— For UK earners over £100k
Your effective marginal rate isn't 40%. It's 62%.
The cliff edge between £100k and £125,140. Personal allowance taper + 40% income tax + 2% NI. Most HENRYs don't realise the maths until a bonus disappears. 30-second sanity check below.
Every payslip you wait makes the cliff bigger to climb back. Run the numbers.
The actual numbers
Work out what your next pound is actually worth.
£5,500 into your pension per year (via salary sacrifice)
Tax + NI this year
£33,783
31% of gross
You take home
£70,717
£5,893/month
Personal allowance
£10,320
tapered from £12,570
And on the next pound you earn
You're inside the personal allowance taper. For every extra £1 you earn between £100k and £125,140, HMRC takes 60p — plus 2p in NI.
The salary sacrifice fix
Salary-sacrifice an extra £4,501 into your pension to drop your adjusted income to £99,999 — and recover roughly £2,340 a year.
Tax + NI saved
£2,340/yr
Extra in your pension
+£4,501/yr
Take-home change
−£2,161/yr
By retirement
£299,041
What the extra pension contribution compounds to over 30 years at 5% growth — working for you instead of disappearing to HMRC.
Illustrative — assumes 5% annual growth, not guaranteed. Investments can fall as well as rise.
Take-home dips slightly because more goes into your pension. But the money grew tax-free, the NI saving is real, and (if you have kids) you keep the funded childcare. Net: for most people in this band, the maths works out ahead — Theo runs your specific version.
The next step
Want Theo to run this optimisation on your numbers — every payday?
The full optimisation, running on your actual numbers, every payday. Adjusts for bonuses, RSU vests, and pay rises. Reminds you before 5 April to top up. No spreadsheets. No tax accountant.
Estimates use 2026/27 UK tax bands (England, Wales, NI). Scotland uses different bands. Assumes employee Class 1 NI and salary-sacrifice pension. Real outcomes depend on your specific situation — Theo runs the full calculation on your actual numbers, including annual allowance and tapered annual allowance for high earners.
The cliff, visualised
Your real marginal rate across the bands.
Each band is what HMRC takes on the next pound you earn at that salary. The cliff between £100,000 and £125,140 is where the personal allowance taper kicks in — and where your effective rate is briefly higher than the additional-rate band above it.
Every extra pound in the cliff band
Salary-sacrifice into your pension until your adjusted income drops below £100k. The cliff unlocks. The personal allowance comes back. The pound goes into your pension instead of HMRC. The fix exists. Almost nobody is told.
The boring is sorted. The fun is yours.
A scenario you’ll recognise
Same job. Same paycheque. Two outcomes.
Tom, 33. Tech AE. £105k base + £15k OTE. One kid in nursery. A Q2 commission cheque pushes his adjusted income to £120k — straight into the cliff. Salary-sacrificing the excess into his pension changes the picture entirely.
Tom’s net result
£14,300 back this year. £20,000 working in his pension.
Tom isn’t bad with money. He just isn’t told the maths.
Composite scenario, drawn from common HENRY situations on r/HENRYUK and our user conversations. Run your own numbers above.
What Theo does
Not a one-off calculator. Theo runs every decision, every payday.
Reads.
Your full financial life — current accounts, savings, ISAs, pensions, mortgage, debts — through regulated Open Banking. Not a slice. The whole picture, kept current automatically.
Thinks.
About every money decision you face. ISA allocation. Pension consolidation. Mortgage vs invest. Tax-year-end top-ups. The £100k cliff today, the spring bonus next quarter, the old workplace pensions you’ve forgotten about — what to do, on your numbers, in plain English.
Watches.
Every payslip, bonus, threshold, life event, regulatory change. Quietly, every payday. Nudges you only when there’s an actual reason. The optimisation a £200/hour adviser would do — running in the background.
“Yes, earning £100k+ is a good problem to have — I know that. But the cliff is one of the worst-designed bits of UK tax and most HENRYs lose four-figure sums to it every year just because nobody explains the maths. I built Theo because I was sat on the same problem myself.”
— Ciaran Hughes, Founder
Theo is financial guidance — not regulated advice. We hold ourselves to the standard of the FCA's Consumer Duty even though, as a guidance service, we're not required to. Encrypted at rest and in transit. Never sold.
— A closing argument.
Stop sending HMRC 62p of every extra pound.
Join the waitlist. Theo runs the full optimisation on your actual numbers at launch — every payslip, every bonus, every 5 April.
Summer 2026 · Free · No card