Support

We answer every email, usually within a day.

How does the Chalk Pro subscription work?

Chalk Pro unlocks all 16 trade calculators and saved projects. It's an auto-renewing subscription — $2.99/week or $17.99/year — billed to your Apple ID and handled entirely by Apple. There's no free trial; the free tier (fraction calculator, unit converter, check square, pitch & slope, area & volume) stays free without subscribing.

How do I cancel my subscription?

Subscriptions are managed by Apple: iPhone Settings → your name → Subscriptions → Chalk → Cancel. You keep Pro until the end of the period you've paid for, and you won't be charged again.

How do I restore my purchase on a new phone?

Open Chalk → Settings → Restore Purchases, making sure you're signed into the same Apple ID you originally subscribed with. Your Pro access comes right back — no receipts to dig up.

How do I switch between metric and imperial?

You usually don't need to — every result is shown in both systems at once, and you can enter values in either (or mix them in one calculation) using the unit keys on the keypad. To change which system is shown first, use the unit preference in Chalk's Settings.

How do I change the fraction precision?

Chalk Settings → Fraction precision. Choose 1/8", 1/16", 1/32", or 1/64" — results round to the increment you pick, so the display matches your tape and the tolerance of the work. Internally, fractions stay exact.

Does Chalk work offline?

Yes, completely. Every calculator, diagram, and saved project runs on-device with no account and no signal — airplane mode included.

Can I rely on the results?

Chalk's results are estimates from the values you enter. Always double-check dimensions and quantities against your plans and local codes, and confirm structural work with a qualified professional before you cut, pour, or order. See the Terms of Use.

Something else?

Write to support@chalkcalc.com — bug reports and calculator requests genuinely shape the roadmap.