.065 ÷ 12 = 0.005416667 i.
Step 2 — Compute n (total months): Multiply loan term in years × 12. Example: 15 year term × 12 = 180 months n.
Step 3 — Compute the annuity factor using the principal and interest formula: Factor = [i(1+i)ⁿ] ÷ [(1+i)ⁿ − 1]. For quick math: use a financial calculator's HP12C equivalent or the calculator at the top of this page.
Step 4 — Multiply Factor × Loan Principal: This is your MONTHLY P&I payment. Then × total months to get total-of-all-payments, then minus original principal = TOTAL INTEREST paid over life.

For Canada, replace Step 1: calculate the effective monthly rate from semi-annual compounding: i = (1 + annual_rate/2)^(1/6) − 1, then proceed with steps 2–4 identically.

Monthly P&I Table — Per $100,000 Loan Amount (By Rate & Term)

This monthly P&I table gives the exact monthly principal + interest payment PER $100,000 of loan principal. To get YOUR payment: multiply the table value × (your loan amount ÷ 100,000). Example: $400K loan at 6.875% 30 yr = $659.38 × 4 = $2,637.52 monthly P&I.

Annual Rate10-yr Mo P&I15-yr Mo P&I20-yr Mo P&I25-yr Mo P&I30-yr Mo P&I 4.00%$1,012.45$739.69$605.98$527.84$477.42 4.50%$1,036.38$764.99$632.65$555.83$506.69 5.00%$1,060.66$790.79$659.96$584.59$536.82 5.50%$1,085.26$817.08$687.89$614.09$567.79 6.00%$1,110.21$843.86$716.43$644.30$599.55 6.25%$1,122.80$857.42$730.93$659.67$615.72 6.50% (2026 avg. 30-yr)$1,135.48$871.11$745.57$675.21$632.07 6.75%$1,148.24$884.91$760.36$690.91$648.60 7.00% (2026 high range)$1,161.09$898.83$775.30$706.78$665.30 7.25%$1,174.02$912.86$790.38$722.80$682.18 7.50%$1,187.02$927.01$805.59$738.99$699.21 7.75%$1,200.11$941.28$820.95$755.33$716.41 8.00%$1,213.28$955.65$836.44$771.82$733.76

Source: Annuity formula computed to 8 decimal places per CFPB / FNMA amortization guidelines. Monthly P&I per $100K — multiply by (loan amount / 100,000). Canada loans: reduce each monthly value by about 0.10–0.15% for equivalent semi-annual compounding on the same nominal rate.

Monthly P&I By Loan Amount (2026 Conforming & Jumbo — 7.00% 30-Yr)

Search intent: users plug real numbers. This table gives instant 2026 monthly P&I for every conforming, high-balance conforming, and jumbo tier at the 2026 baseline 7.00% 30-year fixed rate.

Loan Amount TierTypical Loan Type (2026 US)Monthly P&I @ 7.00% 30 YrTotal Interest Paid Over 30 Yrs $200,000Entry-level conforming (Rural Midwest / South)$1,330.60$279,017 $300,000Standard conforming (Most suburbs)$1,995.91$418,526 $400,000Conforming (Sunbelt & Mountain)$2,661.21$558,034 $500,000Conforming national median$3,326.51$697,543 $750,000High-cost conforming$4,989.77$1,046,314 $1,000,000Conforming high-balance (2026 limit: $1,149,825)$6,653.02$1,395,086 $1,500,000Jumbo (LA, SF, NYC, Toronto)$9,979.54$2,092,636 $2,000,000Super-jumbo (Ultra-high-net-worth)$13,306.05$2,790,176

P&I vs PITI — What Mortgage Lenders Actually Qualify (The DTI Cap)

The #1 consumer mistake about monthly P&I: confusing P&I with PITI. Underwriters never qualify you on P&I alone. Here is the EXACT difference every GSC searcher needs to understand:

ComponentWhat It MeansIncluded in P&I?Included in PITI? P — PrincipalMonthly paydown of loan balance✅ YES✅ YES I — InterestLender's monthly cost of capital✅ YES✅ YES T — Property TaxesCounty / municipal tax (1–2.5% of value annually)❌ NO✅ YES I — Homeowners InsuranceHazard / fire / liability; flood if 100-yr flood zone❌ NO✅ YES PMI / MIP (Mortgage Insurance)Required if LTV > 80% (FHA MIP = 0.55–0.75% yr, Conventional PMI = 0.30–1.50%)❌ NO✅ YES (escrowed) HOA / Co-op DuesCondo, PUD, townhome mandatory fees❌ NO❌ NO (separate line in DTI)

Qualification math rule of thumb for 2026 Fannie Mae / Freddie Mac: Back-End DTI ≤ 43% (automated DU / LP approval up to 50% with compensating factors). Back-End DTI = (PITI + HOA + ALL monthly minimum debt payments) ÷ Gross Monthly Income. Example: $10K gross income → PITI + HOA + all bills ≤ $4,300/month. Monthly P&I alone in this example might only be $2,800 — don't forget the TIPs!

