The bottom line
At a £500/day contract over 220 days in 2026/27, the difference between inside and outside IR35 is about £3,610/year: outside nets ~£69,129 via Ltd, inside nets ~£65,519 via umbrella.
That's the headline number. The fuller story is that the financial gap shrinks at higher day rates (PA-taper + additional-rate dividend tax catch up), the qualitative differences (admin, IR35 risk, pension efficiency, mortgage treatment) often matter more than the £, and you don't actually choose your status, your engagement and your client do.
What inside / outside actually mean
IR35 is the UK tax rule that asks whether a contract is genuine self-employment or disguised employment. Inside IR35 means HMRC (or your engager, under the off-payroll rules) considers the engagement to be employment in substance, even though you invoice through a Ltd or umbrella. Outside IR35 means it's genuine self-employment.
The distinction is determined by three principal tests (control, substitution, mutuality of obligation) plus a handful of supporting factors. For the full breakdown of how status is determined, see our what is IR35? guide. For the rest of this page we'll focus on what actually CHANGES for the contractor in each case.
Practically: inside IR35 almost always means working through an umbrella company on PAYE. Outside IR35 usually means working through your own Ltd company taking salary + dividends.
The financial difference at typical day rates
The £/year gap between inside and outside isn't flat , it depends on your day rate, your number of working days, and your other tax circumstances. A few worked examples at 220 days, 2026/27, no student loan, rUK, standard inputs:
| Day rate | Inside (umbrella) net | Outside (Ltd) net | Gap |
|---|---|---|---|
| £300 | ~£44,200 | ~£46,150 | +£1,950 |
| £500 | ~£65,519 | ~£69,129 | +£3,610 |
| £700 | ~£85,200 | ~£87,800 | +£2,600 |
| £900 | ~£103,400 | ~£105,200 | +£1,800 |
Approximate figures, single applicant, no SL, rUK, £12,570 director salary. Ltd assumes max-dividend distribution and £1,200 accountancy + £500 other expenses.
Two patterns to notice. The gap is widest in the middle band(£400–£600/day): the dividend rate advantage compounds and you're comfortably below the £100k PA-taper. The gap shrinks at very high day rates: PA fully tapers above £125,140 of total income, additional-rate dividend tax (39.35%) catches up with PAYE's 45% additional rate, and the Ltd advantage compresses to £1,500–£2,500.
The gap is also narrower when you factor in pension. Both routes have efficient pension options; via umbrella the salary-sacrifice mechanism captures both employee and employer NI savings, while via Ltd the company makes employer contributions directly with full corporation tax relief. For a contractor doing £20,000+/year of pension contributions, the routes are often within £1,500/year of each other.
Compare at your day rate
Run the side-by-side at your specifics. The calculator handles the full money flow: umbrella margin and employer NI on the umbrella side; corporation tax (with marginal relief), salary, and dividends on the Ltd side.
At £500/day × 220 days
Limited company wins by £3,610 a year
Ltd nets £69,129 (62.8% of revenue). Umbrella nets £65,519 (59.6% of the assignment).
Umbrella (inside IR35)
£65,519
£5,460/month · 59.6% retained
Show umbrella breakdown
| Assignment | £110,000.00 |
|---|---|
| Umbrella margin | −£1,300.00 |
| Employer NI | −£13,464.29 |
| Apprenticeship Levy | −£473.81 |
| Income tax | −£25,336.76 |
| Employee NI | −£3,905.84 |
| Net | £65,519.30 |
Limited company (outside IR35)
£69,129
£5,761/month · 62.8% retained
Show Ltd breakdown
| Revenue | £110,000.00 |
|---|---|
| Director salary | −£12,570.00 |
| Employer NI on salary | −£1,135.50 |
| Accountancy fees | −£1,200.00 |
| Other expenses | −£500.00 |
| Pre-tax profit | £94,594.50 |
| Corporation taxEffective 22.5% | −£21,317.54 |
| Distributable as dividends | £73,276.96 |
| Income tax on salary | −£0.00 |
| Employee NI on salary | −£0.00 |
| Dividend tax | −£16,717.76 |
| Net (salary + dividends after tax) | £69,129.20 |
10-row side-by-side comparison
The financial number is one input. The qualitative dimensions matter just as much for the right answer at your specific situation.
