NEC 2020 · 2023 · 2026 · fully offline
Every NEC calculation, in the edition your jurisdiction actually adopted.
Seven calculators. NEC 2020, 2023 and 2026. Every result names the table it came from. Works with no signal.
$19.99 once. No subscription. 3 of the 7 are free.
65 A load · copper · 90 °C wire on 75 °C lugs
6 AWG
75 A base, capped at 65 A by 75 °C terminations ≥ 65 A
ref: NEC Table 310.16 · NEC 110.14(C)
The worked example
The answer, and the rule that produced it.
Most calculators print a number and stop. This one prints the number, the table it came from, and the rule that chose it. If the answer changes hands on a job site, the reason travels with it.
65 A load · copper · 90 °C wire on 75 °C lugs
6 AWG
75 A base, capped at 65 A by 75 °C terminations ≥ 65 A
NEC Table 310.16 · NEC 110.14(C)
Golden case WR-01: a published worked example, reproduced exactly by the engine's test suite.
Editions
All three, included.
NEC
2020
still enforced in many states
NEC
2023
most widely adopted
NEC
2026
newest cycle, adoption beginning
Calculators
Seven calculators.
- 01 Voltage DropFree AC/DC · 1φ/3φ
- 02 Wire SizeFree ampacity + derating
- 03 Conduit Fill % fill + jam ratio
- 04 Box Fill volume + allowances
- 05 Breaker / OCPD standard sizes + caps
- 06 Motors FLC + branch device
- 07 Ohm's WheelFree V · A · W · Ω
Why this one
All three code editions
NEC 2020, 2023 and 2026, switchable in two taps. The answers change between editions, and so do the table numbers cited — both follow the edition you pick.
Every result cites its article
The number comes with the table it came from, and with the rule that bound it. You can check the work, and so can the inspector.
Works with no signal
Everything runs on the device. No account, no sign-in, no connection — the basement and the new build are where this gets used.
Nothing you enter leaves this device. There is no account, no tracking and no analytics. The app works with no signal because it never needed one.
Price
$19.99, once.
No subscription. No ads. No analytics. No account.
Free, to check the work first
Voltage DropAC/DC · 1φ/3φ
Wire Sizeampacity + derating
Ohm's WheelV · A · W · Ω
FAQ
Facts & Questions
Why isn’t it free?
Because the free ones are paid for another way. There are no ads here, no subscription, no analytics and nothing to sell — which only works if the people using it are the ones paying for it. Once, and then it is yours.
Which code edition does it use?
Whichever you pick. NEC 2020, 2023 and 2026 are all included, and switching changes both the answers and the table numbers cited — the box-fill volume table alone is numbered three different ways across those editions.
Is my data private?
Nothing you enter leaves the device. There is no account and no tracking of any kind. The only thing that ever leaves is a crash report, and it carries the error and the device model — never what you typed.
Does it work offline?
Entirely. It never needed a connection, so losing one changes nothing.
How is this different from the free calculators?
Two things. Every result names the article and table it came from, and the rule that bound it. And three editions ship, not one — which matters when the edition your jurisdiction adopted is not the newest.
What if a number looks wrong?
Tell me, and include the inputs and the edition. Every table in the app was verified three ways before it shipped and the errata found along the way are published, so a report gets a real answer rather than a support macro.