Smythy / Electrical calculators
Calculator questions
Choosing a method, saving a result and returning to your work.
Calculator questions
Start here for questions about using Smythy. For a particular calculation, read the method and assumptions beside the result.
New to the tools? Try a worked example, or read the calculator guidance before choosing a method.
All Smythy calculators are free to use. Open a tool and enter your inputs. You can calculate and download a watermarked PDF without an account or email subscription.
Use voltage drop to check the drop for a known conductor size, or find a Table C8 size for a chosen drop limit. Use cable sizing to compare copper V-75 sizes with current capacity, installation conditions and voltage drop considered together. A size found from voltage drop alone still needs the other installation checks.
Voltage drop and maximum demand use the stated AS/NZS 3000 methods. Copper V-75 cable sizing uses the listed AS/NZS 3008.1.1:2025 data. Other tools use the method named on their page, including simplified or educational models where indicated. Check each tool’s scope against the licensed standard and the installation.
No. Each calculator answers a stated question within its assumptions and limits. Review the calculation against the actual installation, equipment data and applicable standards. A result or PDF is a calculation record, not installation certification.
After calculating, choose Download PDF to keep the inputs, results and method in a watermarked record. PDF generation needs an internet connection. You can also use the tool’s print control. The export flow asks you to accept the calculator Terms.
The calculator library shows recent runs kept in this browser on this device. Reopen a run to return to the tool. These records do not sync between devices and can be removed when browser data is cleared, so download a PDF for calculations you need to retain.
Yes. Use the same tools in a recent phone, tablet or desktop browser. You can also add Smythy to your home screen for quick access.
Most tools calculate in your browser once the page has loaded. Maximum demand, some engineering tools and all PDF exports use the server and need a connection. Do not rely on an unvisited page being available offline.
Check the units, defaults and method first. For a cable run, check the one-way route length, circuit type and conductor size. If the result still differs from what you expect, email [email protected] with the tool name, inputs, result and any reference you used.
The optional email list is for new calculator announcements. Confirm your email to join; every announcement includes an unsubscribe link. Subscribing is separate from using the calculators.
Need help with a result?
Contact support with the calculator name, your inputs and the result you expected.