| Dimension | Inside (umbrella) | Outside (Ltd) |
|---|---|---|
| Tax efficiency | Standard PAYE; no dividend access | Salary + dividends; lower effective rate at most rates |
| Admin burden | Effectively zero, payroll handled by umbrella | ~30-50 hours/year (bookkeeping, CT return, SA, statutory filings) |
| IR35 risk cost | Zero, engager bears the determination liability | £200-£500/yr IR35 insurance + non-insurable risk if determination wrong |
| Cost of running the vehicle | £15-£30/wk umbrella margin (~£1,000/yr) | £1,000-£1,500/yr accountancy + £200 PI insurance |
| Pension efficiency | SS captures EE + ER NI savings, very efficient | Employer pension via Ltd: CT relief, no personal tax, slightly better |
| Holiday / sick / parental | Statutory minimums via umbrella employer | None, must self-fund time off |
| Mortgage treatment | PAYE payslips, standard high-street treatment | 2 years of salary+dividends; specialist lenders use net profit |
| Income volatility buffer | Short contract gaps painful, no cash retained | Can retain profit in company; smooths years |
| Engagement length flexibility | Excellent, 1-week assignments fine | Setup overhead favours longer (3+ month) engagements |
| Exit / wind-down | Just stop the assignment, clean | Strike-off or MVL (CGT-treated extraction at 10% with BADR) |
For most contractors the financial gap is meaningful but not life-changing, the qualitative differences are what tip the decision. A short-term contract for a risk-averse client makes umbrella the obvious choice even if outside would net more on the maths.
When to pick which (in practice)
Default to inside (umbrella) if…
- Your engager has determined inside IR35 (which they probably have, if they're medium/large).
- The engagement is short (under 6 months), the Ltd setup overhead doesn't pay back.
- You want to avoid all admin; PAYE payslips arrive automatically each week.
- You're early in your career and want statutory employment rights (sick pay, holiday pay, parental leave).
- Your IR35 risk appetite is low, even genuinely outside engagements have non-zero investigation risk.
Default to outside (Ltd) if…
- Your engager has determined outside IR35 (or you're working with a small client under Chapter 8, where you determine).
- The engagement is long (12+ months), admin overhead amortises.
- You're comfortable with self-assessment and statutory filings, or have a specialist contractor accountant doing it for £100/month.
- You'd benefit from the retained-earnings option (saving for a low-income year, capital extraction via MVL eventually).
- You expect to do meaningful pension contributions (£20k+/year) and want the Ltd's employer-pension efficiency.
Decision is murkier when…
- Your engagement is borderline outside-IR35 but the client is risk-averse. Get a specialist contract review (£200) before insisting on outside.
- You have an outside-IR35 engagement but have only one client. The lack of a portfolio is itself an IR35 risk factor; long-term you want multiple clients in parallel or rotation.
- You're moving from permanent to contracting for the first time. The Ltd setup is a real undertaking; umbrella for the first 6 months while you settle in is often the right call.
If your status changes mid-engagement
This happens more than people realise, a contract starts outside, the working relationship drifts toward employment patterns over months, and either you or HMRC reclassifies. What to do:
Engager re-determines you as inside (Chapter 10): you have 45 days to disagree via the Status Disagreement Process. If unsuccessful, you have to switch to PAYE (umbrella or direct from agency) for the remainder of the engagement. Income earned BEFORE the redetermination stays at outside-IR35 treatment, only forward income shifts.
You realise mid-engagement that the working practices have drifted to inside: the safe move is to declare the income as inside IR35 from the point of realisation onwards (operating deemed PAYE on your Ltd or switching to umbrella). For the prior outside period, you have a defensible position only if the working practices genuinely WERE outside back then — keep contemporaneous evidence (project plans, deliverable documents, substitution discussions).
Long engagements that stay at one client: even genuinely outside-IR35 work becomes harder to defend the longer it runs. After 18-24 months at one client, expect HMRC to scrutinise mutuality of obligation and integration factors more aggressively. Periodic role rotation, multiple clients in parallel, and explicit project-based engagement structures help.
Switching routes
Switching umbrella → Ltd, or Ltd → umbrella, between engagements is straightforward; mid-engagement is messier.
Umbrella → Ltd
- Incorporate the company (Companies House £50, online, same-day). Pick a name, register an address (your home works), name yourself as sole director and shareholder.
- Open a business bank account (Tide, Starling, Mettle are all fast, same-day approval typical).
- Register for corporation tax (HMRC, automatic within 3 months of incorporation).
- Register for VAT if expected turnover exceeds £90,000 (April 2024 threshold; 2026/27 may have updated this — check current threshold).
- Engage a contractor accountant (~£100/month) to handle CT return, annual accounts, payroll, self-assessment, VAT returns. Crunch / FreeAgent / Inniaccounts / SJD are common picks.
- Get IR35 insurance (Kingsbridge / Qdos) and PI insurance (Hiscox / Markel).
Realistic timeline from start to first invoice: 1-2 weeks. See our outside-IR35 Ltd calculator for the financial side, and the upcoming setting-up-Ltd guide for the full step-by-step.
