Tax-Efficient Investment Order Calculator UK 2026

Q: What is the optimal investment order in the UK?

The general optimal order for UK investors is: (1) Employer pension contributions up to the employer match — this is free money. (2) Pay off high-interest debt (above 5–6%). (3) Build an emergency fund (3–6 months expenses in cash). (4) Max your ISA (£20,000/year). (5) Max your SIPP contributions (up to £60,000 or 100% of earnings). (6) Any surplus goes into a General Investment Account (GIA).

Calculate the optimal order to fill your tax wrappers — ISA, SIPP, and General Investment Account (GIA). Maximise after-tax returns by using the right wrapper first.

Calculate Your Optimal Investment Order

Frequently Asked Questions

ISA vs SIPP — which is better in the UK for 2026?

It depends on your tax situation. A SIPP offers upfront tax relief (20–45%) making it powerful for higher-rate taxpayers, but money is locked until age 57. An ISA offers no upfront relief but all withdrawals are completely tax-free and accessible anytime. Most advisers recommend using both.

What is the optimal investment order in the UK?

The general optimal order: (1) Employer pension match — free money. (2) Pay off high-interest debt. (3) Emergency fund 3–6 months. (4) Max ISA (£20,000/year). (5) Max SIPP (up to £60,000). (6) Surplus into GIA.

Should I use an ISA or pension first in the UK?

Higher-rate (40%) and additional-rate (45%) taxpayers should generally prioritise the SIPP first because the upfront tax relief is very valuable. Basic-rate (20%) taxpayers often benefit more from the ISA first due to accessibility and flexibility.

Can I have both an ISA and a SIPP in the UK?

Yes, absolutely. You can hold and contribute to both an ISA and a SIPP in the same tax year. The annual ISA allowance is £20,000 and the pension annual allowance is £60,000 (2025/26). Using both is the recommended approach for most UK savers.

What is the tax difference between a GIA and an ISA in the UK?

Inside an ISA, all growth, dividends and interest are completely tax-free. In a GIA, you pay Capital Gains Tax on gains above £3,000 at 18%/24%, and dividends above £500 are taxed at 8.75–39.35%. Use a GIA only after maxing your ISA and SIPP.