How does a mortgage calculator work?

A mortgage calculator estimates your monthly payment, total interest and amortization schedule from three inputs: loan amount, annual interest rate and term in years. It applies the French amortization formula (the global standard) and returns a fixed monthly installment plus a month-by-month breakdown. It is the best tool to compare scenarios before signing — change one input and see the impact instantly. Simúlalo's mortgage calculator is free, no signup, and works for loans from any bank in Mexico (BBVA, Banorte, Santander), Spain (BBVA, Santander, ING), Colombia, and the US.

How much down payment do I need for a mortgage?

The standard down payment in 2026 is between 10% and 30% of the property price, depending on country and program. Spain: 20% minimum at most banks (LTV cap of 80%); ICO Joven program goes lower for under-35s. Mexico: private banks ask 10-20%; INFONAVIT and FOVISSSTE allow much lower. US: 20% conventional, 3.5% FHA, 0% VA for veterans. Colombia: 30% for bank loans. Larger down payments reduce the monthly payment and unlock better rates — going from 10% to 30% can lower your rate by 0.5-1.0pp.

What is the difference between nominal interest rate and APR (TAE/CAT)?

The nominal rate (TIN in Spain, tasa nominal in Mexico, interest rate in the US) is just the cost of the borrowed money. The APR (TAE in Spain, CAT in Mexico) includes the nominal rate plus opening commission, mandatory insurance, linked products and fees — it is the real number to compare across lenders. APR is always higher than the nominal rate. A loan with 3.5% nominal and 4.2% APR is more expensive than one with 3.7% nominal and 3.9% APR. Regulators require lenders to disclose APR for this exact reason.

How much is the monthly payment on a $200,000 mortgage at 30 years?

For a $200,000 mortgage at 30 years with a fixed 6.5% rate (typical 2026 US market), the monthly payment is approximately $1,264 and you pay $255,069 in total ($255,069 - $200,000 = $55,069 in interest beyond what you'd expect with simple math, because the interest compounds). At 7.0% the payment rises to $1,331. At 5.5% it drops to $1,136. Use Simúlalo's mortgage calculator (/simulador/finanzas/calculadora-hipoteca) to plug in your exact numbers — currency, rate, term — and see the full breakdown.

Is a fixed-rate or variable-rate mortgage better in 2026?

For most buyers in 2026, fixed-rate is the safer bet. Reason: it protects you from central bank rate hikes (the Fed, ECB, Banxico, BCE all moved rates up 4-7 percentage points between 2022-2024) and gives you predictable payments for 20-30 years. Variable rate is only attractive if you expect rates to FALL during the loan's life and you can absorb increases if you're wrong. Historically variable mortgages backfired in tightening cycles — Spanish variable mortgages tied to EURIBOR saw monthly payments rise 50-80% between 2022 and 2024.

What mortgage rates do banks offer right now?

2026 mortgage rates by market: US conventional 30-year fixed 6.5-7.0%, FHA 6.2-6.7%; Spain fixed 25-year 3.0-4.0% (BBVA 3.05%, Santander 3.10%, ING 3.20%); Mexico bank fixed 9.5-12.5% (BBVA 9.85%, Banorte 9.95%, Santander 9.90%); Mexico INFONAVIT 4-12% by salary band; Colombia bank UVR + 7-9%. Always compare APR, not just the headline rate. Rates update quarterly with central bank moves. Simúlalo's mortgage calculator works across all these markets — pick your currency and apply the rate from your bank's offer.

What documents do I need to apply for a mortgage?

Standard mortgage documentation: government ID, tax ID number, proof of income for the last 3-6 months (paystubs if employed, tax returns if self-employed), proof of address, bank statements for the last 3-6 months, property appraisal (paid by the buyer, $400-1,500), credit authorization, and proof of down payment funds. Spain requires the FEIN (European Standardized Information Sheet) from the bank with a 10-day cooling-off period. Mexico requires CURP, RFC, and SAT compliance certificate. Approval typically takes 15-45 business days from full submission.

Should I take a 15, 20, or 30-year mortgage term?

Depends on the trade-off between monthly payment and total interest. 15 years means higher payments but far less total interest; 30 years means lower payments but interest can be 70-100% of the loan amount. Example: $200,000 at 6.5% — at 15 years monthly is $1,742 and total interest is $113,665; at 30 years monthly is $1,264 and total interest is $255,069. The 28%/36% rule says your housing cost should not exceed 28% of gross income and total debt 36%. If you can afford the 15-year payment without strain, it usually saves more than $100,000 in interest.

