The number of times I have opened a new tab, typed a calculation into the URL bar, waited for search results, and then had to find the calculator widget among ads and links — this is an embarrassing amount of friction for a simple math problem.
The alternative was to build a calculator that IS the new tab.
What Quick Calculator and Unit Converter does
Replaces your Firefox new tab with a full-featured calculator. Arithmetic, percentages, scientific notation. Also: currency conversion, unit conversion for length, weight, temperature, and volume.
You open a new tab, you are immediately at a calculator. No URL bar math, no Google calculator widget, no opening a separate app.
Why unit conversion in the same interface
Calculations and conversions often happen together. I am looking at a recipe and need to convert cups to liters while also calculating scaling factors. Having both in one place removes the round-trip.
The currency data updates automatically from public rates. The other conversions are offline — they do not need network access.
The design decision: replace the new tab
This is an aggressive choice. If you rely on new tabs for search, this changes your workflow. The extension keeps the address bar functional — you can still search from there. But the new tab canvas is a calculator.
Whether this is the right trade-off depends on your workflow. If you do frequent calculations throughout the day, the trade is worth it. If your new tab is primarily for navigation, consider whether the occasional calculation justifies the cost.
Install it
Quick Calculator and Unit Converter — Firefox Add-ons
Free. No account. Works in Firefox.
This is one of 11 Firefox extensions I built — all free, no-account, no-server. See the full series for the others.
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