Example result based on the prefilled values.
Comparison
Overpayment route increases total cash paid before write-off in this model
Mandatory-Only Cash Paid
£62,167.03
Mandatory-Only End Status
Balance remains at modelled write-off
Mandatory-Only Balance at Write-off
£22,444.92
Overpayment Route Cash Paid
£67,167.03
Overpayment Route End Status
Balance remains at modelled write-off
Overpayment Route Balance at Write-off
£9,820.11
Cash Paid Saving From Overpayment
£-5,000.00
Interest Accrued Reduction
£7,624.81
Continue your plan
Useful next calculations
Rates & sources2026/27 starting thresholds
Annual scenario model starting with confirmed 2026/27 plan thresholds. Interest, salary growth, future threshold growth and years to write-off are entered by the user and are not forecasts.
Source: HMRC — 2026/27 student-loan thresholds — source checked for 2026/27 starting thresholds.
When to use this calculator
- When you need a fast estimate before making a bigger decision.
- When you want to compare a few scenarios using the same assumptions.
- When you need a clearer starting point before using a detailed quote or formal document.
- When you want to sanity-check a figure you have seen elsewhere before you rely on it.
- When you are preparing for a conversation with an adviser, supplier, or lender and want to arrive with realistic numbers.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Student loan plan
Plan 1
Current loan balance (£)
£200,000
Current annual repayment income (£)
£35,000
Assumed annual salary growth (%)
£35,000
After entering these figures, review comparison, mandatory-only cash paid and mandatory-only end status together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Comparison
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Mandatory-Only Cash Paid
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Mandatory-Only End Status
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Mandatory-Only Balance at Write-off
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Overpayment Route Cash Paid
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Overpayment Route End Status
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Overpayment Route Balance at Write-off
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Cash Paid Saving From Overpayment
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Interest Accrued Reduction
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This decision calculator compares two annual projections: continuing with income-contingent mandatory repayments, and adding the one-off or annual voluntary payments entered. Each route uses the selected plan's confirmed 2026/27 threshold initially, then applies the user-entered salary, threshold and interest assumptions.
The result separates cash actually paid from the balance remaining at the modelled write-off. This distinction matters because interest accrued on a balance that is ultimately written off is not the same as cash cost to the borrower. A voluntary payment can reduce interest yet still increase lifetime cash paid.
The model is annual and cannot predict income, government policy, future thresholds or loan rates. It does not model postgraduate loans, multiple concurrent plans, overseas fixed repayments, refunds or payroll timing. Confirm the balance and write-off terms with the Student Loans Company before making an irreversible voluntary payment.
Common mistakes
- !Using optimistic assumptions without testing a more cautious scenario as well.
- !Comparing outputs from different tools without checking that the inputs match.
- !Treating the result as a final quote instead of a planning estimate.
- !Rounding inputs too aggressively, which can produce an output that is noticeably different from your actual situation.
- !Stopping at a single run of the tool rather than adjusting the key variable up and down to understand the range of plausible outcomes.
What to do next
- Try at least one more scenario so you can compare a realistic range instead of a single estimate.
- Use the related calculators below to cross-check the decision from another angle.
- Open one of the linked guides if you need more context before you act on the result.
- Write down the key outputs from your best two or three scenarios so you have something concrete to compare when you make the final decision.
- If the result surprises you, change one input at a time to isolate which variable is driving the outcome before drawing conclusions.
Frequently asked
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