SA100 Tool

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SA100-s Tool | Client Profile V0.3

UK Self Assessment — SA100-s Tool

Client Profile · Tax year 2025/26 · England · Version 0.3

Welcome to the SA100 Tool

Choose how you would like to continue.

Guest

Guest mode — no automatic saving

1. Client profile

Enter your details in one place. You can leave identifiers blank while preparing a draft. Fields marked * are required for a final return, not for this profile draft.

Tax year

Title

Date of birth

First name *

Last name *

Unique Taxpayer Reference (UTR)

National Insurance number

Email address (optional)

Phone number (optional)

Home address

Address line 1

Address line 2

Town / city

Postcode

Country

Tax residence and scope

Were you UK tax resident throughout the whole tax year?

Did you have any income from outside the UK?

UK tax jurisdiction

How would you like to complete your return?

Income sources

Choose an income type from the list and click Add. Only selected income types will be available in future return sections.

Income type

No income types selected.

MTD Tool records

Import annual records from MTD ToolComing soon

HMRC credentials

Show HMRC connection (future feature)

HMRC authentication is not available in this version. Do not enter your Government Gateway username, password or access codes here. The future connection must use HMRC's authorised sign-in flow rather than collecting your password in this form.

2. Profile check

Check whether the information suggests a full self-service route or an accountant-assisted draft. This is an initial scope check, not a final tax residence determination.

Complete the profile and select Check profile.

In guest mode, your information is not saved automatically. To keep a copy, select Download profile (JSON) and store the file securely.

SA100 Tool

Welcome to the SA100 Tool

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1. Client profile

Home address

Tax residence and scope

Income sources

MTD Tool records

HMRC credentials

2. Profile check

Advanced settings