sparkytools

Printable formula sheets

Pocket references you can print or save as a PDF straight from your browser — no email, no sign-up, nothing to install. Every sheet is built from public mathematics and physics: the arithmetic relationships, not code-book data. When you need a value that lives in the code — an ampacity, a fill, a box volume — that stays in your code book, on purpose.

Which sheet, when

Bending multipliers & shrink lives in the bender bag. You will have the 30° multiplier memorised inside a week; it is the shrink per inch and the odd angles you reach for the card on. When you want the actual pull worked out rather than the table, that is bentright.com.

Ohm's law & power wheel goes on the inside of the locker door, where you see it every morning until you stop needing to. Cover the quantity you want; what is left is the formula.

Fraction / decimal / mm chart is the one to tape to the tape-measure case. Every sixteenth as a decimal and in millimetres, for the day a drawing is metric and your tape is not.

Single & three phase formulas is for the level exam: power, kVA and the motor-current formula, single and three phase, with one load worked both ways so you can see why the three-phase current comes out smaller.

Trade math cheat sheet is the night-before sheet: right triangles, area, percent and the conversions, on one page, next to the drills that practise each of them.

Sheets to work, not just read

These are references. For problems to work with a pencil, the printable worksheets give twelve at a time — Ohm’s law, voltage drop, series and parallel, trade math and motor control — with the answer key and its working on a page of its own.

Printing a pocket card

Print at two pages per sheet, or at 50% scale, and the sheet lands at a size that folds twice into a shirt pocket. Fold it, then laminate it with clear packing tape on both sides — it costs nothing and the card survives a season in a bag with the bender. The print button on each sheet opens your browser's own print dialog; choose "Save as PDF" there if you want a file for your phone instead. The site chrome drops away so the sheet comes out clean either way.

What is deliberately not on any sheet

No ampacities, no conduit or box fill limits, no motor full-load values, no derating factors, no conductor colours. Those are the code book's, they come with conditions attached, and they change with the edition — a card printed under one code cycle is quietly wrong under the next. The sheets here carry only the relationships that do not change: the trigonometry of a bend, Ohm's law, the arithmetic of a fraction, the physics of power. When a sheet reaches the edge of one of those and needs a value from the book, it says so and leaves the space for you to write yours in.

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