For a small US business, ERP is the system that runs accounting, orders, purchasing, inventory and operations from one set of data. The US-specific test is whether it can calculate and report sales tax in every state where you have nexus, produce 1099 data for contractors, connect cleanly to payroll, and keep working as you add channels, locations and states.
This guide is for owners, controllers and operations leads in US businesses that have outgrown basic accounting software and spreadsheets. The federal and multi-state facts below were checked on the IRS website, the Supreme Court opinion and the Streamlined Sales Tax Governing Board site in October 2026. State rules vary and change, so confirm your obligations with a CPA or sales tax adviser. Nothing here is tax advice.
What should a small US business look for in an ERP?
Look for five things beyond core accounting: sales tax handling across states, contractor and information reporting, a clean payroll connection, inventory that matches reality, and integrations that do not need rekeying. The table shows what to test.
| Requirement | Why it matters in the US | What to test in a demo |
|---|---|---|
| Multi-state sales tax | Each state sets its own rules for remote sellers, rates and product taxability | Ship the same order to three states and check the tax and the report |
| Exemption certificates | Resale and exempt customers must be documented | Store a certificate, apply it, see what happens when it expires |
| 1099 reporting | Contractor payments must be tracked and reported | Flag a vendor as 1099, pay them, run the year-end report |
| Payroll connection | Payroll usually runs in a separate service | Import a payroll journal by department or job |
| Integrations | E-commerce, marketplaces, payments, banks, CRM, shipping | Place a web order and follow it to cash in the bank |
If your workflows are what set you apart and no package fits them, our custom ERP software page explains how we build ERP modules around them, connected to the tax and payroll services you already use.
How does multi-state sales tax affect your ERP?
Since South Dakota v. Wayfair, decided by the US Supreme Court on June 21, 2018, states can require sellers to collect sales tax on sales delivered into the state even without a physical presence there. The Streamlined Sales Tax Governing Board summarises the ruling as allowing states to require collection "regardless of physical presence". In practice, a small online seller can become responsible for collecting tax in states where it has no office, warehouse or staff.
Each state sets its own economic nexus thresholds, rates, product rules and filing frequencies, and they change. Do not hard-code them in an ERP. What the ERP needs instead:
- Destination-based tax calculation. Tax is usually worked out from the ship-to address, including local rates, which is why most businesses use a dedicated tax engine connected to the ERP rather than tax tables maintained by hand.
- Product taxability codes. Clothing, food, software and services are taxed differently across states. Each item needs a code the tax engine understands.
- Nexus monitoring. Reports of sales and transaction counts by state, so you can see when you approach a state's threshold.
- Exemption certificate management. Store certificates against customers, apply them automatically, and flag expired ones.
- Marketplace awareness. Many states make marketplaces responsible for collecting tax on sales they facilitate, so your ERP must record whether a marketplace order already had tax collected, to avoid double counting.
- Filing data by jurisdiction. Whether you file yourself or use a service, the ERP must produce tax collected by state and locality, reconciled to the ledger.
The Streamlined Sales Tax Governing Board, which administers a multistate agreement with 23 full member states as of October 2026, contracts with Certified Service Providers that offer tax calculation software. Its site states that this software and the related services are available at no charge to remote sellers in states where the seller is a "volunteer seller". Check whether that applies to you before buying a tax engine.
What 1099 and information reporting does your ERP need to support?
Your ERP should identify which vendors receive Forms 1099, store their taxpayer identification numbers, track reportable payments by box, and produce year-end data for filing. As of October 2026, the IRS instructions for Forms 1099-MISC and 1099-NEC state:
- Form 1099-NEC is filed for each person to whom you paid at least $2,000 for services in the course of your business, for payments made after December 31, 2025. The previous threshold was $600 for payments made before 2026.
- The threshold may be adjusted for inflation beginning in calendar year 2027, so do not hard-code $2,000 in your system. Store it as a setting by year.
- Form 1099-NEC is filed with the IRS and furnished to recipients on or before January 31.
- You can use Form W-9 to obtain a payee's TIN, and backup withholding can apply where a TIN is not provided.
On the receiving side, the IRS states that the One, Big, Beautiful Bill reinstated the Form 1099-K threshold for third party settlement organizations: they are not required to file Forms 1099-K unless payments to a payee exceed $20,000 and the number of transactions exceeds 200. If you sell through payment apps or marketplaces, your ERP should let you reconcile any 1099-K you receive against your own sales records.
