Terms & Conditions

1. Agreement

These Terms and Conditions ("Terms") govern your use of OneSixth ("the Service"), operated by Option To VAT Limited (company number 15668306; VAT registration number 523 3658 94; ICO registration number ZC197273), a company registered in England & Wales with registered office at 10 Albemarle Street, Clitheroe, BB7 2EA, United Kingdom ("we", "us", "our"). By accessing or using the Service, you agree to be bound by these Terms. If you do not agree, you must not use the Service.

2. Service Description

OneSixth provides modules for margin VAT, TOMS and partial exemption compliance via integration with Xero, QuickBooks Online, Sage and FreeAgent:

Margin VAT — Calculate and post margin VAT adjustments for second-hand goods, motor vehicles, art, antiques, collectors' items, horses and global accounting under the VAT margin scheme.
TOMS (Tour Operators Margin Scheme) — Manage quarterly provisional VAT calculations and annual adjustments under the Simplified Method (VAT Notice 709/5).
Partial Exemption — Calculate recoverable input VAT, de minimis tests and the annual adjustment under the standard method (VAT Notice 706).

The Service allows firms to connect multiple organisations across your supported accounting platforms and manage VAT adjustments from a single dashboard.

3. Eligibility

The Service is intended for use by accounting professionals and businesses registered in the United Kingdom. You must be at least 18 years old and have the authority to bind the organisation you represent.

4. User Accounts

You are responsible for maintaining the confidentiality of your account credentials
You must provide accurate and complete information when creating your account
You are responsible for all activity under your account
You must notify us immediately of any unauthorised use

5. Accounting platform integration

By connecting your accounting platform (Xero, QuickBooks Online, Sage or FreeAgent), you authorise us to access your accounting data as necessary to provide the Service. You remain responsible for ensuring the accuracy of data within your connected platform and the correctness of any journal entries posted.

For TOMS users: the Service implements the Simplified Method only as described in HMRC VAT Notice 709/5. You are responsible for determining whether the Simplified Method is appropriate for your business.

6. HMRC Making Tax Digital connection

If you connect an HMRC Making Tax Digital VAT account, you authorise us to read VAT obligations, returns, liabilities and payments for that business, on a read-only basis.
OneSixth does not submit VAT returns to HMRC. Returns are filed through your MTD-compatible accounting software, and you remain responsible for the accuracy and timely filing of returns and payments.
You must have the business's authority (as the taxpayer or its authorised agent) before connecting.
We send fraud-prevention data to HMRC as required by law (see our Privacy Policy).
HMRC's services are outside our control; we are not liable for HMRC downtime, errors or changes to HMRC's APIs.

7. Acceptable Use

You agree not to:

Use the Service for any unlawful purpose
Attempt to gain unauthorised access to any part of the Service
Interfere with or disrupt the Service or its infrastructure
Reverse engineer, decompile, or disassemble any part of the Service
Use the Service to process data you are not authorised to access

8. Intellectual Property

All intellectual property rights in the Service belong to Option To VAT Limited or our licensors. You are granted a limited, non-exclusive, non-transferable licence to use the Service in accordance with these Terms.

9. Disclaimer

The Service is provided "as is" without warranties of any kind. While we strive for accuracy, we do not guarantee that VAT calculations will be error-free. You remain solely responsible for verifying all journal entries and ensuring compliance with HMRC requirements. For TOMS calculations, refer to HMRC VAT Notice 709/5. For margin scheme records, see gov.uk/vat-margin-schemes/keeping-records.

10. Limitation of Liability

To the maximum extent permitted by UK law, our total liability to you shall not exceed the fees paid by you in the 12 months preceding the claim. We shall not be liable for any indirect, incidental, consequential, or special damages.

11. Service availability

We aim for 99.5% monthly availability of the Service, excluding scheduled maintenance and events outside our reasonable control. We do not offer service credits at this time. Live service status and incidents are published at status.onesixth.app. Product updates are published on our changelog.

12. Termination & data export

Either party may terminate the subscription in accordance with the chosen billing cycle. We may suspend or terminate access immediately for material breach of these Terms. After termination, you may request an export of your data for 30 days; thereafter we will delete or anonymise customer personal data, save where retention is required by law (notably the 6-year HMRC record-keeping obligation for VAT-relevant data).

13. Data protection

Where we process personal data on your behalf, we do so as your processor under our Data Processing Agreement (download PDF), which is incorporated into these Terms by reference. Our processing of your own administrative data is governed by our Privacy Policy.

14. Modifications to these Terms

We may update these Terms from time to time. For material changes, we will give at least 30 days' notice by email or in-app notification before they take effect. Continued use of the Service after the effective date constitutes acceptance.

15. Governing Law

These Terms are governed by the laws of England and Wales. Any disputes shall be subject to the exclusive jurisdiction of the courts of England and Wales.

16. Contact

For questions about these Terms, contact us at support@onesixth.app. For billing or invoice queries, email billing@onesixth.app.