About Daily Calculator

Our mission

Most people reach for a calculator site a few times a week: to work out a tip, convert a temperature, check a mortgage payment, calculate a percentage change or estimate how much paint a room needs. These small tasks should not require an account, a cookie banner or a slow page bloated with ads and popups.

Daily Calculator was created to answer a simple question: what would a calculator website look like if it prioritised speed, clarity and privacy above everything else? The result is a static, browser-only site where every tool loads quickly on a phone, shows the formula it uses, and runs the calculation locally rather than sending your numbers to a server.

In one sentence: a free, fast, privacy-first library of calculators where every tool explains its own maths.

What we offer

Daily Calculator currently publishes over 230 calculators and converters across eight categories. Every tool has its own page and its own URL, so it can be bookmarked or linked directly:

Math and statistics — arithmetic, percentages, fractions, averages, probability, standard deviation, z-scores and number theory.
Geometry and construction — triangle solvers, circle and polygon tools, area and volume, plus concrete, tile, paint and flooring estimators.
Finance — mortgage, loan, interest, savings, retirement, investment, salary, tax and everyday money calculators.
Health and fitness — BMI, BMR, TDEE, calorie, macronutrient, body-fat, heart-rate and pregnancy estimators.
Date and time — age, date differences, business days, week numbers, timesheets, time zones and Unix timestamps.
Unit converters — length, weight, temperature, volume, area, speed, pressure, energy, data and cooking measures.
Engineering — Ohm's law, voltage drop, BTU, horsepower, gear ratio, molarity and thermodynamics helpers.
Computing — IP subnetting, base conversion, Base64, URL encoding, password generation, GPA and grades.

Alongside the calculators, we publish a growing library of calculation guides that explain the formulas and how to interpret results in plain English.

How the calculators work

Every calculator on this site is implemented as a small, well-tested JavaScript module. When you open a page and enter values:

Your input is validated in the browser — empty fields, malformed numbers and out-of-range values are caught before any maths is run.
The calculation is performed locally using the formula documented on the page.
The result is displayed in a result panel, with optional detailed breakdown, table or amortization schedule.
No input values leave your device. There is no server-side calculation step.

The formula used by each calculator is explained on the page itself, along with a worked example and any important assumptions. This makes it possible to verify a result independently, or to reuse the same formula in a spreadsheet.

Privacy and data

Daily Calculator does not require an account and does not collect personal information. Specifically:

Calculator inputs are processed entirely in your browser and are never transmitted to a server.
There are no advertising trackers, cross-site tracking pixels or third-party marketing cookies.
Optional browser storage is used only for features that improve usability — for example, remembering your recently used calculators and your colour-scheme preference.
You can clear this local data at any time from your browser settings, or via the "Clear" link next to the recently-used list on the homepage.

For full details, see our Privacy Policy.

Accuracy and limitations

We take accuracy seriously. Every formula module is covered by automated unit tests with known inputs and expected outputs, and financial calculators are additionally checked against standard reference examples.

That said, no calculator can replace professional judgement. Please keep the following in mind:

Financial tools use general formulas. Tax treatment, mortgage rules and investment products vary by country and provider, so results are estimates, not offers or guarantees.
Health tools are educational estimators. They do not diagnose conditions and are not personalised medical advice.
Engineering and construction tools produce estimates based on the inputs you provide. Always verify critical values and follow local codes and standards.
Unit conversions use internationally recognised factors, but rounding in intermediate steps can still produce tiny differences.

Disclaimer: Daily Calculator provides general-purpose estimation tools. Results are illustrative and should not be used as the sole basis for financial, medical, legal or engineering decisions. Consult a qualified professional for advice specific to your situation.

Accessibility and performance

Accessibility and performance are design constraints, not afterthoughts. The site is built with:

Mobile-first responsive layouts that work from 320 px phone widths upward.
Semantic HTML landmarks, visible focus indicators and keyboard-accessible navigation, search, menus and calculator forms.
ARIA live regions on result panels so screen readers announce updates.
Colour choices that meet WCAG 2.1 AA contrast targets.
No blocking third-party fonts, no autoplay video and no large decorative image libraries.
Support for prefers-reduced-motion and prefers-color-scheme.

Performance targets are in the "good" range on Core Web Vitals for LCP, INP and CLS. Actual measured scores depend on the device, network and browser in use.

Independence and funding

Daily Calculator is not affiliated with any bank, brokerage, insurer or healthcare provider. The site is not sponsored by a vendor whose products appear in any calculator, and no input values are shared with third parties.

The project is maintained as a small, self-funded effort. If a feature is missing or a result looks wrong, please tell us via the contact page — feedback from real users is the best way to keep the toolset useful.

Contact

For corrections, suggestions, bug reports or general questions, please use the contact form. We read every message.