Montgomery County MD Property Tax: Pay, Lookup & Calculate Online
Need to pay, find, or understand a Montgomery County Maryland property tax bill? Use the official County portal for the live balance, but use this guide first to know which number to enter, which payment option avoids fees, what the September 30 and December 31 dates mean, and what to do if a payment, lender, revised bill, or tax lien warning creates confusion.
What Montgomery County property taxpayers usually need first
Choose the row that matches your situation. This page is built to reduce scrolling, wrong-office calls, and payment mistakes.
Fast action board
- 1Need to pay? Use the official Real Property Tax Portal. Electronic check is the fee-saving route listed by the County.
- 2Need to find the bill? Search by 8-digit bill number, 8-digit account number, or street address without street suffix, such as “123 MAIN.”
- 3Mailing a check? Postmark is not enough. Montgomery County says payments must be received by the due date.
- 4Mortgage lender pays? You may still receive the tax bill. Revised or supplemental bills may need to be sent to your lender by you.
- 5Payment not showing? Check with your bank first. If not applied after 10 days, contact MC311 and create a service request.
Official pages to keep open
How to look up a Montgomery County MD real property tax bill
The official portal gives three practical search choices. Use the cleanest one you have.
| Search Method | Use When | Common Mistake |
|---|---|---|
| 8-digit bill number | You have the paper or PDF tax bill. | Entering old-year bill number or missing leading digits. |
| 8-digit account number | You have account details from the property record or bill. | Confusing account number with parcel ID from another source. |
| Street address | You do not have bill/account number. | Adding suffix. The portal example says use address without street suffix, such as 123 MAIN. |
1
Open the official real property tax portal
Use county portal first, not third-party payment pages.
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Go to the official Montgomery County Real Property Tax Payment Portal. Confirm the page says Montgomery County, Maryland before entering tax or payment details.
2
Search by bill, account, or clean street address
Address search works best without suffix.
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Try bill number first, then account number, then address. For address, remove suffixes like Street, Road, Avenue, Lane, Drive, Court, or Place if the portal does not find the property.
3
Match the property before paying
Do not pay only because the name looks right.
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Confirm property address, owner/account details, tax year, payment option, prior-year note, lien note, credit, WSSC or special charge if shown, and the exact amount due.
Montgomery County property tax payment options and fees
The county lists four main payment routes. Electronic check is the cleanest fee-saving option listed by the official portal.
| Payment Method | Official Detail | Best For | Watch Out |
|---|---|---|---|
| Online | E-check: no fee. Credit/debit: 2.3% fee. | Fastest self-service payment. | Card fee is processor fee and not refundable. |
| Phone | Call 240-777-8898. E-check: no fee. Credit/debit: 2.45% fee. | Taxpayers who prefer phone payment. | Write down confirmation details. |
| In person | 27 Courthouse Square, Suite 200, Rockville, MD 20850. | Cash, check, in-person support. | No money orders listed. |
| Check payable to “Montgomery County Government MD.” Mail with payment slip. | Check payment with coupon. | Postmark is not accepted. |
1
Use e-check when you want to avoid listed payment fee
The official portal lists electronic check as no fee.
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When paying online or by phone, compare electronic check versus card. The portal lists credit/debit card fees, while e-check is listed as no fee.
2
Double-check bank and account details
County says taxes are not paid until funds clear.
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Montgomery County warns that property taxes are not considered paid until funds remitted have cleared the County bank account. The person scheduling the payment is responsible for entering correct information.
3
Save proof immediately
Useful for posting delays, lender questions, or MC311 requests.
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Save confirmation number, payment date, payment method, amount, account/bill number, property address, and a screenshot/PDF. If not applied after 10 days, contact MC311 and request help.
Montgomery County MD property tax due dates and late-payment rules
These dates answer the most common searcher question: “When is my Montgomery County property tax due?”
| Bill Type | Due Date | Late Starts | What It Means |
|---|---|---|---|
| Annual tax bill | September 30 | October 1 | Full annual payment must be received by September 30. |
| First semi-annual installment | September 30 | October 1 | First half payment for eligible semi-annual taxpayers. |
| Second semi-annual installment | December 31 | January 1 | Second half payment for eligible semi-annual taxpayers. |
| Supplemental / revised bill | 30 days from issue | After due date | Common after assessment changes or new construction. |
Late charge
County information says delinquent taxes are subject to interest and penalty at 1 2/3% per month until paid in full.
Tax lien risk
Delinquent taxes, including unpaid interest and penalty, are a lien on the property and can be sold according to state law.
Tax bills posted
County FAQ says annual and semi-annual bills are mailed in July and posted to the website by July 1.
Processing time
Payments around September 30 and December 31 can take time to appear. If not applied after 10 days, contact MC311.
Annual vs semi-annual property tax payments
Maryland’s semi-annual schedule often confuses homeowners because the bill may show more than one payment option.
Owner-occupied homes
Principal residential properties generally use the semi-annual payment schedule unless the taxpayer chooses to pay both payments by September 30.
