GoSimpleTax partner guide. We earn commission on qualifying purchases made through this link.
FiscalFox turns your broker transactions into investment tax figures and supporting reports. GoSimpleTax is a separate service for completing and submitting your full Self Assessment return to HMRC. If you choose to file with GoSimpleTax, you can take your FiscalFox reports with you and enter the relevant figures there.
This is a manual handoff: opening GoSimpleTax does not send it your transactions, reports or personal details. Your FiscalFox report pack remains available to download, whether you use GoSimpleTax, another filing service or an accountant.
Prepare the right year's reports
In FiscalFox, select the tax year you are filing and download your report pack. Keep that year's files together while completing your return, rather than combining totals from different years. The individual report pack includes your SA108 figures, gain and loss computations and Section 104 pool working.
Start with the SA108 summary for the capital gains sections. The detailed computations show how the gains and losses were calculated, while the pool working records the acquisition costs carried between disposals. Keep the supporting PDFs with your records and available if you need to attach an explanation to your return.
If your FiscalFox result identifies specific items to review, use that year's review to resolve them before treating the affected figures as final. A link to filing software does not change which transactions or income are included in your calculation.
Enter your capital gains in GoSimpleTax
GoSimpleTax's capital gains help guide explains how to open your return, choose + New Page and add the Capital Gains (SA108) page. Use the FiscalFox summary for the same tax year as your reference while completing the relevant sections.
Keep the categories in your SA108 summary separate when entering the figures. Your total estimated tax is not a substitute for the proceeds, costs, gains and losses requested in the capital gains pages. Our SA108 guide explains what those figures describe.
For larger portfolios, GoSimpleTax's published guidance describes entering combined totals with an explanation when its individual disposal limit is exceeded, and attaching a PDF of the detailed calculations. Follow its current instructions for your return and use your FiscalFox computations as supporting evidence.
Before submitting, use GoSimpleTax's return report to check your entries against the FiscalFox summary and supporting files. GoSimpleTax's screens are separate from FiscalFox's guide to HMRC's own online service; follow the instructions for the service you are actually using.
Complete the rest of your return
Your investment calculations are one part of your Self Assessment. Gather the records for your other income and any other sections you need to complete. Where FiscalFox provides investment income figures, keep their labels and tax year alongside the capital gains working so you enter each item in the appropriate part of the return.
The report pack is supporting working, rather than a submitted tax return. You complete and submit the return in GoSimpleTax. For questions about its screens, attachments or submission, use GoSimpleTax's help centre; for questions about a FiscalFox calculation or download, contact FiscalFox.
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Partner offer
Save 15% with GoSimpleTax
Sign up to receive your discount code by email, then apply it at checkout.
Use the link below to visit GoSimpleTax from FiscalFox. Keep the email containing your code until checkout; the discount is applied when you enter the code.
Continue to GoSimpleTax (opens in a new tab)We earn commission on qualifying purchases made through this link.
Practical questions
Are my figures transferred automatically?
No. You enter the relevant figures in GoSimpleTax yourself and can use your downloaded FiscalFox reports to support them. Following our link does not upload your data or give GoSimpleTax access to your FiscalFox account.
Do I have to use GoSimpleTax?
No. Your report pack can also support another filing route or an accountant's work. Purchased individual reports include an option to send the workings to your accountant. The existing guide in FiscalFox also explains using your figures with HMRC's online return.
What if my discount email does not arrive?
Check your spam folder and the email address used to sign up. If the code is still missing or is not accepted at checkout, contact GoSimpleTax through its help centre before paying. FiscalFox does not issue the code.
Does purchasing a FiscalFox report file my return?
No. It gives you the calculation and supporting report files. Completing and submitting your return is a separate step, whichever filing service you choose.
Sources and offer information
Workflow checked on 3 November 2026 against GoSimpleTax's published capital gains instructions. The 15% offer and email-code process were supplied by GoSimpleTax for FiscalFox customers. For the underlying capital gains form, see the official SA108 form and notes.
Official UK tax references
This guide is checked against published GOV.UK and HMRC material. FiscalFox is a calculation tool, not personal tax advice; review unusual transactions with a qualified adviser.