Stable Numbers
ISA Allowance Splitter
Enter your monthly saving budget and get a clean split across Cash ISA, Stocks & Shares ISA and Lifetime ISA. The tool respects the £20,000 ISA limit, the £4,000 LISA cap, and the months left to 5 April. You can pick a strategy or set your own weights. Share your setup and export the plan.
Tax year runs 6 April to 5 April. Auto fills from today.
If unsure, leave at £20,000 then trim later.
Checks LISA eligibility (18 to 49 inclusive).
Lifetime ISA preference
Prioritise LISA up to its £4,000 annual cap if eligible. The tool computes a monthly cap based on months left.
Leave blank to auto cap at min(£333.33, remaining ÷ months).
LISA funding allowed from 18 until your 50th birthday.
Strategy for the remainder
After the LISA slice, split the rest between Cash ISA and Stocks & Shares ISA.
Cash, S&S
Heads up: your LISA slice would overrun the remaining LISA allowance by . The tool caps monthly LISA automatically. Adjust your manual override if set.
Warning: this plan would exceed your remaining overall ISA allowance by . Lower the budget or weights, or confirm your remaining figure.
About this tool
This planner gives you a practical split across ISA types for the months left in the tax year. If you are eligible and choose to prioritise a Lifetime ISA, it allocates a monthly slice to LISA that fits within the £4,000 cap for the year. The cap is spread evenly using months left, or you can enter a manual monthly figure. The remainder is then split between a Cash ISA and a Stocks & Shares ISA using a preset strategy or your own custom weight.
The cards show projected totals to 5 April and highlight any risk of breaching either the overall ISA allowance or the LISA cap. It is a planning guide, not advice. Actual products have their own rules, fees and processes, and market values can fall as well as rise. If you are running close to yearly limits, leave a sensible buffer for provider timing and rounding.
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