Escrowed taxes
If your lender escrows your taxes and you want annual payment, County guidance says you must notify the lender by May 1.
Rental / non-owner issues
County review guidance says owner-occupied residential property owners are eligible; rental property may not get the same semi-annual bill option.
How to estimate Montgomery County Maryland property tax
Use this to understand the bill. The official Montgomery County bill is the final source for what you owe.
Simple property tax estimate formula
Estimated tax = taxable assessment × applicable rates + special charges − credits.
| Bill Item | What It Means | Where To Check |
|---|---|---|
| Assessment | Value used for tax calculation. | Maryland State Assessment office / SDAT records. |
| County tax | Montgomery County real property tax. | County tax bill. |
| Municipal tax | Collected for participating municipalities. | Bill line items; county collects for many municipalities. |
| Credits | Homestead or other credits reducing tax due. | Bill credit lines and Maryland tax credit records. |
| Special charges | Items such as WSSC remaining or other charges if shown. | Bill details; contact related agency if needed. |
Payment, lender, supplemental bill, or tax lien problem: who to contact
Use this table before calling. It helps avoid the wrong department.
| Problem | First Action | What To Prepare |
|---|---|---|
| Payment not posted | Check bank/card activity, then MC311 if not applied after 10 days. | Receipt, confirmation, amount, date, account/bill number. |
| Lender did not pay | Call mortgage servicer and compare bill/escrow statement. | Tax bill, escrow statement, lender payment proof. |
| Supplemental bill received | Do not assume lender got it. Send it to lender if escrowed. | Supplemental bill, issue date, due date, account number. |
| Assessment seems wrong | Contact State Assessment/SDAT process, not just County payment office. | Assessment notice, comps, property facts, appeal deadline. |
| Tax lien sale notice | Act immediately. Delinquent tax, interest, penalty, and fees can grow. | Notice, account number, payoff amount, proof of payment if any. |
Real property tax vs business personal property tax
Montgomery County has separate systems. Homeowners usually need real property tax. Businesses may need personal property tax.
Real property tax
Use this for homes, land, condos, commercial real estate, and real estate tax bills. Search by 8-digit bill/account or address.
Business personal property tax
Use this for business personal property records. The County system says tax information from 1999 to current is available online.
Montgomery County Treasury Division office map
Use the map for in-person payment planning. Confirm hours, accepted payment type, and whether your issue can be handled online before visiting.
27 Courthouse Square, Suite 200, Rockville, MD 20850
The County’s Department of Finance notice says the Treasury Division moved to 27 Courthouse Square, Suite 200, Rockville, MD 20850. Handicapped parking is noted on Jefferson Street between Washington Street and Maryland Avenue.
Official Montgomery County property tax resources
Use these official pages for live actions. The information above explains the rules so you only leave this guide when you need to pay, look up a live balance, or contact the County.
Montgomery County Maryland property tax FAQs
Short answers for the questions taxpayers usually search before paying or calling.
QHow do I pay Montgomery County MD property tax online?▾
Use the official Real Property Tax Payment Portal. Search by 8-digit bill number, 8-digit account number, or address without street suffix.
QWhat are the due dates?▾
Annual bills and first semi-annual installments are due September 30. Second semi-annual installments are due December 31. Supplemental and revised bills are due 30 days from issue.
QDoes Montgomery County accept postmarks?▾
No. The County says postmarks are not accepted. Payments must be received by the due date.
QWhat is the cheapest online payment method?▾
The official portal lists electronic check as no fee. Credit/debit card payments have a percentage fee.
QCan I pay by phone?▾
Yes. Call 240-777-8898. The official payment page lists phone payment by electronic check or credit/debit card.
QWhere is the in-person payment office?▾
The Treasury Division is listed at 27 Courthouse Square, Suite 200, Rockville, MD 20850.
QWhere do I mail property tax payment?▾
The official portal lists mailing checks with the payment slip to Montgomery County, MD, P.O. Box 5561, Binghamton, NY 13902-5561. Do not send money orders.
QWhat if my payment is not showing?▾
Check with your financial institution first. County guidance says if payment has not been applied after 10 days, contact MC311 and create a service request.
QWhat is the late penalty?▾
County information says delinquent taxes are subject to interest and penalty at 1 2/3% per month until paid in full, calculated on the net amount after credits.
QIs this an official county website?▾
No. PropertyTaxUSA.org is an independent guide. Verify live balances, due dates, payment status, credits, and lien notices through official Montgomery County resources.
Bottom line
For Montgomery County Maryland property tax, use the official portal for live lookup and payment, but understand the rules before you pay. Search with an 8-digit bill number, 8-digit account number, or clean street address. E-check is the fee-saving option listed by the County. Annual and first semi-annual bills are due September 30; second semi-annual bills are due December 31. Postmarks are not accepted.
Independent guide notice: This page is informational only and is not Montgomery County Government, MC311, the Department of Finance, SDAT, or a payment processor.