PAYE vs Self Assessment Student Loan Calculator
See what payroll collects during the year, what Self Assessment charges on the same income, and the balancing payment that settles the difference.
Read our guide on PAYE vs Self Assessment student loans for the reasoning behind the numbers below.
Important Note
PAYE gives every employment its own threshold. Self Assessment gives you one threshold for all of your income, so it can only ever ask for the same amount or more.
England 2012-2023; Wales 2012 onwards
Plan Details, 2026-27
Outcome: a balancing payment is due
Self Assessment collects more
£7.35 still to pay on 31 January 2028
Payroll collected £48 of a £55.35 liability, because the monthly threshold is floored and each period's deduction is rounded down to a whole pound.
PAYE against Self Assessment, 2026-27
PAYE collects during the year
£48
12 pay periods, 1 employment
Self Assessment charges
£55.35
On £30,000 of aggregated income, 2026-27
Due 31 January 2028
£7.35
Payroll covered 87% of the liability
How this is worked out
(£2,500.00 − £2,448) × 9% × 12 = £48
PAYE on employment 1: one month's pay against the monthly Plan 2 threshold, each period rounded down to a whole pound the way HMRC's payroll rules require, then multiplied by 12 periods.
How this is worked out
(£30,000 − £29,385) × 9% = £55.35
Self Assessment: every source added together and tested once against the 2026-27 annual Plan 2 threshold.
How this is worked out
£55.35 − £48 = £7.35
The balancing payment: the annual liability less the student loan your employers already deducted. Due 31 January 2028.
Rates, assumptions and sources
Every figure below is the 2026-27 published figure, read from this site's single source of truth at page-render time[source]. The 6% Plan 2 and Postgraduate interest cap covers the 2026/27 year only and is not assumed to continue[source].
| Plan | Threshold | Rate | Interest | Written off | Threshold freeze |
|---|---|---|---|---|---|
| Plan 2 | £29,385[source] | 9% | 4.1% to 7.1% by income, capped at 6% for 2026-27[source] | 30 years[source] | Frozen at £29,385 until April 2030 |
Write-off is counted from the April after the course ends, not from the course-end date itself, and the Plan 2 interest bands (£29,385 lower, £52,885 upper) are frozen alongside the Plan 2 repayment threshold.
This calculator also assumes
- Pay spread
- Each employment paid evenly across 12 periods
- Monthly threshold used
- £2,448
- Per-period rounding
- Each deduction rounded down to a whole pound (HMRC CWG2)
- Balancing payment due
- 31 January 2028
- Payments on account
- None for student loans
Growth, inflation and long-run interest figures are assumptions, not published rates. Change them and the projection changes.
Key Insights
The gap only runs one way. Every employment gets its own threshold under PAYE, so the sum of the per-job deductions falls short of the liability Self Assessment works out on the total. The difference is a shortfall to settle, not an overpayment to reclaim. (With one job paid evenly all year the two land within pennies of each other, because HMRC floors the per-period threshold and rounds each deduction down to a whole pound.)
Multiple employments: two jobs paying £14,693 each deduct nothing through payroll all year, then produce a full year's liability on the return.
Payment timing: PAYE spreads repayments across the year; the Self Assessment balancing payment lands in one go on 31 January 2028. Student loan repayments are not included in payments on account. They are collected once a year, with the balancing payment on 31 January. Your income tax and Class 4 NIC payments on account are worked out without them.
Uneven pay is the exception: a bonus or a spike in one month of a single job can make payroll deduct more than the year's rules require. Self Assessment does not refund that; a reclaim goes to the Student Loans Company. See the bonus month PAYE calculator.
How PAYE vs Self Assessment Affects Student Loan Repayments
PAYE System
- • Repayments deducted automatically from salary
- • Each employment treated separately
- • Threshold applied to each job individually
- • Payments spread throughout the year
- • Under-collects when you have more than one job
Self Assessment
- • Annual calculation based on total income
- • All income sources aggregated
- • Single threshold applied to total income
- • Balancing payment on 31 January
- • Collects whatever PAYE did not
When Differences Occur
The gap between what payroll collects and what the return charges is widest when you have:
- • Multiple part-time employments, each under the threshold
- • A combination of employment and self-employment income
- • Unearned income over £2,000, which counts in full once it crosses that line
- • Income from different sources (employment, freelancing, rental income)
If you have several income sources that individually fall below the threshold but together exceed it, Self Assessment charges the full annual amount and credits the little or nothing PAYE collected. You pay more through the return than payroll took, never less — the difference is the balancing payment, and it is due in one payment on 31 January 2028.
Need Professional Advice?
If your Self Assessment student loan figure is larger than you expected, a tax adviser or HMRC can confirm which income sources HMRC counted.
Related student loan calculators
The PAYE vs Self Assessment calculator answers one specific question. For the full picture, start with our UK student loan calculator on the homepage, work out what leaves your payslip each month with the monthly repayment calculator, or check what you can borrow with the student finance calculator. Every tool on the site is listed in the UK student loan calculator directory.
- self-employed student loan calculator: what you owe through Self Assessment rather than PAYE
- Self Assessment balancing payment calculator: the extra student loan HMRC collects with your tax return
- SLC voluntary payment vs Self Assessment top-up: which route to use when you want to pay extra