Can I make extra principal payments on my mortgage?

Yes, in most modern mortgages. In Spain, Ley 5/2019 caps early-repayment penalties at 2% of the repaid amount during the first 10 years for fixed-rate loans, then 1.5% beyond that. In Mexico, CONDUSEF requires disclosure but does not cap the rate — read your contract. In the US, most conventional mortgages have no prepayment penalty. When making extra payments, you can choose to (a) reduce the term (keep paying the same monthly amount but finish earlier — saves the most interest) or (b) reduce the monthly payment (lower payments but same end date). Reducing the term is almost always more efficient.

What other costs should I budget beyond the mortgage payment?

Closing costs add 7-10% of the property price on top of your down payment — and they are not in the monthly mortgage. Typical line items: property appraisal ($400-1,500), notary and registration fees (3-7% of property value), property transfer tax (varies by jurisdiction: 2-5% in Mexico, 6-10% in Spain, 0.5-2% in the US), bank origination commission (0.5-1.5% of the loan), mandatory insurance (life + homeowners, 0.3-0.5% annually), and moving costs. On a $300,000 home this can mean $21,000-30,000 in cash beyond your down payment. Plan for it before house hunting.

Mortgage Calculator 2026: Monthly Payment & Interest Rate

Variables

Loan amount

Principal borrowed (excluding down payment). Currency follows the active selector (USD, EUR, MXN, COP, ARS, CLP).

Annual rate

Fixed annual interest rate. Typical: 6.5% US conventional 30-yr, 3% Spain fixed, 10.5% Mexico bank.

Term

Years to pay off the loan. Common terms: 10, 15, 20, 25 or 30 years.

Monthly income

Optional. If you add it, we compute the payment-to-income (DTI) ratio banks look at when approving.

Practical example

Loan: $400,000 USD over 30 years at 6.5% fixed.

Monthly rate: 6.5 ÷ 12 ÷ 100 = 0.005417.

Number of payments: 30 × 12 = 360 months.

Monthly payment ≈ $2,528 USD.

Total paid: $2,528 × 360 = $910,000 USD.

Total interest: $910,000 − $400,000 = $510,000 USD — you pay 128% extra in interest over the principal.

Interpretation

If total interest exceeds the principal, consider shortening the term or negotiating the rate — long-term loans transfer enormous wealth to the lender.

Lenders typically reject loans where the payment exceeds 35% of monthly net income. Below 25% is comfortable.

Cutting the term from 30 to 15 years raises the payment ~30% but slashes total interest by ~60%.

Comparing two mortgages is more than comparing rates: check APR (or CAT/TAE in Latin America/Spain) which includes fees.

Assumptions and limitations

Fixed rate over the entire term. Adjustable-rate (ARM) or hybrid mortgages will have payments that change after the reset date.

Excludes origination fees, closing costs, taxes, and insurance (life, hazard) — budget those separately.

Excludes prepayments. Any extra payment to principal reduces total interest but is not modeled here.

The result is indicative. The final payment depends on the exact rate the lender approves after evaluating your profile.

When to use this calculator

Before visiting a lender, so you walk in with a realistic monthly payment range and don't accept the first rate offered.

To compare offers from multiple lenders holding loan amount and term constant — see which offer leaves less total interest.

When deciding between 15, 20 or 30 years. Seeing total interest per scenario typically changes the decision.

To validate the payment fits your income before falling in love with a property outside your real capacity.

To understand the effect of a larger down payment: lowering the loan amount cuts payment and interest non-linearly.

If you plan to make principal prepayments, simulate the shorter term (without extras) first to see if the base payment is workable.

Common mistakes

Looking only at the monthly payment, not total interest. A comfy 30-year payment can cost double the total of a tighter 15-year payment.

Forgetting closing costs: title, recording, transfer tax, origination fee, mandatory insurance. These can add 2-5% of the loan in the US, 8-12% in Mexico.

Not checking APR. Lenders compete on nominal rate but APR — which includes fees — can tell a different story.

Assuming future income will rise to justify a high payment today. Lenders assess your current situation; if income drops the payment doesn't.

Defaulting to the maximum term out of habit. In most cases, a 15-20 year term plus periodic prepayments comes out far better.

