How to compare two job offers on what you’ll actually keep

Why does headline salary give you the wrong answer?

Two offers at the same salary can deliver meaningfully different take-home. Pension sacrifice percentages change adjusted income and therefore the tax band each pound sits in. Student loan repayments can apply to employment income processed through payroll — including salary, bonuses and RSU vests — so a higher income can mean higher repayments. Sign-on bonuses can inflate early-year compensation, then reduce or disappear later.

Add RSUs to the mix and the comparison becomes multi-year. A lower salary with an equity grant can deliver more total net compensation over the vesting period — but only if you look at the net figures after deductions, not the gross grant value. The two are not the same thing, and the gap between them can be significant.

What do you actually need to compare?

A useful comparison has five components:

• Net monthly take-home from salary. Gross salary minus pension sacrifice, income tax, employee National Insurance, and student loan. This is the number that arrives in your account each month — not the gross.
• Net sign-on bonus after deductions. A sign-on bonus is employment income, taxed at your marginal rate. A £10,000 sign-on does not deliver £10,000. How much it delivers depends on what income is already stacked underneath it in that tax year.
• Net RSU value, year by year. Each vest is employment income on top of salary. The deduction rate depends on where the salary sits in the tax bands — and whether combined income crosses the Personal Allowance taper at £100,000.
• How compensation changes from Year 1 to Year 2, 3, 4. Year 1 is often the outlier — a sign-on bonus inflates it and then vanishes. The vesting schedule determines how much equity income arrives in each subsequent year.
• Threshold exposure. Does either package — when salary, bonus and RSU vests are combined — push adjusted income across £100,000? If so, the effective marginal rate on that slice can reach 60% or higher before student loan repayments are added. This changes the net value of the package materially.

What does this look like with real numbers?

Two companies, both asking you to choose. Company A leads on salary. Company B leads on equity and pension contribution. Here are the packages:

All figures below use the same calculation approach as the PayFluency calculator and have been checked against the current calculator engine. This example uses a simplified full-tax-year model. Real outcomes depend on start date, payment month, tax code, previous income in the year and payroll timing.

Step 1 — net monthly take-home from salary

After pension sacrifice, the income each employer’s PAYE system sees is different: Company A £80,750 (£85,000 minus 5%), Company B £69,000 (£75,000 minus 8%). The deductions stack up like this:

Company A delivers £479.79 more take-home per month from salary — about £5,758 per year. The headline salary gap is £10,000; the net take-home gap is roughly half that.

Step 2 — net sign-on bonus after deductions

Sign-on bonuses are employment income, taxed at the marginal rate on top of salary for that tax year. Neither company’s combined Year 1 income crosses £100,000, so no Personal Allowance taper applies to either.

Both bonuses fall at a combined 51% marginal rate — 40% income tax, 2% employee National Insurance above the upper earnings limit, 9% Plan 2 student loan — because both bases sit in the higher-rate band and above the relevant thresholds.

Step 3 — net RSU value (Company B only)

Company B’s grant is 200 shares at £200 = £40,000 total. At 25% per year, Year 1 vests 50 shares worth £10,000 gross. Because a sign-on bonus is also active in Year 1, the RSU deductions are calculated on the stacked base — salary-adjusted income plus the bonus gross, £74,000 — to reflect the correct marginal position.

In Years 2, 3 and 4 — no bonus active, so the RSU base is salary-adjusted income only: £69,000. The marginal rate on the vest (combined £79,000) is unchanged — all income falls in the higher-rate band, above the NI upper limit and above the Plan 2 threshold. Net RSU remains £4,900 per year.

How does the four-year picture compare?

Combining salary take-home, sign-on bonus net, and RSU net for each year:

Company A delivers more take-home over four years — but by £5,882, not the £40,000 the headline salary difference across four years might suggest. The deduction structure compresses the advantage considerably.

What the take-home table doesn’t show

Four things the comparison above does not capture:

• Pension contributions are real value, even when invisible in take-home. In this example, the amount sacrificed into pension is £4,250 per year for Company A and £6,000 per year for Company B — £17,000 and £24,000 respectively over four years. Company B contributes £1,750 more per year. When pension is added alongside take-home, the four-year totals become £232,980 (Company A) and £234,098 (Company B). Whether a pound in pension is equivalent to a pound in take-home depends on individual circumstances — pension money is locked until retirement age and carries investment risk that cash does not.
• RSU values assume a fixed share price. The worked example uses £200 per share throughout. If the share price at each vest differs from the grant price, the gross vest value and all downstream deductions change accordingly. Equity compensation carries market risk that cash compensation does not. A lower share price at vest reduces the net outcome; a higher one increases it.
• Sign-on bonuses can come with clawback clauses. Some clawback clauses require repayment of the gross bonus, not just the net amount received. Terms vary — some apply for 12 months, others for 24 months or longer. The sign-on terms are worth checking before treating it as unconditional income.
• Tax year timing matters in the start year. This guide models full-year income at each salary. If you start mid-year, salary income is partial — but a sign-on bonus and first RSU vest may both land in that same tax year, alongside income from your previous employer. Real Year 1 deductions depend on your start date and any in-year income from elsewhere.

The informed decision

A clear offer comparison models net take-home across the full compensation period — not just Year 1, and not just salary. Understanding the deduction profile of each package, including how RSUs, bonuses and pension interact with tax thresholds, is what turns a headline comparison into a useful one.

In this example, the take-home picture is more compressed than the salary gap implies, the equity contribution is meaningful but carries risk, and the pension comparison tells a different story from take-home alone. None of those facts are visible from the headline figures.