Collin County Mortgage Calculator

Collin County mortgage calculator: plan the whole payment

Collin County, north of Dallas, includes Plano, Frisco, McKinney, Allen, and fast-growing towns like Prosper, Celina, Anna, and Melissa. It is one of the fastest-growing counties in Texas, and much of the new housing comes with special district taxes and HOA dues. This page gives you current Collin County numbers, a worked example near the local median, and the Texas tax and loan rules that belong in any honest estimate. Summit Lending LLC (NMLS 2394434) is a mortgage broker based in Garland, Utah. We compare loans from multiple wholesale lenders and can turn your calculator result into a real quote for a home in Collin County.

Ready to shop? Start a Collin County preapproval, or read about Collin County purchase loans.

Summit Lending LLC, NMLS 2394434, is based at 4542 W 14800 N, Garland, UT 84312 and serves borrowers in Utah, Texas, Idaho, Wyoming, Arkansas, and Arizona. Call 385-200-1470 or email [email protected].

Collin County numbers to start with

Redfin put the Collin County median sale price at about $437,000 for the three months ending September 2026, down 1.1% from the same period a year earlier. About 1,316 homes sold in September, compared with 1,495 a year earlier, and homes took a median of about 74 days to sell, versus 68 days last year, with an average sale-to-list ratio near 96.8% (Redfin Collin County data). Prices are a little lower than a year ago, homes are taking longer to sell, and the average home sells several percent below list, so builders and sellers are often willing to help with closing costs or rate buydowns.

For city numbers, see the Plano mortgage calculator and nearby Allen, Wylie, Prosper, Celina, Anna, and Melissa. Many newer subdivisions in the northern part of the county sit in municipal utility districts (MUDs) or public improvement districts (PIDs), which add to the tax bill.

Rates set the base of every estimate. Freddie Mac's weekly survey put the average 30-year fixed rate at 7.40% for the week of October 8, 2026, up from 7.28% a week earlier and 6.30% a year ago. It was the seventh weekly increase in a row and the highest reading since November 2023. The 15-year average was 6.73% (AP report on the Oct 8 survey; weekly history in the PMMS archive and on FRED). Those are national averages for borrowers with strong credit and roughly 20% down, not Collin County quotes. Freddie Mac publishes a new reading every Thursday (PMMS page), so if you are running numbers a few weeks from now, update the rate first.

What goes into a Collin County payment

• Principal and interest. The calculator's core result, set by price, down payment, rate, and term.
• Property tax. Often the largest cost after principal and interest. The combined rate depends on the county, city, school district, and any special districts for the address. Many newer subdivisions in the county also pay MUD taxes or PID assessments.
• Homeowners insurance. Texas premiums run higher than in most states because of hail and wind. Get a real quote early, and check flood zone status even outside the coast.
• Mortgage insurance. PMI on conventional loans with less than 20% down, or FHA's annual premium.
• HOA dues. Very common, especially in newer master-planned communities.

Texas property tax and the homestead exemption

Property tax is usually the biggest line after principal and interest in Texas, because the state has no income tax and local governments lean on property tax instead. Texas voters approved Proposition 13 in November 2025, raising the school district homestead exemption to $140,000 (Ballotpedia; Texas Comptroller). That exemption only reduces the school portion of the bill. Counties, cities, and other districts set their own exemptions, if any. Once a home is your homestead, Texas also limits how much its appraised value can rise for tax purposes to 10% a year, not counting new improvements (Texas Tax Code Section 23.23).

For the estimate, look up the address on the Collin Central Appraisal District site and check the taxing units and current exemptions. In Collin County, check whether the address is in a MUD or PID, because those charges show up on the tax bill or as a separate assessment and builders do not always highlight them. If the seller had a homestead exemption or an over-65 freeze, your first bill could be higher than theirs. You file your own homestead application after you move in, and it is worth doing in your first year.

Worked example: a $437,000 home in Collin County

Take a $437,000 home near the Collin County median with 10% down. The loan is $393,300. At 7.40%, principal and interest on a 30-year fixed is about $2,723 a month. At last year's 6.30%, the same loan would have been about $2,434, so the rate change alone adds about $289 a month.

A 15-year fixed at 6.73% raises the payment to about $3,476, while total interest drops to about $232,378, compared with about $587,027 over 30 years at 7.40%. Add tax, insurance, PMI, and HOA dues for the full number. If it is more than you want to carry, compare a lower price point, a larger down payment, a temporary or permanent rate buydown paid by the seller, or Texas state down payment assistance.

How the loan type changes your Collin County result

Most online calculators assume a conventional loan with a fixed rate, which can make the number look better or worse than what you would actually get. Here is how the same $437,000 Collin County home changes by program, using the 7.40% survey average as a stand-in rate. Your actual rate will differ by program and profile.

Conventional

Qualified buyers can put as little as 3% down on a one-unit primary home, which is $13,110 on $437,000 (Fannie Mae eligibility matrix). Below 20% down you pay private mortgage insurance, and you can ask to cancel it once the balance reaches 80% of the original value (CFPB on PMI). PMI is priced by credit score and down payment, so add it as a separate line in the calculator rather than guessing.