US vs Canada Monthly P&I — Why Canada Is Slightly Cheaper (Compounding Law)

Search Console sees cross-border shoppers typing "monthly p&i us vs canada". There is one legally-enforced difference that is NOT obvious to borrowers:

🇺🇸 🇨🇦 US vs. Canada Monthly P&I Compounding Difference

🇺🇸 United States: The Truth in Lending Act (TILA / Regulation Z) allows monthly compounding. Principal & interest formula uses i = annual_rate / 12. Most common for 30-yr fixed, 15-yr fixed, ARMs, HELOCs.
🇨🇦 Canada: OSFI Section 10 + the Interest Act (R.S.C., 1985, c. I-15) MANDATES semi-annual compounding for the posted/stated annual rate of federally-regulated residential mortgages. Effective monthly i = (1 + annual_rate/2)^(1/6) − 1. This is called the "Canadian mortgage equivalent formula" or "semi-annual to monthly conversion".

Concrete example — $500K loan, 7.00% stated rate, 25-yr amortization (Canada max) / 30-yr (US):

ScenarioEffective Monthly i UsedMonthly P&I PaymentTotal Interest Over Full Term 🇺🇸 US: 7.00%, 30-yr, monthly compound0.07 ÷ 12 = 0.005833333$3,326.51$697,543 🇨🇦 Canada: 7.00%, 25-yr, semi-annual compound(1+0.07/2)^(1/6) − 1 ≈ 0.005750040$3,495.48$548,644 Delta: Same 7.00% rateUS i is 1.45% higher monthly+Canada term is 5 yrs shorterCanada saves ~$148,899 (shorter term + better compounding)

Canada's 25-yr maximum amortization for insured (≤$1M purchase) mortgages is the primary driver of the total-interest savings, not the compounding. Compounding alone on IDENTICAL 30-yr terms at 7.00%: Canada's P&I is about $3,311 vs. US $3,327 — only ~$16/month cheaper on $500K. Shortening the amortization from 30 → 25 years is what really crushes interest expense.

Monthly P&I Amortization Split — Year 1 vs Year 10 vs Year 25 (Front-Loaded Interest Curve)

This is the single most important chart every new homeowner needs to SEE before signing. On a standard 30-year fixed mortgage, YEARS go by before you build real equity. Here is the monthly P&I split for our canonical $500,000 7.00% 30-yr example:

Month # (Milestone)Total Monthly P&IPrincipal Portion This MonthInterest Portion This Month% of Payment Going to PrincipalRemaining Balance After Payment Month 1 (Very first payment)$3,326.51$409.85$2,916.6712.3% Principal$499,590.15 Month 12 (End of Year 1)$3,326.51$437.32$2,889.1913.1% Principal$494,913.95 Month 60 (End of Year 5)$3,326.51$580.39$2,746.1217.4% Principal$470,428.16 Month 120 (End of Year 10)$3,326.51$821.10$2,505.4124.7% Principal$428,691.69 Month 180 (End of Year 15 / HALFWAY)$3,326.51$1,161.86$2,164.6534.9% Principal$367,343.62 (still owe 73.5%!) Month 252 (End of Year 21 = 50/50 Cross-over)$3,326.51$1,789.61$1,536.9053.8% Principal$249,989.45 Month 300 (End of Year 25)$3,326.51$2,502.78$823.7375.2% Principal$119,430.50 Month 360 (Final Payment!)$3,326.51$3,307.28$19.2399.4% Principal$0.00

This is why 15-yr fixed mortgages are POWERFUL: On the same $500K at 6.375% 15-yr (current 2026 spread), monthly P&I is $4,319.34 (higher), but Month 180 = balance $0. Total interest paid over 15 years = ~$277,481 — compared to ~$697,543 of interest on 30-year 7%. You save ~$420,000 of interest expense for about $1,000/month higher payment.

Extra Monthly P&I Toward Principal — Savings Calculator Scenarios

Every extra dollar of monthly payment applied to principal saves you COMPOUND interest over DECADES. Use the calculator at the top of this page (Extra Monthly field) or use these 3 pre-computed scenarios for the same $500K 7.00% 30-yr loan:

Extra Monthly $ Toward PrincipalNew Total Monthly OutlayNew Payoff TermMonths / Years SavedTotal Interest SavedROI on Extra Payments (approx.) $0 extra (Baseline)$3,326.51360 months (30.0 yrs)0 months saved$0— +$100/mo$3,426.51330 months (27.5 yrs)30 mos = 2.5 yrs$73,882Effective return = ~11.2%/yr on extra $ +$200/mo$3,526.51305 months (25.4 yrs)55 mos = 4.6 yrs$139,718~11.8%/yr +$500/mo$3,826.51249 months (20.8 yrs)111 mos = 9.25 yrs$287,646~12.6%/yr (tax-free, risk-free) +$1,000/mo$4,326.51195 months (16.25 yrs)165 mos = 13.75 yrs$438,692~13.1%/yr

Compare that ~11–13% risk-free, tax-equivalent return on extra P&I principal to: 4.5–5.25% high-yield savings, 7–9% long-term stock market (with volatility). If you are NOT maxing 401(k) employer match + Roth IRA, do those FIRST because of the INSTANT 50–100% match return. If you ARE maxing retirement accounts? Extra monthly P&I principal is a mathematically unbeatable risk-free investment in 2026's 7% rate environment.

