ISA tax-year allowance changes

According to His Majesty's Revenue and Customs ISA Managers Guidance reviewed in August 2026 against our methodology, the overall adult ISA allowance stands at 20,000 GBP for the 2026/27 tax year.

PlainISA stores HMRC-published subscription limits by tax year and computes the arithmetic between consecutive years. Gov.uk tables show each year's limit; this page surfaces what moved (and what stayed flat) without inventing movement.

Latest pair: 2025/26 → 2026/27

No subscription-limit deltas between 2025/26 and 2026/27. Adult overall, Junior, and Lifetime sub-limit are unchanged in the stored history for this pair.

Unchanged this pair

  • Adult ISA overall subscription limit: £20,000 (2025/26 and 2026/27)
  • Junior ISA subscription limit: £9,000 (2025/26 and 2026/27)
  • Lifetime ISA annual subscription sub-limit: £4,000 (2025/26 and 2026/27)

Historic step-changes

Only non-zero year-over-year moves. The largest recent Junior jump is 2019/20 → 2020/21; the adult overall last moved 2016/17 → 2017/18.

  1. 2019/20 → 2020/21

    Junior ISA subscription limit rose from £4,368 to £9,000 between the 2019/20 and 2020/21 tax years (+£4,632).

  2. 2018/19 → 2019/20

    Junior ISA subscription limit rose from £4,260 to £4,368 between the 2018/19 and 2019/20 tax years (+£108).

  3. 2017/18 → 2018/19

    Junior ISA subscription limit rose from £4,128 to £4,260 between the 2017/18 and 2018/19 tax years (+£132).

  4. 2016/17 → 2017/18

    Adult ISA overall subscription limit rose from £15,240 to £20,000 between the 2016/17 and 2017/18 tax years (+£4,760).

  5. 2016/17 → 2017/18

    Junior ISA subscription limit rose from £4,080 to £4,128 between the 2016/17 and 2017/18 tax years (+£48).

  6. 2014/15 → 2015/16

    Adult ISA overall subscription limit rose from £15,000 to £15,240 between the 2014/15 and 2015/16 tax years (+£240).

  7. 2014/15 → 2015/16

    Junior ISA subscription limit rose from £4,000 to £4,080 between the 2014/15 and 2015/16 tax years (+£80).

Download full tax-year history CSV · narrative timeline also on History of UK ISAs.

Source: HMRC / GOV.UK Annual savings statistics (subscription limits) Adult and Junior ISA subscription limits · 2026/27 2026/27 current-year figures also checked against live gov.uk ISA guidance. Deltas are arithmetic between stored tax-year rows only.

Every delta on this page is the difference between two rows in our isa_allowance_history table, seeded from HMRC Annual savings statistics and live gov.uk ISA guidance for the current tax year. Flat pairs are reported as unchanged; we do not invent movement. Read our editorial standards and corrections policy, the methodology behind these numbers, or report a data error.

Primary statutory sources: gov.uk’s Individual Savings Accounts guidance and HMRC’s ISA Managers Guidance Notes. Historical context is checked against HMRC’s annual ISA statistics.

PlainISA publishes ISA reference data and projection tools for information only. It is not financial advice and not a personal recommendation, projections are illustrations rather than forecasts, and tax rules and allowances change, so check the current position on gov.uk or with an FCA-authorised adviser before you act. Appropriate use.