TL;DR
ConnectWise and Xero both have tax-code tables, and the sync layer maps between them. Australian MSPs map to Xero GST rates (10 percent standard, GST-free, BAS Excluded). UK MSPs map to Xero VAT rates (20 percent standard, reduced, zero-rated). US MSPs map to per-state sales tax rates. The mapping is one-to-one. Connect Zero ships with Australian defaults; international MSPs configure their own. Variance budget at BAS or VAT-return time should be zero.
The architectural shape of tax mapping
Every ConnectWise to Xero sync sits between two tax-code tables. The ConnectWise side has a Tax Code table (one row per treatment). The Xero side has a Tax Rates table (one row per rate). The sync layer holds a mapping table that joins them: for each ConnectWise tax code, which Xero tax rate to use.
The mapping is one-to-one in 95 percent of cases. ConnectWise "Standard GST" maps to Xero "GST on Income 10 percent" for an Australian MSP. ConnectWise "GST-Free" maps to Xero "GST Free Income". ConnectWise "Export" maps to Xero "GST Free Export". Simple lookup, no logic.
The remaining 5 percent of cases need a small amount of logic. Cross-border vendors with non-resident GST treatment. Compound tax rates in jurisdictions that have both federal and state sales tax. Reverse-charge VAT for UK business-to-business cross-border services. These are documented in the per-jurisdiction sections below.
Australian GST: the default Connect Zero mapping
The Australian MSP shape covers roughly 70 percent of our customer base, so the defaults are tuned for it. The Connect Zero sync ships with this mapping out of the box.
| ConnectWise tax code | Xero tax rate | Rate | BAS treatment |
|---|---|---|---|
| Standard GST | GST on Income | 10% | G1, G2 |
| GST-Free | GST Free Income | 0% | G3 |
| Input-Taxed | Input Taxed | 0% | G4 |
| Export | GST Free Exports | 0% | G2 |
| BAS Excluded | BAS Excluded | 0% | Not reported |
The BAS treatment column maps each tax code to the corresponding BAS field. The Australian Taxation Office's BAS form has G1 (total sales), G2 (export sales), G3 (other GST-free sales), G4 (input-taxed sales), and 1A (GST on sales) as the primary revenue fields (ATO BAS guidance, accessed 24 May 2026). The expense side uses G10 (capital purchases), G11 (non-capital purchases), and 1B (GST on purchases).
For an MSP whose customers are all Australian businesses paying GST-inclusive prices, almost every invoice line uses Standard GST. The other codes are for edge cases: an export customer (one-off training delivered to an NZ company), a residential lease (input-taxed), or a settlement entry that BAS does not report on.
UK VAT mapping
For UK-based MSPs, the Xero file has a different default tax-rate table. The Connect Zero mapping for a UK MSP looks like this.
| ConnectWise tax code | Xero tax rate | Rate | VAT return box |
|---|---|---|---|
| Standard VAT | 20% (VAT on Income) | 20% | Box 1, Box 6 |
| Reduced VAT | 5% (VAT on Income) | 5% | Box 1, Box 6 |
| Zero-Rated | Zero Rated Income | 0% | Box 6 |
| Exempt | Exempt Income | 0% | Not reported |
| Reverse Charge B2B Service | Reverse Charge Expenses (20%) | 20% in, 20% out | Box 1, Box 4, Box 6, Box 7 |
| EU Goods (post-Brexit) | EC Acquisitions (Zero Rated) | 0% | Box 9 |
The reverse-charge row is the one most likely to be set up wrong on a new install. For a UK MSP receiving a B2B service from a non-UK EU supplier (or vice versa under post-Brexit treatment), VAT is accounted for by the recipient, not the supplier. The Xero "Reverse Charge Expenses" tax rate produces the correct double-entry: VAT is owed (Box 1) and the same VAT is reclaimable (Box 4), netting to zero VAT impact but appearing on the return for compliance.
The 2026 UK VAT standard rate remains at 20 percent (HMRC VAT rate guidance, accessed 24 May 2026). The MTD (Making Tax Digital) requirement means UK MSPs file quarterly VAT returns through Xero's MTD-enabled submission flow.
US sales tax: the per-state complication
US sales tax is the messiest of the three jurisdictions because the rate depends on the customer's location, not the MSP's location. An MSP based in Texas selling to a customer in California applies the California sales tax rate, with a Texas-side reporting overlay. The "economic nexus" rules established by South Dakota v. Wayfair (2018) mean every MSP doing more than a threshold volume in any state has to register and collect sales tax in that state (Wayfair decision summary, accessed 24 May 2026).
The Connect Zero mapping for a US MSP looks materially different from the Australian or UK pattern. Each ConnectWise customer has a sales-tax-applicable flag and a destination state. The Xero side has one tax rate per state the MSP is registered in (typically 5 to 15 states for a mid-sized MSP). The mapping is conditional: for customers in registered states, apply the state-specific rate; for customers in non-registered states (where the MSP has no nexus), use a "No Tax" rate.
Many US MSPs offload the sales-tax computation to a dedicated service (Avalara, TaxJar) rather than maintaining 50 Xero tax rates. Connect Zero supports both patterns: native Xero rates for MSPs running their own tax table, or Avalara-API-driven rates for MSPs who want a managed solution.
Common mismapping scenarios and their fixes
The five mismapping scenarios we see most often, and the fix for each.
- Standard GST mapped to GST Free in Xero. All sales appear GST-free in the BAS. G1 (total sales) is correct but 1A (GST on sales) is zero. Fix: re-map Standard GST to "GST on Income 10%".
- Export sales mapped to BAS Excluded. The export sales do not appear in G2, which makes the BAS look like the MSP has no export revenue. Fix: re-map Export to "GST Free Exports".
