How we calculate

Every calculator on Family Sums follows the same approach.

• One set of figures per year. All rates and thresholds for 2026/27 sit in a single dated data file. Calculators read from that file, so a rate changes in one place and every page updates together.
• Official sources only. Each figure comes from GOV.UK, a devolved government, a student finance body or UCAS. Where an official body publishes a figure only through partners, such as the 2026/27 Student Finance England income tables, we use a university’s copy of the official table and say so.
• Tested sums. Each calculation has automated tests, including the worked examples published by official bodies where they exist. A change that breaks a test can’t go live.
• Rounding like the official source. For example, Statutory Maternity Pay is rounded up to the next penny, and student loan deductions are rounded down to the pound each pay day.
• Plain limits. Every page has a “what this calculator doesn’t cover” section, so you know when to check with the official service instead.

When we update

• Each April for maternity pay and student loan thresholds, which change with the tax year.
• Each spring and summer for student finance and EMA rates for the next academic year.
• Each term for funded childcare rules, which have changed often since 2024.
• Whenever a government announces a change, such as in a Budget.

Every page shows the date it was last checked. We only change that date when someone has actually checked the figures again.

Assumptions by calculator

• Nursery cost and funded hours calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• Statutory Maternity Pay calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• School year calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• School attendance percentage calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• School Essentials Grant checker (Wales): see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• UCAS points calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• Degree classification calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• Maintenance loan calculator (England): see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• Student loan repayment calculator: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.
• EMA Wales eligibility checker: see “How it’s worked out” and “What this calculator doesn’t cover” on the page.

Your data

Calculations run in your browser. What you type isn’t sent to us or stored on a server. Your inputs appear in the page address so you can share or reopen a result, so take care when sharing that link.