Planning tool · 50% FYA deadline

FYA deadline calendar — month-by-month planning

A working calendar for capturing the 50% First Year Allowance before the 31 March 2026 deadline. Month-by-month order placement guidance by project size, expected lead times, and what to do if you miss the window.

Lead-time assumptions: 12–48 weeks from contract execution to commissioning depending on project size, with DNO process and procurement as the primary constraints. Verify against your specific site before committing to commissioning timing.

The deadline mechanics

The 50% First Year Allowance applies to qualifying capital expenditure on commercial solar PV incurred before 31 March 2026 (unless extended in a future Budget). For capital allowance purposes, expenditure is "incurred" on the date the asset is brought into use — typically when commissioned and producing electricity, evidenced by G99 commissioning and meter records.

For a project to capture FYA, commissioning must complete by 31 March 2026 (or by your accounting year-end if it falls before that date). Working backwards through the typical lead times tells you when orders need to be placed.

Month-by-month planning calendar

May 2025

305 days to deadline

All sizes — comfortable timing on most projects

Begin discovery and design for projects targeting end-March 2026 commissioning.
Order placement before end-Q3 2025 safe for 100kW–1MW projects.
DNO process can begin in parallel for larger projects.

June 2025

274 days to deadline

All sizes

Comfortable timing — full design and DNO process feasible.
Order placement Q3 still on track for end-March 2026 commissioning.

July 2025

244 days to deadline

All sizes — last comfortable window for 1MW+

1 MW+ projects need orders placed by end-July to safely commission by end-March 2026.
DNO connection studies for larger projects must be in progress.

August 2025

213 days to deadline

Below 500 kWp — comfortable; above 500 kWp — tight

1 MW+ projects: order placement now is at the limit. Rapid progression required from here.
500 kWp projects: order by end-August for comfortable timing.
100–250 kWp: still substantial slack.

September 2025

183 days to deadline

Below 500 kWp; 1MW+ now risky

1 MW+ projects: order placement now produces tight DNO + procurement + construction sequence. Consider deferring rather than accepting risk.
500 kWp: comfortable for now.
Discovery work for end-2025 / early-2026 year-ends should kick off if not already in progress.

October 2025

152 days to deadline

300–500 kWp; below 300 kWp comfortable

500 kWp+ projects need order placement now to safely commission by end-March 2026.
300 kWp: still feasible with smart sequencing.
Below 300 kWp: comfortable.

November 2025

122 days to deadline

Below 300 kWp

Last reliable window for 300 kWp projects — order now to commission by end-March 2026.
Below 200 kWp: comfortable timing.
Above 300 kWp: defer to post-deadline scenario unless DNO position is already established.

December 2025

92 days to deadline

Below 200 kWp

200 kWp projects feasible only with established DNO position and pre-procured equipment.
Below 100 kWp: realistic for end-March commissioning.
Above 200 kWp: post-deadline timing now realistic — model both FYA and post-FYA cases.

January 2026

60 days to deadline

Below 100 kWp

100 kWp+ projects: post-deadline timing now expected. Recommend deferring for clean post-deadline launch with predictable timing.
Sub-50 kWp: realistic with simple installation.

February 2026

30 days to deadline

Sub-50 kWp only

Only sub-50 kWp simple installations realistic for end-March 2026 capture.
Above 50 kWp: clean defer to post-deadline. The post-deadline IRR is still 12–15% on profitable trading companies.

March 2026

1 days to deadline

Cliff-edge — only commissioned-by-31-March projects qualify

No new orders capture FYA — equipment must be commissioned and producing electricity by 31 March 2026.
Final commissioning push on projects already in late-stage construction.

April 2026 onwards

0 days to deadline

Post-deadline — special-rate pool only

No FYA available. All qualifying capex enters special-rate pool at 6% writing-down allowance.
Lifetime tax value drops from 17–19% of capex (FYA route) to ~9% (special-rate pool only).
Project IRR drops by 2–3 percentage points but most projects still attractive on profitable trading companies.
Re-engage if FYA extended in subsequent Budget; otherwise plan around AIA where headroom available.

Lead-time breakdown

Total project lead time varies 20–48 weeks depending on size. The components:

Discovery and design: 4–8 weeks (site survey, structural review, demand modelling, financial structuring). Add 4 weeks for finance package execution.
DNO process: 6–24 weeks depending on system size. Above 200 kWp triggers G99 connection studies; above 500 kWp often triggers reinforcement studies adding further weeks. DNO can become the binding constraint; don't assume parallel processing.
Procurement: 8–14 weeks for modules and inverters from order to delivery. Tier-1 module suppliers typically 10 weeks; central inverter manufacturers can run 14 weeks.
Construction: 1–6 weeks depending on system size and access complexity. Larger projects sequence across multiple roof sections.
Commissioning: 1–4 weeks. G99 commissioning requires DNO inspection slot — can take 2–6 weeks to schedule on busy DNO patches.

Recommended actions by accounting year-end

Year-end	FYA Window	Recommended action
Before 30 Sep 2025	Already missed for current year; available for following year	Plan toward the next financial year capturing FYA in early-2026 commissioning
Oct–Dec 2025	Full window — orders placed by July 2025 safely capture FYA	Push completion now if not already in motion. Above 500 kWp: order by August 2025 latest
Jan–Mar 2026	Tight window — orders placed by Sep 2025 most reliable	Prioritise smaller projects (sub-300 kWp). Larger projects: model post-FYA case as fallback
After 31 Mar 2026	Post-deadline — special-rate pool only	Plan around AIA where headroom available; otherwise accept ~9% lifetime tax saving via SRP

FYA planning FAQs

When does HMRC consider expenditure "incurred" for FYA purposes?

Expenditure is generally treated as "incurred" on the date there is an unconditional obligation to pay. For commercial solar, this typically means the date the asset is brought into use — commissioned and producing electricity (with G99 commissioning evidence and meter records). Order date and payment date don't determine FYA timing; commissioning date does.

What if we miss the 31 March 2026 deadline?

The qualifying capex enters the special-rate pool at 6% writing-down allowance. Net present value of the lost FYA: approximately 8–10% of capex at typical discount rates and the 25% main rate. On a £200,000 system that's £16,000–£20,000 of present-value tax saving lost. Most projects with strong fundamentals still produce 12–15% IRR even without FYA.

Could the FYA be extended in the Budget?

Possible but uncertain. Each successive extension has been short. The Treasury continues to treat the FYA as a time-limited stimulus rather than a permanent feature. Plan around the deadline, not on the assumption it extends again. Budget announcement timing typically October — too late for projects already mid-construction.

Should we accept higher project risk to capture FYA?

Generally no. Year-end FYA capture is meaningful but rarely project-critical. A rushed installation with insufficient DNO time, structural assessment, or commissioning risk often produces problems that exceed the FYA value. For Q4 2025 enquiries on larger projects, we typically recommend modelling both FYA and post-FYA scenarios. If post-FYA IRR is still above hurdle rate, the project doesn't depend on FYA timing.

Can AIA fill the gap if we miss FYA?

Where AIA headroom is available for the period, yes — and AIA is more valuable than FYA where it applies. AIA gives 100% deduction in year one on the first £1m of qualifying capital expenditure per accounting period. The constraint is that AIA is shared across all qualifying capital spend in the period. If your business has other capital investment (vehicles, plant, fit-out), AIA headroom may already be partly committed. Confirm with your accountant.

Map your accounting year-end against project timing

Our advisory engagement maps year-end FYA capture timing against your specific project size, demand profile, and DNO position. We model both FYA-capture and post-deadline scenarios so you can make an informed timing decision.

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