1. Our Commitment

MolecularWeightCalculator.org is built for students, teachers and professionals everywhere — including users who rely on screen readers, keyboard navigation, magnification, voice control or other assistive technologies.

We believe a free educational resource that some people cannot use isn’t truly free. Accessibility is therefore a design requirement on this Site, not an afterthought — and this commitment covers every current tool and every tool we add in the future.

2. Standards We Follow

We aim to conform to the Web Content Accessibility Guidelines (WCAG) 2.1 at Level AA, published by the W3C’s Web Accessibility Initiative. These guidelines rest on four principles — content must be:

• Perceivable — information can be seen or heard by everyone, with text alternatives where needed;
• Operable — everything works with a keyboard, not just a mouse;
• Understandable — clear language, predictable behavior, helpful error messages;
• Robust — compatible with current and future assistive technologies.

3. Accessibility Features of This Site

4. Accessibility in Our Calculators

Interactive tools need extra care beyond static content. Our calculators include:

• Labeled inputs: every field has a programmatically associated label — screen readers announce exactly what each input expects;
• ARIA roles and states: mode tabs use proper tab/tabpanel roles with selection states; results regions use aria-live so new results are announced automatically;
• Clear error messages: invalid formulas produce specific, spoken-aloud alerts (via role="alert") — never a silent failure or a color-only cue;
• Data in real tables: results render as proper HTML tables with header cells, so screen readers can navigate rows and columns meaningfully;
• Text alternatives for graphs: every visual bar graph is accompanied by the same data in table and percentage-text form — nothing exists only as a picture;
• Multiple output formats: copy, CSV, TXT and print exports let you take results into whatever environment works best for you.

5. Assistive Technology Compatibility

The Site is built with standard, semantic HTML and is designed to work with:

• Screen readers: NVDA and JAWS (Windows), VoiceOver (macOS/iOS), TalkBack (Android);
• Keyboard-only navigation and switch access devices;
• Screen magnification software and high-contrast/forced-colors modes;
• Voice control software (e.g. Voice Access, Dragon).

We recommend using the latest version of your browser and assistive technology for the best experience.

6. Helpful Browser & Device Settings

A few built-in settings that pair well with this Site:

• Zoom: Ctrl/Cmd + Plus to enlarge everything — our layout adapts;
• Reader mode: our articles work well in Firefox/Safari/Edge reader views;
• High contrast: Windows High Contrast / forced-colors mode is respected;
• Reduced motion: if your OS requests reduced motion, animations are minimal and non-essential anyway — no information is lost without them.

7. Known Limitations

Honesty over marketing — areas we’re still improving:

• Chemical notation: screen readers may read a formula like H2O as “H-two-O” rather than chemically ideal phrasing; we’re evaluating better markup for formula pronunciation;
• Complex data tables: very wide comparison tables require horizontal scrolling on small screens — all data remains reachable, but we’re exploring stacked mobile layouts;
• Third-party elements: ads or embedded content, where present, may not meet our internal standards (see Section 8).

8. Third-Party Content

Some content is served by third parties — for example advertising networks or linked external sites (IUPAC, NIST, PubChem). We cannot fully control the accessibility of third-party content, but we choose reputable providers and keep third-party elements to a minimum. Our own tools and articles never require interacting with third-party content to work.

9. Ongoing Efforts

• Accessibility checks are part of our tool development process — keyboard and screen reader passes before every launch, per our Editorial Policy;
• New features are designed with WCAG 2.1 AA as a requirement, not a retrofit;
• User-reported barriers are treated with the same priority system as errors under our Corrections Policy — barriers that block task completion get fixed first;
• This statement is reviewed and updated as the Site evolves.

10. Report an Accessibility Barrier

If any part of this Site is difficult or impossible for you to use, please tell us. It helps to include: the page URL, what you were trying to do, the assistive technology or browser you use, and what happened. We acknowledge reports within 24–48 hours and prioritize fixes that block core functionality.