Everyday calculators for everyday needs: work out your exact age in years, months and days; calculate a percentage of any number; split a restaurant bill including service charge; convert between metric and imperial units; compute the difference between two dates in working days; and adjust historical prices for UK inflation using ONS CPI data.
Last verified: April 2025 against HMRC, Ofgem and gov.uk sources for the 2025/26 tax year.
Every tool below is free, requires no sign-up and uses 2025/26 UK rates.
8 general calculators covering age, percentage, tip, unit converter.
Not sure which tool to start with? Here's a quick guide to the most-used calculators in this category — pick the one that matches your situation.
Track your assets minus liabilities to calculate your UK household net worth.
Plan your monthly budget by entering income and expenses across all categories to see your surplus or shortfall.
Find out what a sum of money from the past is worth in today's money, or how much prices have risen over time using UK CPI data.
| Calculator | Best for | Time to use |
|---|---|---|
| Net Worth Calculator | Track your assets minus liabilities to calculate your UK household net worth. | Under 1 min |
| Budget Planner | Plan your monthly budget by entering income and expenses across all categories to see your surplus or shortfall. | Under 1 min |
| Inflation Calculator | Find out what a sum of money from the past is worth in today's money, or how much prices have risen over time using UK CPI data. | Under 1 min |
| Age Calculator | Calculate your exact age in years, months, weeks and days. | Under 1 min |
| Percentage Calculator | Calculate percentages, percentage change, percentage difference and more. | Under 1 min |
| Tip Calculator | Calculate a tip and split the bill between any number of people. | Under 1 min |
Pick the calculator that matches your need
Net Worth for big-picture wealth, Budget Planner for monthly cashflow, Inflation for historical purchasing power, Date/Age for tax-year-window questions.
Use UK measurements
UK pint = 568ml, UK gallon = 4.546L. US measurements differ (US pint 473ml, gallon 3.785L). Specify your locale.
CPI vs RPI matter
For most UK purposes use CPI (official measure since 2010). RPI runs ~0.8pp higher and persists for rail fares, pre-2023 student loans, and legacy contracts.
Mind percentage maths
A 50% rise followed by a 50% fall does NOT return you to start — leaves you 25% down. Always verify percentage operations against absolute values.
Date math for tax deadlines
Self Assessment 31 Jan + 31 Jul payments. CGT property disposal 60 days. SDLT 3-year additional-property reclaim. Use Date Difference for precise day counts.
Disclaimer: All calculators on this page provide estimates for guidance only and do not constitute financial, tax or legal advice. Tax rules can change at any time — always consult a qualified professional or check gov.uk before making financial decisions.