About ElectroCalculators
ElectroCalculators is a set of 32 free, interactive calculators for electronics and electrical engineering. No account, no paywall, no limits, no advertising.
The premise is narrow and worth stating: a calculator is only useful if you can find out how it decided. Every page here names the standard its numbers came from, shows the date it was last reviewed, and belongs to someone you can write to. That is the whole difference between this and a formula typed into a form.
Who reviews the calculators
Technical reviewer
Salamot Hok
Electrician · 10+ years of installation work in Bangladesh and the wider South Asian region
He reads every result the way an installer would, and his review is the practical one: are these the values people actually meet, does the warning fire where you would stop and think, is the answer something you could buy and fit? The code tables themselves come from the published standards cited on each page — a boundary set out plainly on his profile rather than blurred.
How the formulas are verified
Every calculator’s maths lives in a pure function with its own test suite, asserted against worked examples from published references and standards — Horowitz & Hill’s The Art of Electronics, Sedra & Smith’s Microelectronic Circuits, and the relevant IEC, IEEE, IPC and NEC documents. A calculator does not ship until its tests pass.
Where the inputs do not describe a real design, the calculator withholds the number and tells you why. A plausible-looking wrong answer is the worst thing a tool like this can produce, and it is the failure the whole process is built to prevent. The full account is on the methodology and editorial policy page, including what we refuse to publish and what happens when you report an error.
Each page lists its sources and the date it was last reviewed. If you find an error, report it to [email protected] — a wrong formula is the one thing a site like this cannot afford, so those messages are answered first.
Engineering notation
Every numeric input accepts values the way they are written on a schematic. Type 4k7 for 4.7 kΩ, 100n for 100 nF, 2M2 for 2.2 MΩ,20m for 20 mA. RKM codes such as 4R7 work too, as do plain decimals and scientific notation.
Standard component values
Where a calculator produces a component value, it also shows the nearest standard part from the appropriate IEC 60063 E-series and the error that substitution introduces. A design built from E24 parts you can actually buy is more useful than a theoretical value to four decimal places.
Embedding a calculator
Any calculator can be embedded in your own site, course page or wiki. Open the calculator, press Embed, and paste the snippet. Embeds are free to use — we ask only that you leave the attribution link in place.
Privacy
Calculations run entirely in your browser. Input values are never sent to a server. There is no advertising and nothing is sold or shared. Google Analytics sets a cookie only if you allow it on the banner, and it never receives your calculation inputs; the only things stored locally are your theme preference, your analytics choice and any calculations you explicitly save. The details are in the privacy policy.
What this site is not
These calculators are engineering guidance, not a design review, an inspection or a code sign-off. Verify against the governing standard before relying on a result for safety-critical or code-compliance work — the disclaimer sets out the limits in full.
Contact
Corrections, requests for new calculators and embed questions: [email protected], or via the contact page.