- Reverse-charge VAT mapped to Standard VAT (UK). The MSP pays 20 percent VAT on the bill but cannot reclaim it because Box 4 is empty. Fix: re-map the relevant ConnectWise code to "Reverse Charge Expenses".
- US sales tax mapped to a fixed-rate code. Customer in a non-nexus state is charged sales tax inappropriately. Fix: implement the customer-location-conditional mapping pattern.
- Bill credit notes mapped to the same code as bills. The expense side of BAS or VAT return double-counts the GST credit. Fix: map credit notes to a "GST on Expenses" code with appropriate sign treatment.
Reconciliation at BAS / VAT return time
The right reconciliation pattern is to run the Xero tax-return wizard (BAS for Australian MSPs, VAT Return for UK MSPs, Sales Tax for US MSPs) and compare against the ConnectWise per-tax-code revenue report for the same period.
For an Australian MSP doing AUD 375k revenue in a quarter (one quarter of AUD 1.5 million annual), the expected BAS line items are: G1 around AUD 375k, 1A around AUD 34k (GST collected on sales), G3 small (a few AUD k for any GST-free exports), 1B around AUD 6k (GST paid on purchases). The variance between Xero BAS and ConnectWise per-tax-code report should be under AUD 50 for the quarter. Material variance (over AUD 200) means a mapping is wrong; walk back to the per-tax-code report to find which ConnectWise code is producing the variance.
For UK MSPs, the equivalent reconciliation is Xero VAT Return vs ConnectWise per-tax-code report. For US MSPs, the per-state Xero sales tax report vs the ConnectWise per-customer destination-state report.
Per the Australian MSPs and BAS guide, the quarterly reconciliation is the cheap insurance against a 12-month-late ATO query.
Pitfalls
- Treating the default mapping as production-ready. Connect Zero's defaults cover the standard Australian MSP shape. Multi-jurisdictional MSPs need to configure their own mapping. Verify before the first invoice goes live.
- Ignoring the asymmetry between income and expense codes. Xero has separate tax rates for "GST on Income" and "GST on Expenses". The sync needs to map the income-side ConnectWise codes to income-side Xero rates and likewise for expenses.
- Mapping all codes to one fallback rate. The BAS or VAT return is built from per-code revenue, so collapsing all codes hides errors until the tax office asks why.
- Forgetting the tax-code dimension on credit notes. A credit note reverses a sale; the tax code on the credit note must match the original sale, or the BAS shows a phantom GST liability.
- Cross-border MSPs running one Xero entity per jurisdiction without cross-jurisdiction tax routing. See the multi-currency guide for the entity-per-jurisdiction pattern; the tax mapping then flows per-entity, which is the right shape for cross-border MSPs.
Cross-border edge cases
Cross-border B2B services between Australian and UK or EU customers produce tax treatment that doesn't fit cleanly into either jurisdiction's standard categories. An Australian MSP selling managed services to a UK customer issues a GST-free export invoice (per ATO export sales rules) while the UK customer accounts for the VAT on the reverse-charge basis (per HMRC place-of-supply rules for B2B services, accessed 24 May 2026). The two sides of the transaction are correctly accounted for, but neither side's BAS or VAT return shows the transaction as taxable revenue at the standard rate.
The Connect Zero sync layer doesn't enforce this rule; the ConnectWise side has to know the customer is a UK B2B customer and apply the right tax code at invoice time. The sync passes the code through. The compliance responsibility lies with the MSP's accountant, who confirms the cross-border treatment at year-end.
For MSPs whose cross-border revenue is more than 10 percent of total revenue, we recommend a quarterly check with the accountant rather than just an annual one. Cross-border tax rules change occasionally (post-Brexit changes were the most recent material shift) and a quarterly check is the cheap insurance.
Where this fits
Tax mapping is one of the three foundational ConnectWise to Xero mappings, alongside tracking categories and the agreement-to-revenue-account mapping. Together they define every line item that lands in Xero.
For an end-to-end view of the sync architecture, see the Connect Zero product hub. For the broader vendor comparison, see the 2026 buyer's guide.
Frequently asked questions
How does ConnectWise represent tax codes?
ConnectWise PSA has a Tax Code table with one row per tax treatment (Standard GST, GST-Free, Input-Taxed, Export, and similar codes for other jurisdictions). Each invoice line is tagged with one tax code, which drives the tax computation at invoice approval.
How does Xero represent tax codes?
Xero has a Tax Rates table (Settings → Tax Rates) with one row per tax treatment. The default Australian Xero file ships with about 12 rates (GST on Income at 10 percent, GST on Expenses at 10 percent, GST Free Income, GST Free Expenses, BAS Excluded, and so on per Xero documentation, accessed 24 May 2026).
Does Connect Zero handle the mapping between ConnectWise tax codes and Xero tax rates?
Yes. The sync admin exposes a mapping table: one row per ConnectWise tax code, with a dropdown to select the matching Xero tax rate. The defaults cover Australian GST out of the box; international MSPs configure their own mappings.
What happens to a ConnectWise tax code that has no Xero mapping?
The invoice line lands in Xero with the BAS Excluded tax rate, which means it does not appear in the GST or VAT return. Connect Zero surfaces a warning on the sync run; the fix is to add the missing mapping in the admin.
About this article
Written by the Connect Zero team, an Australian-built ConnectWise to Xero sync sold by Auswide IT, an Australian MSP integration vendor based in Adelaide. We have configured tax mappings for Australian MSPs (BAS), UK MSPs (VAT, including reverse-charge), and US MSPs (multi-state sales tax with Avalara). Last updated 24 May 2026.