Related Glossary Terms

Related Cross-Tool & Cross-Website

Need a more detailed PITI calculation including taxes, insurance, PMI, and HOA? Use the cross-site tool:

AllMoneyCalc — Full Mortgage PITI Calculator with Amortization Chart

FAQ — Monthly P&I Principal & Interest (Every Search Console Question)

Your monthly mortgage statement shows TWO lines: (1) Loan Amount Due / P&I = the amortizing principal + interest portion that is applied to the loan. (2) Escrow (Impound) Portion = property taxes + homeowners insurance + PMI, held in a separate trust account by the servicer and paid out on your behalf 1–2× per year. Only the P&I portion builds equity; the escrow portion is just a pass-through bill.

How to calculate principal and interest by hand: 1) Start with remaining balance × (annual_rate ÷ 12) = THIS MONTH'S INTEREST PORTION in $ 2) Subtract that interest $ from your fixed monthly P&I → THIS MONTH'S PRINCIPAL PORTION in $. 3) Subtract that principal $ from balance → NEW balance. Repeat 360 times. That's exactly how the amortization schedule is built — month by month.

YES — on a fully-amortizing fixed-rate mortgage, the P&I total payment is mathematically IDENTICAL every single month for 360 months (30 yr) or 180 months (15 yr). The ONLY thing that changes month-to-month is the internal split between principal (growing) and interest (shrinking). If your actual payment changes from year to year, that change is 100% caused by your ESCROW portion re-adjusting for higher/lower property taxes or insurance premium changes — NOT P&I.

PRINCIPAL portion of monthly P&I: NEVER deductible (it's just transferring your own money from cash to home equity). INTEREST portion of monthly P&I: WITHIN LIMITS — on your primary residence + 1 second home, you can itemize-deduct mortgage interest paid on up to $750,000 of acquisition indebtedness (per TCJA 2017, extended to 2025, current 2026 law pending renewal). For HELOC / cash-out refinance proceeds used for anything OTHER than capital improvements on the same property, interest is generally NON-deductible after 2017. Canada: no personal-residence mortgage interest deduction at all.

ABSOLUTELY NOT — for rate-and-term refinance alone. Never refinance a 3% 2021-era 30-yr into 7% 2026 just to consolidate debt or pull cash out. Instead: open a standalone 2nd mortgage / HELOC at 80% CLTV max, keep your first mortgage UNTOUCHED, and pay the 2nd off aggressively with extra monthly P&I principal. This preserves the #1 financial asset most American homeowners have: their sub-4% legacy 30-year fixed rate.

Bi-weekly P&I = pay HALF the monthly P&I every 14 days. Because there are 52 weeks/year = 26 bi-weekly payments = 13 FULL monthly equivalents (26 ÷ 2) instead of 12. So you effectively make 1 extra full month of P&I per year — applied entirely to principal. On our $500K 7% 30-yr: bi-weekly P&I schedule pays off in 309 months (25.75 yrs) instead of 360, saving ~$119,400 of total interest. It's NOT magic — it's just a forced-savings method of +1/12 payment every month.

Monthly P&I (fully amortizing) = slow forced equity building + payment never increases + loan self-liquidates at end. Interest-only (IO) = lower monthly payment during IO period (usually 10 years), but: (1) ZERO principal is paid during IO years, (2) after IO ends, payment RESets to amortize the FULL original balance over 20 years → monthly P&I JUMPS by 40–60%. Only pick IO if you are a sophisticated real estate investor redeploying the principal-difference into 12%+ yielding assets (BRRRR, cash-flowing MF), and you have a documented exit strategy to refinance or sell before the IO recast date.

Disclaimer: This content is for informational and educational purposes only and does not constitute financial, tax, mortgage, or legal advice. Monthly P&I calculations are mathematical approximations using the standard level-payment annuity formula; actual lender payoff quotes may vary by ±$0.03–$5.00/month due to rounding conventions, per-diem interest, escrow impound selection, lender-specific point buy-downs, and Canada/US compounding differences. Consult a licensed mortgage loan originator (MLO) for US residential or a licensed mortgage broker for Canadian residential for personalized Loan Estimates / commitments tailored to your credit, property type, occupancy, and income documentation. Interest deductibility rules are complex and change frequently; confirm with a CPA or enrolled agent before claiming itemized mortgage interest on Form 1040 Schedule A.