Use these calculators to answer everyday percentage and campaign planning questions in seconds.
These calculators handle the number questions that slow you down day to day: how big a tip to leave, how to split a shared bill fairly, what a discount really comes to, and how much a figure changed over time. Each one focuses on a single task, so you get an answer in seconds without building a spreadsheet.
All of them are free, need no sign-up, and run in your browser, so your numbers stay on your device.
Percentage Calculator
Find percent of a number, compare values, and calculate percent change.
FairTab Group Expense Splitter
Split group expenses with no signup and get a simple settle-up plan.
UTMatic
Generate campaign URLs with structured UTM parameters.
How to choose
Reach for the percentage calculator for tips, discounts, and change over time. Use the expense splitter when several people share a bill and you want a fair settle-up. Pick UTMatic when you need a campaign link that reports cleanly in analytics.
Related guides
- How to split a group bill fairlyA practical method for dividing shared costs so the totals always add up.
Frequently Asked Questions
- Are these calculators free?
- Yes, all calculator tools on STSApps are free.
- Do I need an account?
- No sign-up is required for calculator usage.
- Do they work on my phone?
- Yes, every calculator works on mobile and desktop browsers.
- Are my numbers saved?
- No. Calculations run in your browser and are not stored.
- Can I use decimals?
- Yes, the calculators accept whole numbers and decimals.