Ltd → umbrella
Easier in the short term, more work in the long term. Pick an FCSA-accredited umbrella, sign the contract, and the agency switches the assignment to be paid via them instead. Your Ltd doesn't have to dissolve, many contractors keep the Ltd dormant in case future engagements are outside-IR35. You'll still need to file dormant-company accounts annually (£15 if doing it yourself, often £100/year via the accountant). Or you can dissolve the Ltd if you're sure you won't need it; cash extraction options range from final dividends (taxed normally) to MVL (CGT at 10% with BADR, requires a liquidator, ~£1,500-£3,000 fee).
Frequently asked questions
- Can I just choose to be outside IR35?
- No, IR35 status is a determination based on the substance of the engagement, not a choice. For medium/large private-sector and public-sector engagements (Chapter 10), the END CLIENT determines status, not you. For small private-sector engagements (Chapter 8 still applies), YOU determine status, but the determination has to be defensible against the three principal tests. If you'd be functionally an employee but call it outside-IR35 to take dividends, HMRC will catch up eventually.
- What's the actual £/year difference at typical day rates?
- At £500/day, 220 days, 2026/27 rates: outside-IR35 Ltd nets ~£69,129. Inside-IR35 umbrella nets ~£65,519. Difference is ~£3,610/year, about 5.5% of net pay. At £300/day the gap is smaller (~£2,000/year) because the dividend rate advantage is smaller. At £800/day the gap can SHRINK or even reverse because PA-taper kicks in above £100k of total income (the 60% trap) and additional-rate dividend tax is 39.35%, close to the marginal PAYE rate. Run your specific numbers in the calculator above.
- I had an outside-IR35 engagement determined as inside. Can I appeal?
- Under Chapter 10 (medium/large client) you have the Status Disagreement Process, the engager has 45 days to respond to your written disagreement with their reasoning. In practice, success rates are low because most engagers default to risk-averse 'inside' determinations and won't budge. If you genuinely believe the determination is wrong AND you have evidence (substitution exercised, multiple clients in parallel, working practices that don't match employment), escalate via a specialist (Qdos, Kingsbridge, IR35 Shield), they can sometimes negotiate where you can't. Tribunal appeals are theoretically possible but usually only happen for engagements worth £100k+ in disputed tax.
- Why did so many contractors move to umbrella in April 2021?
- April 2021 extended Chapter 10 (off-payroll determinations by the engager) to medium/large private-sector clients. Before then, contractors at FTSE companies determined their own status under Chapter 8, and many took the outside-IR35 position even when it was borderline. After April 2021, FTSE clients had to determine status themselves, and most of them blanket-redetermined existing engagements as inside (it was the safe option for their compliance officers). Contractors at those clients faced a binary: switch to umbrella or take a 5–7% net pay cut via deemed-payment Ltd. Most switched.
- Does inside IR35 affect my pension contributions?
- Yes, both routes can be tax-efficient, but the mechanics differ. Inside via umbrella: salary-sacrifice into pension is the most powerful single move available, capturing employee NI + employer NI savings (because the assignment-rate is fixed, the saved ER NI flows back to you as more comp). Effective marginal saving on a sacrificed £1 is ~50-60% for higher-rate earners. Outside via Ltd: the company pays employer pension contributions directly, saves corporation tax (19-25%) AND bypasses personal income tax / NI / dividend tax entirely. For typical contractors the Ltd route is usually slightly more tax-efficient than umbrella SS, but both are far better than personal pension contributions from net pay.
- If I'm inside IR35, can I claim travel and subsistence?
- Mostly no, post-2016. The Finance Act 2016 introduced the Supervision, Direction, and Control (SDC) test, if your client controls how you do your work (which is the case for most inside-IR35 engagements), you can't claim travel and subsistence as tax-free expenses. The exception: chargeable expenses approved in advance by the client and charged back through the agency. These flow through the umbrella as a billable cost, not an employee expense, and don't reduce your tax bill.
- Will inside vs outside affect my mortgage application?
- Mostly the same outcome via different paths. Outside-IR35 Ltd: lenders use 2 years of salary + dividends drawn (Halifax / Clydesdale / Saffron specialist lenders use net profit before extraction, which gives a higher figure). Inside-IR35 umbrella: lenders treat your umbrella payslips as standard PAYE income, so high-street lenders will use 3-6 months of payslips and apply a normal income multiple. For a contractor with stable engagement history, the umbrella route is sometimes EASIER because PAYE payslips look more conventional to underwriters. See the self-employed mortgage calculator for the full picture.
- What if my contract is genuinely outside but the engager determines inside?
- You have three options. (1) Accept it and work through umbrella, many contractors do this rather than walk away from the engagement. (2) Use the Status Disagreement Process to challenge the determination, low success rate but free. (3) Walk away and find a different engagement with a more risk-tolerant client. Some contractors specialise in working ONLY with clients (often smaller / Chapter-8-exempt) who'll take outside-IR35 determinations. The real-world practical answer for most contractors today: if you want outside-IR35 work, you have to actively seek out clients who'll engage on those terms, most BigCo defaults are inside.