Industry use cases

First-time buyer (US)

$350,000 home with 20% down ($70,000). Loan of $280,000 over 30 years at 6.5% fixed: monthly payment ~$1,770. Need net income above $5,050/mo for the payment to stay at 35% DTI (lender soft cap).

Investor — rental property

$220,000 condo with 25% down. Loan of $165,000 over 15 years at 7%: payment ~$1,484/mo. If expected rent is $1,800-2,000, post-maintenance net cash flow is thin — raise down payment or shift markets.

Spain — first home

€250,000 flat with 20% deposit (€50,000). €200,000 mortgage over 25 years at 3.2% fixed: payment ~€969/mo. Real APR closer to 3.7% once tied insurance and pension plans are added.

Refinance after a rate drop

Current loan: $250,000 at 7.5% with 22 years left (payment ~$1,930). Refinance to 6.0% same term: payment falls to ~$1,710 — saves ~$58,000 in interest after closing costs.

Mexico — bank mortgage

$2.5M MXN home with 20% down. Loan of $2M MXN over 20 years at 10.5% fixed: payment ~$19,970/mo. Need ~$57,000/mo net income for the payment to stay within Infonavit/bank 35% cap.

Mortgage Calculator: Monthly Payment, Total Interest, and Full Amortization Table

A mortgage is likely the largest single financial commitment most households will ever make. Knowing your exact monthly payment, total interest cost, and how your loan balance evolves over time is not optional — it is the baseline for any purchase decision. This guide explains how a mortgage calculator works, the mathematics behind it, and how to use the results to compare lenders and scenarios.

The French Amortization Formula: What the Calculator Solves

The standard mortgage worldwide uses the French amortization method: a constant monthly installment (cuota) that gradually shifts from being mostly interest to being mostly principal. The formula for that constant installment is:

M = P × [r(1+r)^n] / [(1+r)^n − 1]

Where:

P = principal (loan amount)
r = monthly interest rate = annual nominal rate ÷ 12
n = total number of monthly payments = years × 12
M = monthly installment (principal + interest, before taxes/insurance)

Worked example: You borrow EUR 200,000 at a fixed nominal rate of 3.50% for 25 years (300 months).

r = 3.50% ÷ 12 = 0.2917% per month = 0.002917
n = 25 × 12 = 300
M = 200,000 × [0.002917 × (1.002917)^300] / [(1.002917)^300 − 1]
M ≈ EUR 1,001/month

Over 300 payments: total paid = EUR 300,300. Total interest = EUR 100,300 — roughly 50% of the original principal.

How the Amortization Schedule Works

Each monthly payment of EUR 1,001 is split into interest and principal. The split changes each month:

Month 1: Interest = EUR 200,000 × 0.2917% = EUR 583. Principal repaid = EUR 1,001 − EUR 583 = EUR 418. Remaining balance = EUR 199,582.
Month 60 (year 5): Outstanding balance ≈ EUR 179,200. Interest = EUR 522. Principal = EUR 479.
Month 150 (year 12.5): Outstanding balance ≈ EUR 148,000. Interest = EUR 431. Principal = EUR 570.
Month 300 (final): Nearly all of the EUR 1,001 goes to principal.

This is the fundamental mechanic: in early years you are primarily paying interest; in later years you are primarily reducing principal. This is why making extra principal payments in years 1–5 dramatically reduces total interest — those extra payments work on the full outstanding balance.

Interest Rate vs APR/TAE: Which to Compare

The nominal rate (TIN in Spain, tasa nominal in Mexico) determines your monthly installment. The APR (Annual Percentage Rate — called TAE in Spain, CAT in Mexico) includes the nominal rate plus all mandatory fees, commissions, and linked insurance products, expressed as an annual percentage.

Always compare APR/TAE across lenders, not just the nominal rate. Two mortgages at 3.20% nominal can have TAEs of 3.48% and 4.05% if one requires a EUR 800/year home insurance policy with the bank that a market alternative costs EUR 300.

TAE formula for a mortgage:

TAE is the rate that equates the present value of all outgoing cash flows (installments + fees + insurance) to the loan amount. The bank is legally required to disclose it on the FEIN (European Standardized Information Sheet) in Spain, and on the offer letter in Mexico.

