Free calculators that just work
Quick, accurate answers for everyday money and maths. Pick a tool and the results update as you type.
- Free
- No sign-up
- Instant results
- Works on any device
All tools
- VAT Calculator Add or remove UK VAT at 20%, 5% or 0% and see net, VAT and gross instantly. £100 + 20% VAT = £120 Open calculator
- Percentage Calculator Work out X% of a number, what percentage one number is of another, or a percentage increase or decrease. 20% of 150 = 30 Open calculator
- Salary Calculator Convert pay between annual, monthly, weekly, daily and hourly – down to the second. £32,000 a year = £16.41 an hour Open calculator
- Days Since / Until Calculator Count the days until a date or since a date, with Christmas, Easter, Black Friday and more. Days until Christmas Open calculator
- Measurement Converter Convert length, weight, volume, temperature and area, plus grams to cups for baking. 1 inch = 2.54 cm Open calculator
Why OneClickTools?
Instant
No Calculate button and no waiting. Results appear as you type, with one-click copy buttons for every figure.
No sign-up
No accounts and nothing to install. Your numbers are worked out in your browser, so results appear straight away.
Clear
Every tool explains how it works, with worked examples and plain-English answers to common questions.
Frequently asked questions
Are the tools really free?
Yes. Every calculator is free to use, with nothing to sign up for and no limits on how often you use it.
Do you store the numbers I enter?
No. Calculations happen in your browser and there are no accounts or databases, so the numbers you enter aren’t saved.
How accurate are the results?
Each calculator shows how its results are worked out and rounds sensibly, such as to the nearest penny for money. They’re for guidance, though: for tax or financial decisions, check GOV.UK or speak to an accountant.