How should payroll connect to a small-business ERP?
Most small US businesses run payroll through a payroll provider and import the results into the ERP. Payroll involves federal, state and sometimes local withholding and filings, which specialist providers keep current.
The IRS states that employers who withhold income tax, Social Security or Medicare tax file Form 941 each quarter, due by the last day of the month after the quarter ends (April 30, July 31, October 31 and January 31), and that Forms W-2 are furnished to employees and filed with the Social Security Administration by January 31. The IRS notes the due date for 2026 Forms W-2 with the SSA is February 1, 2027, because January 31 falls on a weekend.
The ERP's job is to:
- import payroll journals each pay run, split by department, location, job or grant;
- send hours from time tracking or job management into payroll, if your operations system records them;
- allocate labor cost to jobs and products for margin reporting;
- keep payroll liabilities in the ledger reconciled to what the provider pays.
Our guide to the ERP HR and payroll module covers when payroll belongs inside the ERP.
Which integrations matter most for a growing US business?
Order-to-cash integrations matter most: your online store and marketplaces, payment processors, the bank, shipping, and the tax engine. Then CRM and purchasing.
| Integration | Data that should flow | Common failure |
|---|---|---|
| E-commerce store and marketplaces | Orders, customers, tax collected, refunds, inventory levels | Stock oversold because levels sync too slowly |
| Payment processors | Payouts, fees, chargebacks | Payouts posted as one lump, so fees and refunds never reconcile |
| Tax engine | Tax per line, exemptions, jurisdiction data | Tax calculated on the store but not stored in the ERP |
| Bank feeds | Transactions for reconciliation | Duplicate imports after a reconnection |
| Shipping | Labels, tracking, freight cost | Freight cost never reaches the order margin |
| CRM | Accounts, quotes, orders, credit status | Sales sees a customer as active while finance has them on hold |
Read our guides to ERP and e-commerce integration and ERP and CRM integration for the design detail. If you are connecting systems you already own, our ERP integration services page explains how we approach it.
What are the ERP options for a small US business?
| Option | Good fit | Watch out for |
|---|---|---|
| Accounting software plus apps | Service firms and simple product businesses in one or two states | Data spread across apps, weak inventory, reports stitched by hand |
| Small-business ERP suite | Product businesses selling in many states and channels | Implementation effort, and processes bending to the package |
| Open-source ERP | Teams with technical capacity or a strong partner | You own hosting, upgrades and the tax engine connection |
| Custom ERP modules | Businesses whose workflows are their advantage | Needs a clear owner and a good brief; connect to proven tax and payroll services rather than rebuilding them |
A sensible pattern for many growing businesses is a hybrid: keep proven services for tax calculation and payroll, and put custom modules where the business is different, such as job costing, production scheduling, rentals or field service. For the general trade-offs, see ERP vs custom development.
Small-business ERP scorecard (US)
Score each option from 0 to 3 in a demo using your own data.
- Connects to a sales tax engine and stores tax per line by jurisdiction
- Reports sales and transactions by state for nexus monitoring
- Manages exemption certificates with expiry alerts
- Records whether marketplace orders had tax collected by the marketplace
- Tracks 1099 vendors, TINs and reportable payments, with the threshold stored as a setting
- Imports payroll journals by department, location or job
- Syncs inventory with every sales channel fast enough to avoid overselling
- Reconciles processor payouts into sales, fees and refunds
- Shows margin by product, job or customer
- Exports all data in an open format
When is a new ERP the wrong move?
If you sell in one state, carry little inventory and have a handful of contractors, good accounting software, a payroll provider and a sales tax app will serve you better than an ERP. An ERP is also the wrong fix for a broken process; it will automate the problem. And do not build your own sales tax rates or payroll calculations: those are specialist services that track constant rule changes, and connecting to them is cheaper and safer than replicating them.
How to start
List the states you ship to and your sales by state, your sales channels, payment processors, payroll provider, number of 1099 vendors, inventory locations and the five tasks that take the most time each month. Our ERP RFP template turns that into a document vendors and developers can respond to.
Then discuss the project with us. Timeline Digital builds 2 to 3 key modules as a free pilot before the full project starts, so you can test custom workflows connected to your existing tax and payroll services before you commit.