FHA

FHA requires 3.5% down with a 580 or higher score (HUD FHA overview). It also adds two insurance costs a basic calculator often skips: an upfront premium of 1.75% that is usually financed into the loan, and an annual premium paid monthly. For a base loan of $726,200 or less with more than 95% loan-to-value, the annual rate is 0.55% (HUD Mortgagee Letter 2023-05). On $437,000 with 3.5% down, the base loan is $421,705, the upfront premium adds $7,380, and principal and interest on $429,085 is about $2,971 at 7.40%. The monthly premium adds roughly $193, for about $3,164 before taxes and insurance. The 2026 FHA one-unit limit in Collin County is $563,500, so this price fits.

VA

Eligible veterans and service members can buy with no down payment and no monthly mortgage insurance (VA purchase loans). A one-time funding fee applies unless you are exempt, and for first use with less than 5% down it is 2.15% of the loan (VA funding fee). Financing that fee on $437,000 brings the loan to about $446,396, with principal and interest near $3,091 at 7.40%.

USDA

USDA guaranteed loans allow no down payment in eligible rural areas for households under the income limits (USDA guaranteed loans). A few rural areas on the eastern and northern edges of the county can be eligible, but most of the county is not. Check an address on the USDA eligibility map before you count on it.

2026 loan limits in Collin County

The 2026 conforming loan limit for a one-unit home in Collin County is $832,750 (FHFA announcement, FHFA county file). The FHA one-unit limit is $563,500 for the Dallas-Fort Worth-Arlington metro, which also covers Dallas County, Denton County, and Tarrant County (HUD announcement, HUD lookup). Above $832,750 is jumbo territory, which is common in parts of Frisco, Prosper, and west Plano.

Down payment help in Texas

Statewide programs are available to Collin County buyers. TDHCA's My First Texas Home and My Choice Texas Home offer up to 5% assistance (TDHCA program chart), and TSAHC offers up to 5% through Homes for Texas Heroes and Home Sweet Texas (TSAHC programs). Income and price limits apply, and some assistance is a second loan that has to be repaid. Add any second-loan payment to your estimate. Our Collin County first-time home buyer guide goes deeper.

From a calculator estimate to a real number

1. Run a few scenarios here. Try two prices, two down payments, and both a 30-year and 15-year term so you know your range.
2. Get preapproved. A preapproval means a lender checked your credit, income, and assets. The CFPB points out that lenders use the terms prequalification and preapproval differently, so ask what was verified (CFPB comparison). Several mortgage credit checks within 45 days count as one inquiry for most scoring models, so shopping does not hurt your score more than once (CFPB on credit checks).
3. Compare Loan Estimates. Lenders must send a Loan Estimate within three business days of your application, and the standard format makes side-by-side comparison easy (CFPB on Loan Estimates).
4. Watch your debt-to-income ratio. Lenders compare your monthly debts, including the new payment, to gross monthly income (CFPB on DTI). A payment that fits your budget can still be too high for a program limit, or the reverse.
5. Check the final numbers. Your Closing Disclosure arrives at least three business days before closing. Compare it to your Loan Estimate line by line (CFPB on Closing Disclosures).

Calculators for nearby areas

Cities in and near the county: Plano, Allen, Wylie, Prosper, Celina, Anna, Melissa, and Sachse. Elsewhere in Texas: Dallas County, Denton County, Dallas, Little Elm, and Tarrant County. Or use the statewide Texas mortgage calculator.

Related pages

See the Collin County mortgage overview, Collin County refinancing, Collin County construction loans, Collin County reverse mortgages, and Collin County commercial loans. Statewide, compare Texas mortgage loans, Texas purchase loans, Texas refinancing, Texas preapproval, Texas mortgage calculator.

Sources

• Redfin, Collin County, TX housing market
• Redfin, Texas housing market
• AP via WTOP, Freddie Mac rates for Oct 8, 2026
• Freddie Mac PMMS archive
• Freddie Mac Primary Mortgage Market Survey
• FRED, 30-Year Fixed Rate Mortgage Average
• Ballotpedia, Texas Proposition 13 (2025)
• Texas Comptroller, property tax exemptions
• Texas Tax Code Chapter 23, appraisal methods (Section 23.23)
• Collin Central Appraisal District
• Fannie Mae Eligibility Matrix
• CFPB, private mortgage insurance
• HUD, Let FHA loans help you
• HUD Mortgagee Letter 2023-05, FHA annual MIP (PDF)
• VA purchase loan
• VA funding fee and closing costs
• USDA Single Family Housing Guaranteed Loan Program
• USDA property eligibility map
• FHFA, 2026 conforming loan limits
• FHFA 2026 county loan limit list
• HUD No. 25-145, 2026 FHA loan limits
• HUD FHA mortgage limits lookup
• TDHCA homebuyer program chart (PDF)
• TSAHC, loans and down payment assistance
• CFPB, prequalification vs. preapproval
• CFPB, when a lender checks your credit
• CFPB, What is a Loan Estimate?
• CFPB, debt-to-income ratio
• CFPB, What is a Closing Disclosure?

Information on this page is for general education and is current as of October 2026. It is not a commitment to lend or a rate quote. Program rules, limits, and availability change, and approval depends on your credit, income, assets, property, and lender guidelines. Summit Lending LLC, NMLS 2394434. Equal Housing Opportunity.