October 1, 2026 brings several important sales tax changes that ecommerce and remote sellers need to know about.
Three of the biggest developments are:
- Washington, D.C.: The general sales tax rate increases from 6% to 7%
- California: New local and district tax rates take effect, including a 0.5% increase across Los Angeles County
- Pennsylvania: The state begins enforcing new destination-based local sales tax rules for sales delivered into Philadelphia and Allegheny County
If your business sells across multiple states, the start of Q4 is a good time to review your sales tax nexus, registrations, checkout settings and filing setup.
What Sales Tax Changes on October 1, 2026?
The start of a new quarter frequently brings state and local sales tax changes, and October 1, 2026 is no exception. For online businesses, the difficulty isn’t simply knowing that a rate has changed.
You also need to know:
- Where your business has sales tax nexus
- Which sales are taxable
- Which state and local rates apply
- Whether your ecommerce system has been updated
- Whether a marketplace is collecting on your behalf
- How the tax should be reported on your returns
Three changes are particularly important for remote sellers entering Q4.
Ecommerce businesses selling across the US should review their sales tax setup from October 1, 2026. D.C.’s general rate increases to 7%, California introduces multiple local rate changes, and Pennsylvania begins enforcing destination-based local sales tax collection in Philadelphia and Allegheny County. Even a small rate change can create a significant underpayment when multiplied across thousands of online transactions.
1. Washington, D.C. Sales Tax Increases to 7%
One of the clearest October 1 changes is in the District of Columbia. The general D.C. sales tax rate increases from 6% to 7% beginning October 1, 2026.
This applies to the general category of taxable tangible personal property and selected taxable services. Certain products and services remain subject to their own special rates.
Example
An ecommerce business makes a $1,000 taxable sale delivered to a customer in Washington, D.C.
Before October 1: $1,000 × 6% = $60
From October 1: $1,000 × 7% = $70
That’s only a $10 difference on one transaction.
But across $500,000 of taxable sales, a one-percentage-point increase represents $5,000 of additional tax. Businesses with D.C. nexus therefore need to ensure their systems are applying the new rate to transactions occurring from October 1.
Do Remote Sellers Need to Collect D.C. Sales Tax?
Potentially, yes, remote sellers can create economic nexus in Washington, D.C. based on their sales into the District. This means an ecommerce company does not necessarily need an office or employee in Washington to have a collection obligation.
If you’re already registered for D.C. sales tax, the immediate priority is ensuring the new 7% general rate is being applied correctly. If your sales have grown substantially during 2026 and you’re not registered, you should also review whether you’ve created economic nexus.
2. California Sales Tax Rates Change on October 1
California also introduces a number of district sales and use tax changes from October 1, 2026. California’s statewide base sales and use tax rate remains 7.25%, but local district taxes can push the actual rate significantly higher depending on the customer’s location.
Among the October changes are new rates in:
- Los Angeles County
- Perris
- Red Bluff
- Various cities within Los Angeles County
This is why online sellers should avoid thinking of California as having one universal sales tax rate. The correct rate can depend on the precise destination of the sale.
Los Angeles County Sales Tax Increases by 0.5%
One of the most significant California changes affects Los Angeles County. From October 1, 2026, a new 0.5% countywide district tax takes effect.
In the unincorporated areas and incorporated cities without an additional city district tax, the combined rate shown by the CDTFA increases from: 9.75% → 10.25%
Some cities within Los Angeles County have additional district taxes, meaning their combined rates can be even higher. For ecommerce sellers shipping significant volumes of products into Southern California, this is an important checkout change.
Why California Sellers Need Accurate Customer Addresses
California’s local tax system makes accurate sourcing particularly important. A seller should not simply see “Los Angeles” or a California ZIP code and assume one tax rate applies. Depending on the exact destination, different district taxes may apply.
The CDTFA provides an address-based tax rate lookup tool to help businesses determine the applicable rate. For ecommerce businesses using automated tax software, October 1 is a good opportunity to check that those systems have received the latest California rate updates.
3. Pennsylvania Starts Enforcing New Local Sales Tax Rules
Another major October 1 development is in Pennsylvania. Pennsylvania’s 6% state sales tax rate is not changing.
Instead, Pennsylvania is changing how its additional local sales taxes are applied to sales delivered into:
- Philadelphia
- Allegheny County
The Department of Revenue begins enforcing the new rules on October 1, 2026.
Previously, Pennsylvania local sales tax was generally based on the vendor’s location. Under the new rules, the local tax is based on the destination of the taxable product or service.
What Does This Mean for Pennsylvania Orders?
Businesses already required to collect Pennsylvania’s 6% sales tax must also collect:
| Customer Destination | State Rate | Local Rate | Combined Rate |
| Most of Pennsylvania | 6% | — | 6% |
| Allegheny County | 6% | 1% | 7% |
| Philadelphia | 6% | 2% | 8% |
For remote sellers, this means the customer’s delivery address becomes particularly important. A taxable product delivered to Philadelphia can now require 8%, while the same product delivered elsewhere in Pennsylvania may only require 6%.
What Should Shopify and Ecommerce Sellers Check Today?
