PolicyEngine UK

Claude Code with the PolicyEngine plugin.

We just launched a plugin that brings PolicyEngine to Claude.

Describe any tax or benefit reform in plain English. Claude runs a full microsimulation using our open-source model — 700+ variables, 1,200+ parameters, NI to UC.

No code required.

policyengine.org/uk/claude-pl...

Our new dashboard analyses the Scottish Budget 2026-27:

📊 £64m cost in 2026-27 → £196m revenue by 2030-31
📈 Threshold uplifts, SCP expansion, rate freezes
🏠 Household calculator to see your impact

Explore: policyengine.org/uk/scottish-budget-2026-27

2025 was a landmark year for PolicyEngine UK.

1,010 local areas modelled
38 reports & trainings published
9 Autumn Budget provisions analysed

From the Local Areas Dashboard to GiveCalc UK—here's what we accomplished.

Explore our interactive year in review: policyengine.org/uk/2025-year-in-review

Our complete analysis of the UK Autumn Budget 2025 is now live.

New interactive dashboard lets you explore how all 9 provisions interact—by income decile, constituency, and year through 2030-31.

Explore: policyengine.org/uk/autumn-budget-2025

Free at givecalc.org

(By the way, PolicyEngine is a registered charity)

Launching GiveCalc for UK taxpayers 🇬🇧

Calculate your Gift Aid tax relief in seconds. Enter your income and donation — see exactly how much you save.

✓ Higher rate relief (40%/45%)
✓ Scottish income tax rates
✓ Personal Allowance taper effects

The UK's first rail fare freeze in 30 years will cost £145m in 2026-27, rising to £775m cumulative by 2030-31.

Read our new report for more on the revenue and distributional implications: www.policyengine.org/uk/research/...

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

See our full analysis for more: www.policyengine.org/uk/research/...

Revenue and distributional impacts vary by behavioural assumptions. Interactive charts let you explore all scenarios.

Key findings:
- 4.9 million workers use salary sacrifice for pensions
- 3.3 million (68%) contribute above £2,000
- Total salary sacrifice contributions: £22.7bn

NEW: How will the £2,000 cap on salary sacrifice pension contributions affect UK workers?

We modelled four behavioural scenarios to show how revenue and distributional impacts vary.

The new high value council tax surcharge will raise £400m/year from £2m+ properties.

Top 10 constituencies = 35% of revenue. Cities of London & Westminster alone: 10%.

Explore our latest Autumn Budget analysis and interactive: www.policyengine.org/uk/research/...

The OBR revised up its inflation and earnings forecasts in the November 2025 Autumn Budget. We compare the projections and explain what changed for PolicyEngine users.

policyengine.org/uk/research/...

NEW: We've modelled the Autumn Budget fuel duty freeze

Key findings for 2026-27:
- £2.8bn revenue cost
- 46.7% of people gain
- Lowest decile: +0.30% income
- Highest decile: +0.11% income
- 0.18% reduction in inequality

www.policyengine.org/uk/research/...

Here's how these four landed in the Autumn Budget:

Repealing two-child limit ✅
Increasing income tax by 2p ❌
Reducing NI by 2p ❌
Freezing income tax thresholds ✅
Adjusting VAT thresholds ❌
Surcharge on high-value properties ✅

Stay tuned for analysis of other provisions.

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

We'll be releasing an Autumn Budget Dashboard this afternoon with real-time analysis of announced policies.

Follow along at policyengine.org

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

Reported: levy on homes over £2m.

We mapped 2024 property sales:
• 3 central London seats: 21% of high-value sales
• London overall: 45-46%
• Top 10 seats (all London/commuter belt): 36%

policyengine.org/uk/research/...

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

The Telegraph reported a potential VAT threshold increase.

Our analysis:
• £100k threshold: -£371m, exempts ~48,000 firms
• £70k threshold: +£642m, adds 109,000 firms

Full analysis: policyengine.org/uk/research/...

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

Reported: +2pp income tax, -2pp NI, extended freezes

Our findings:
• +£6.9bn revenue
• Under £58k: gain
• Over £58k: lose up to £1,748/year
• Pensioners pay only the IT hike

policyengine.org/uk/research/...

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

The two-child benefit limit restricts Universal Credit to the first two children.

Our analysis of abolishing it:
• Cost: £2.5bn/year
• 300,000 children lifted out of poverty
• Child poverty rate falls 1.2pp

Full analysis: policyengine.org/uk/research/...

Chancellor Reeves delivers the Autumn Budget at 12:30 PM.

Here's our analysis of 4 policies the government may announce:

🧵👇

Where would a mansion tax hit hardest?

We mapped 2024 property sales above £2m by constituency. Three central London seats account for 21% of all high-value sales nationwide.

Explore the interactive map and toggle between thresholds: policyengine.org/uk/research/uk-mansion-tax-autumn-budget

PolicyEngine Free, open-source tools to understand tax and benefit policies. Calculate your taxes and benefits, or analyze policy reforms.

NEW: The Times reported Chancellor Reeves considered raising income tax by 2pp while cutting NI by 2pp.

We modeled the package. In 2026-27: +£18.6bn from income tax, -£11.7bn from NI cut. Net £6.9bn.

By 2029-30, with the threshold freeze extension: £15.4bn. www.policyengine.org/uk/research/...

We're at capacity for "PolicyEngine 2.0 and the Future of Public Policy Analysis" today at Central Hall Westminster!

Excited to welcome researchers and policymakers for a day of demos, applications, and discussions.

Here's what we have planned 👇

BREAKING: PolicyEngine's microsimulation model projects a surge in candy consumption in the coming hours.

Happy Halloween! 🎃

Update: We have moved this event to Monday, 3rd November. Same time and place, even more speakers and technology for evidence-based policymaking.

Register here: www.eventbrite.co.uk/e/policyengi...

Economic policy happy hour · Luma Drinks and discussion for the UK economic policy community. PolicyEngine is hosting an informal happy hour for economists, researchers, and policy analysts…

Economic policy drinks tomorrow in London 🍺

Thursday 6-8pm at The Sherlock Holmes (Northumberland St, near Embankment)

Light bites + first round on PolicyEngine. Come meet economists & policy analysts working on UK tax/benefits/public finance.
luma.com/oz1qt2ec

PolicyEngine 2.0 and the future of public policy analysis Discover PolicyEngine's Latest Innovations in Evidence-Based Policy Analysis.

📍 London | 25th September | 12:00-18:00 | Central Hall Westminster

PolicyEngine 2.0 and the future of public policy analysis

Join us for live demos, breakthrough research presentations, and networking with leaders shaping evidence-based policymaking.
www.eventbrite.co.uk/e/policyengi...

How changing the VAT threshold affects UK revenues | PolicyEngine UK PolicyEngine's new firm microsimulation model estimates revenue and business impacts of VAT thresholds from £70,000 to £120,000.

We've built synthetic firm microdata calibrated to ONS and HMRC statistics to model these impacts.

The analysis also shows how many businesses would enter or exit VAT at different thresholds.

Full analysis: policyengine.org/uk/research/...

How would changing the VAT threshold from £90k affect revenues?

Our new firm microsimulation model shows:
• £70k threshold: +£640m revenue
• £100k threshold: -£370m revenue
• £120k threshold: -£1.1bn revenue

All estimates for 2026-27.