RSU Tax Calculator: UK & Ireland

RSUs are taxed as ordinary income on the full market value at vest, there's no strike price to offset it. In this calculator's UK example, 500 shares vesting at £40 creates a £20,000 vest value, taxed at roughly £8,400 in Income Tax and Class 1 National Insurance combined, on top of £70,000 other income. In Ireland, the same numbers create a €20,000 vest value taxed at roughly €10,438 across PAYE, USC, and PRSI together.

Because vest value stacks on top of your existing salary and gets taxed at your marginal rate, and for higher earners in both the UK and Ireland that marginal rate is high once Income Tax, NI/PRSI, and USC (Ireland) are combined. A UK additional-rate taxpayer sees 45% Income Tax + 2% NI on the vest value; an Ireland higher-rate taxpayer sees 40% Income Tax + up to 8% USC + roughly 4.2% PRSI, which is exactly why the commonly quoted 52% figure comes up so often for Irish RSU vests. This calculator shows your actual marginal rate rather than a generic headline figure.

For the vest leg, yes, in both countries. UK and Irish employers withhold RSU vest tax through payroll, usually via a sell-to-cover mechanism that automatically sells enough vesting shares to cover the tax bill, so you receive the net shares (or net cash) directly. What your employer does NOT handle is the sale leg: any further gain between the vest-date value and your eventual sale price is a separate Capital Gains Tax event you're responsible for reporting and paying yourself.

Not for the vest-tax mechanism. If you're UK or Ireland tax resident when the shares vest, your employer (or its local payroll/broker arrangement) withholds Income Tax + NI (UK) or PAYE + USC + PRSI (Ireland) exactly as if the shares were from a domestic company. In Ireland specifically, this is a common point of confusion: RTSO1 self-assessment, the form some people associate with share-scheme tax, applies only to share options, never to RSUs, regardless of whether the grant comes from a domestic or foreign parent.

Your cost basis for CGT purposes is the vest-date value, not zero, since you already paid income tax on that amount. Only further appreciation from vest to sale is a capital gain. In the UK, that gain is taxed at 18% or 24% depending on how much of it falls within your remaining basic-rate band, after a £3,000 annual exempt amount, a rate that changed materially after the October 2024 Budget aligned share and property CGT rates. In Ireland, it's a flat 33% after a €1,270 annual exemption, regardless of your income level.

The vest tax, yes, always, it's due the moment shares vest regardless of whether you sell any of them, which is exactly why sell-to-cover exists (to raise the cash without you needing other funds). The CGT leg only applies once you actually sell, so if you hold vested shares without selling, you owe vest tax now and nothing further until a future sale, at which point CGT applies to whatever gain (or loss) has accrued since vest.

No, this calculator models a single vest-and-sale event. Real RSU grants typically vest in tranches over 3-4 years, each tranche at a different share price on its own vest date, and each needs calculating separately since the vest-date value (your cost basis for CGT) differs per tranche. Run this calculator once per tranche if you're working out a multi-year grant.