If you’re selling directly through Shopify, WooCommerce, BigCommerce or another ecommerce platform, there are several things worth checking at the start of Q4.
Check your tax rates
Make sure October 1 rate changes have been correctly incorporated into your checkout system. Pay particular attention to:
- Washington, D.C.
- California
- Philadelphia
- Allegheny County
Check your customer addresses
Local sales tax can depend on the exact delivery location. Accurate customer address information becomes increasingly important when state, county, city and district taxes overlap.
Check your nexus
A tax rate change is irrelevant if your business doesn’t have an obligation to collect in that jurisdiction. However, if your business has grown during 2026, you may have crossed an economic nexus threshold without realising it.
Check your registrations
If nexus has been created, make sure the correct sales tax accounts have been opened. Collecting sales tax without the appropriate registration can create its own compliance problems.
What About Amazon and Marketplace Sellers?
Marketplace sellers need to distinguish between marketplace and direct sales. Where Amazon, Walmart, eBay or another marketplace facilitator is legally responsible for collecting and remitting sales tax, the marketplace generally handles tax calculation for those transactions. However, that does not necessarily solve the problem for businesses also making direct sales.
For example, a company could sell through:
- Amazon
- Shopify
- Its own website
Amazon may handle the tax on its marketplace transactions while the business remains responsible for correctly calculating tax on its Shopify and direct website orders. This is one of the most common areas of confusion for growing ecommerce businesses.
Example: Multi-State Shopify Seller
Imagine a Shopify business based in Florida that already has nexus in several states.
On October 1 it receives three taxable $500 orders:
Washington, D.C.
General tax at 7% = $35
Los Angeles County
The applicable California rate depends on the customer’s precise location and relevant district taxes.
Philadelphia
8% combined tax = $40
The business’s tax system needs to identify each destination and calculate the correct amount automatically. If the system is using outdated Q3 rates or incorrect sourcing rules, the business could begin under-collecting tax from the first day of Q4.
What Happens If You Charge the Wrong Rate?
A checkout error doesn’t necessarily remove the seller’s tax liability. If your business should have collected $10,000 but only collected $8,000 from customers, the state can still expect the correct amount to be remitted. That can leave the business funding the $2,000 difference from its own money, potentially alongside penalties and interest.
For high-volume ecommerce businesses, seemingly minor rate errors can therefore become expensive.
October Is Also a Good Time for a Nexus Review
Q4 rate changes provide a useful reminder to look beyond tax rates.
Ask: Where has my business grown during 2026?
If sales have increased substantially in a particular state, you may have crossed its economic nexus threshold. Likewise, physical activities such as:
- Amazon FBA inventory
- A new 3PL
- Employees
- Warehouses
- Other in-state business activity
can create separate nexus issues.
Correct tax rates only help if your business is registered everywhere it actually needs to be.
Common Q4 Sales Tax Mistakes
Watch out for:
- Using outdated sales tax rates after October 1
- Applying one blanket California rate
- Missing Philadelphia or Allegheny County local tax
- Assuming Amazon handles tax on your Shopify sales
- Failing to review economic nexus as sales grow
- Collecting tax without registering
- Registering but forgetting ongoing returns
- Relying on ZIP codes when a more precise address calculation is required
For multi-state sellers, sales tax compliance is an ongoing process rather than a one-time registration exercise.
FAQs
What sales tax changes take effect October 1, 2026?
Important changes include D.C.’s general sales tax increasing to 7%, multiple California district tax changes and Pennsylvania beginning enforcement of its new destination-based local tax rules for Philadelphia and Allegheny County.
What is the Washington, D.C. sales tax rate from October 1, 2026?
The general rate increases from 6% to 7%. Certain products and services have separate tax rates.
Is California’s statewide sales tax rate increasing?
No, California’s statewide base rate remains 7.25%. However, several local district rates change on October 1, including a new 0.5% countywide tax in Los Angeles County.
What is the Los Angeles County sales tax rate from October 1?
The CDTFA shows the county rate increasing from 9.75% to 10.25% in areas without an additional city district tax. Some cities have higher combined rates.
Is Pennsylvania’s 6% sales tax increasing?
No. The statewide rate remains 6%. The October 1 development concerns destination-based collection of Philadelphia’s additional 2% and Allegheny County’s additional 1% local taxes.
Do these changes affect remote sellers?
Potentially. Remote sellers with sales tax nexus in the relevant jurisdiction need to ensure they’re collecting the correct applicable tax on taxable direct sales.
Final Thoughts
October 1, 2026 is an important date for ecommerce sales tax compliance. D.C.’s general sales tax rises to 7%. California introduces another wave of local rate changes. Pennsylvania begins enforcing new destination-based local sales tax rules. But the bigger lesson for ecommerce businesses is that sales tax rules don’t stand still. Rates change. Nexus thresholds are crossed. Businesses add new sales channels. Inventory moves into new states. A sales tax setup that was correct six months ago may not necessarily be correct today.
RJM Tax Exemption helps ecommerce and remote sellers understand where they have US sales tax obligations and keep their registrations and filings compliant as their businesses grow. If your US sales have grown during 2026 and you’re unsure where you should now be registered, schedule a meeting with RJM Tax Exemption to review your sales tax position.
