General Calculators
Percentage Calculator
Quickly calculate percentages, percent of a number, and percent change.
Discount Calculator
Find the sale price after a percent discount and how much you save.
Loan Payment Calculator
Estimate your monthly loan payment from amount, rate and term in years.
Unit Price Calculator
Compare price per unit between two products to find the better deal.
About our free general calculators
Everyday calculators for percentages, discounts, loan payments and unit pricing. Whether you are a small business owner, a tradesperson on the job site, a restaurant manager pricing a menu, or a homeowner planning a project, our general calculators are designed to give you a clear answer fast — with no signup, no paywall, and no data leaving your device.
Every tool in the General Calculators category was built around a real-world question we kept seeing online: "How much paint do I need?", "What should my menu price be?", "How do I make a clean invoice?". Instead of forcing you through a long form or a marketing funnel, we give you the calculator or generator at the top of the page and the helpful background information below.
Designed for the US market
Our general calculators use US units (feet, square feet, inches, gallons, cubic yards, ounces) and US dollars by default, with formulas tuned for typical American homes, contractors, small businesses and restaurants. If you are in Ohio, the Midwest, or anywhere in the United States, the defaults will feel familiar.
Browser-based and private
Every calculation happens locally in your browser using JavaScript. Image and file tools use the HTML canvas API, so your photos and documents never leave your device. That makes the tools fast, private and usable even on slow Wi-Fi.
Always free
All 4 general calculators on this page will remain free forever. The site is supported by non-intrusive advertising, not by selling your data or hiding the tool behind a paywall.
Tips for using these tools
- Enter realistic numbers — the more accurate your inputs, the more accurate the estimate.
- Always add a buffer for waste or overruns when ordering materials, food or supplies.
- Use the printable outputs (where available) to share results with a client or coworker.
- Bookmark this page so you can come back next time you need the same calculator.
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Frequently Asked Questions
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