Amazon / Utilities / CHEMICAL/ENGINEERING TOOLS - CHEMMATHSDROID FREE VERSION
REVIEW
ChemMathsDroid is a working engineer's pocket reference, not a polished one.
A free chemical and process-engineering calculator from a tiny developer that bundles dozens of single-purpose tools into one app — useful, dense, and visibly built by someone who has actually solved the problems it solves.
BY THE APP COMRADE DESK · MAY 10, 2026 · 4 MIN READ
Chemical/Engineering Tools - ChemMathsDroid Free Version
CHEMENG SOFTWARE DESIGN
OUR SCORE
7.0
AMAZON
★ 5.0
PRICE
Free
Most utility apps on the Amazon Appstore aim wide and land shallow — flashlights, unit converters, ten-in-one toolboxes that do nothing in particular very well. ChemMathsDroid does the opposite. It aims at a tiny audience, hits it, and looks like it hits it.
The audience is the chemical or process engineer, often a student, occasionally a working professional, who needs a quick answer to a question with a known formula and doesn’t want to open a spreadsheet, find a textbook, or hunt down a web calculator. The app bundles dozens of those formulas behind a list of buttons. Most users will only ever touch four or five of them. That is the point.
What makes it worth the install on a Fire tablet specifically is that there is almost nothing else in this category. Engineering reference utilities on Amazon’s store are thin on the ground, and the ones that exist either cost more or do less. ChemMathsDroid is free, deep in its niche, and made by someone who clearly cares about the formulas.
The interface looks like a 2014 utility because it is a 2014 utility, but the formulas behind the buttons are the ones a junior process engineer actually reaches for.
FEATURES
ChemMathsDroid Free is a sprawling collection of small calculators wrapped in a single Fire-tablet utility. The menu is essentially a list: pipe sizing, pump head and NPSH, heat-exchanger sizing, control-valve Cv, vessel volumes, flange ratings, conversion tables, periodic-table lookups, basic thermodynamic property estimators, and a long tail of formula references for chemical, mechanical, and process engineering coursework.
Each tool is a form. You type in the inputs you have, the app returns the number you want, and that's the entire interaction. There are no projects, no saved sessions, no cloud sync, no account. It is a calculator app in the literal pre-smartphone sense — pick a function, run it, close the app.
The free version is gated against the paid ChemMathsDroid Pro, which unlocks the full set of tools and removes ads. The free build still covers enough of the common process-engineering calculations to be useful as a check-your-work companion in a lecture hall or on a plant walk.
MISSION ACCOMPLISHED
The breadth is the win. There is no other free Fire-tablet app that covers this much chemical-engineering surface area in one place, and the developer is clearly a working engineer rather than a generalist app shop — the choice of which formulas to include and which units to default to reads like someone who has actually had to look these up at a desk.
For students, it is a genuinely cheaper alternative to dragging a Perry's Handbook around. For working engineers, it is a sanity check you can run on a tablet during a meeting without opening a spreadsheet.
ROOM TO IMPROVE
The interface is rough. Layouts are dense, typography is small, and on a Fire HD 10 the input fields sit in the middle of large grey blocks of unused space. There is no dark mode, no landscape optimisation worth mentioning, and the navigation between tool categories relies on a long scrolling list rather than search.
The free build also leans on ads between calculations, which interrupts the flow when you are working through a problem set. The Pro version removes them, but the upgrade prompt itself is one of the more frequent interruptions.
CONCLUSION
Install this if you are a chemical, process, or mechanical engineering student with a Fire tablet, or a working engineer who wants a free formula reference on a device that isn't your phone. Everyone else will find it impenetrable, which is fine — it isn't trying to serve everyone else.