Current Market Rates (2026)

Market	Mortgage type	Typical rate	Key benchmark
Spain	Fixed 25 years	3.05%–4.00% TIN	ING / Openbank lowest
Spain	Variable 25 years	EURIBOR + 0.60–1.20%	12-month EURIBOR: 2.45%
Mexico	Fixed (bank)	9.5%–12.5% nominal	CAT 13%–18%
Mexico	INFONAVIT	10.45% nominal	Formal workers only
Colombia	Mortgage (UVR-indexed)	UVR + 7–9%	Banco de la República rate: 9.25%

Sources: Banco de España Boletín Estadístico 2025-Q4, Banxico survey 2025, Bancolombia product sheets 2026.

Down Payment Requirements by Market

The down payment — called enganche in Mexico, entrada or señal in Spain — is the gap the mortgage does not cover. Lenders set this based on LTV (Loan-to-Value = loan ÷ appraised property value).

Spain: Maximum LTV for primary-residence mortgages at most banks is 80%, meaning a minimum 20% down payment. Add 10–12% of the purchase price for buying costs (ITP or IVA, notary, registry). Total cash needed: approximately 30–32% of the purchase price.
Mexico: Banks typically require 10–20% enganche. INFONAVIT subscribers can use their accumulated housing sub-account as partial down payment, potentially reducing cash outlay to 0–5%.
Colombia: Banks lend up to 70% of the property value (UVR-indexed), requiring 30% equity or a Fondo Nacional de Garantías guarantee for buyers who qualify.

What to Watch For: Red Flags in Mortgage Offers

Origination fee (comisión de apertura): Some lenders charge 0.5–1.5% of the loan amount at signing. This fee is sometimes excluded from the TAE calculation to make the headline rate look lower. Confirm it is included in any comparison.

Mandatory linked products: Spanish banks commonly require home insurance and life insurance from their own subsidiaries as a condition of the discounted rate. Calculate whether the insurance premium exceeds the interest saving. Under Ley 5/2019, banks cannot mandate these products legally — but they can make them a condition of the lower rate.

Early repayment penalties: In Spain, fixed-rate mortgages may charge up to 2% of the repaid capital in the first 10 years (Ley 5/2019). In Mexico, CONDUSEF requires disclosure but does not cap the rate — read the contract carefully.

Floor clauses (cláusula suelo): A minimum-rate floor in variable mortgages was ruled abusive by Spain's Supreme Court and the TJUE in 2016 for contracts where they were not transparently disclosed. They should not appear in new contracts, but if you are refinancing an old one, check.

VAT or tax on insurance: In Spain, life insurance premiums attached to mortgages are subject to 0% insurance premium tax (IPS), but home insurance carries 6%. In Mexico, insurance linked to the mortgage carries the standard 16% IVA.

How to Use the Simúlalo Mortgage Calculator Effectively

Enter the loan amount (purchase price minus down payment).
Enter the nominal rate from the bank's official offer document (TIN, not TAE).
Set the term in years — run scenarios at 20, 25, and 30 years to see the installment vs. total-interest tradeoff.
Read the amortization table — scroll to year 5 and year 10 to see outstanding balance at key refinancing decision points.
Compare two scenarios side by side: the best fixed rate offered and the current variable rate (EURIBOR + spread). The variable scenario shows the break-even: how many years of variable savings would it take to cover the risk of a 1-point EURIBOR rise?

The calculator does not include insurance, taxes, or notary fees — those belong in your total budget, not in the amortization formula. Plan for closing costs separately.

Key Ratios Lenders Check: LTV and DTI

LTV (Loan-to-Value): Loan amount ÷ Appraised property value × 100. A EUR 160,000 loan on a EUR 200,000 property is 80% LTV. Most Spanish and Mexican banks cap standard programs at 80% LTV — meaning you need at least 20% from your own funds. Higher LTV typically means a higher rate or a mandatory mortgage insurance premium.

DTI (Debt-to-Income): Total monthly debt payments ÷ Gross monthly income × 100. Banco de España guidelines cap the housing installment at 30–35% of net income. Including all existing debts (car loan, student loan, credit cards), the total DTI ceiling is typically 40–43%. Exceeding this threshold requires a larger down payment, a co-borrower, or a lower loan amount.

FEIN (Ficha Europea de Información Normalizada): Spain's legally required binding pre-contract document, delivered at minimum 10 business days before signing. It specifies the exact TIN, TAE, amortization schedule, all linked products and their costs, and the total amount payable over the loan life. Always request the FEIN from every lender you seriously consider — comparing FEIN documents is the most reliable way to make a final decision.

Mortgage Calculator

Methodology