Calculator widgets for your website
Free to put on any site, commercial ones included. Choose the colours and options, copy one snippet, and paste it wherever the calculator should appear. No account, no fee, no tracking, and nothing to maintain afterwards.
Loan calculator
Monthly payment, total interest and the share of every payment that is interest, for a car, a personal loan or anything amortizing.
For dealers, credit unions and personal finance writing, where readers arrive ready to borrow.
Get the code โPercentage calculator
The four percentage questions people actually ask, each answered in a sentence as well as a number.
Enormous search demand, and it belongs on almost any page.
Get the code โBMI calculator
Body mass index with the WHO category, a marker on the scale, and the healthy weight range for that height.
For gyms, clinics and nutrition sites.
Get the code โCompound interest calculator
What a balance grows to, with monthly deposits and any compounding frequency, split into what you put in and what the interest added.
For investing and personal finance writers, where the point is showing the effect over time.
Get the code โUnit converter
Length, weight, volume, temperature, area and speed, with the defining factors rather than rounded ones.
For recipe sites, trades and any page with an international audience.
Get the code โBasic calculator
The four operators, percent, square root and memory, with real order of operations and keyboard input.
For any page where a reader needs to work out a number without leaving.
Get the code โMortgage calculator
Monthly payment, total interest and a principal against interest split, with optional tax, insurance, PMI and HOA rows.
For property listings, brokers and personal finance writing.
Get the code โScientific calculator
Trigonometry, logarithms, powers, roots, factorial and memory, with real operator precedence and keyboard input.
For education, engineering and science pages where readers need to work something out on the spot.
Get the code โConcrete calculator
Volume and bag counts for slabs, columns and rings, with a waste allowance and a drawing of the shape being measured.
For builders, hardware retailers and home improvement writing.
Get the code โHow these work
Each widget is a single script and a single div. Paste both into your page and the calculator appears where the div sits. Everything runs in your visitor's browser, so nothing is sent to us, nothing is stored, and no cookie banner is needed on account of the widget.
They are built to survive contact with a real website. Each one renders inside a shadow root with its own stylesheet, which means your theme cannot break the calculator and the calculator cannot leak styles into your page. We test that against a deliberately hostile stylesheet, the kind that sets width and font on every input with !important.
You can put more than one on a page, each with its own colours and settings, and they will not interfere with each other. Two versions of the code are offered: a hosted script that updates automatically when we improve something, and a standalone block that contains everything and stays exactly as you copied it.
The one thing we ask is that the small credit link stays. That link is the only reason these are free.
Want a widget for a calculator that does not have one yet? Tell us which one on the contact page and it will go on the list.