Frequently asked questions

Kalku is not in the stores yet. When it is, the buttons on this site will take you straight to the App Store and Google Play. Until then, the free calculators on this site run the same formulas in your browser.

Yes. Kalku has no ads, no subscription and no in-app purchases, and it never asks you to sign up for anything.

iPhone and iPad with iOS 15 or later, and Android phones and tablets with Android 7.0 or later. On a tablet the history sits beside the keypad. The app is laid out for portrait.

Yes, all of it. Every calculator, the 3D previews, your saved calculations and sharing as PDF work with no connection, which is the point on a jobsite. Nothing in the app needs the internet.

Yes. Kalku has a metric mode, and in either mode you can enter and convert to millimetres, centimetres, metres, square and cubic metres, kilograms and metric tons as well as feet, inches, yards, acres, board feet, gallons, pounds and tons. Numbers can use a decimal comma and thousands separators, and any currency symbol.

The way a dimension is written on a drawing. Type 20 Feet 6 Inch 1 / 2 and the display reads 20' 6-1/2". Digits after a unit key belong to the next unit down, so 20 Feet 6 already reads as 20' 6". Answers are rounded to the fraction you choose, from 1/2 to 1/64 of an inch, and shown as 20' 6-1/2", 20'-6 1/2" or 20 ft 6 1/2 in.

Ready-made forms in 14 categories: project dates and times, business, concrete, foundations, framing, roofing, floors, walls and ceilings, masonry, paving, electrical, heating and air conditioning, plumbing, shapes and geometry, and conversions. Every figure updates as you type, each calculator shows its formula and assumptions underneath, and you can search them by name or by the trade's own words.

Any calculation, from the keypad's history or from a calculator, can be saved with a name and a note in the Saved tab, and shared as a clean PDF with every input and result, or as plain text, through your phone's share sheet. That includes printing and sending it to a client.

The arithmetic is exact to the precision shown, and every calculator is covered by tests against known answers. The results are still estimates for ordering and layout: they rely on the figures you enter and on typical trade values, such as a bag's yield or a paint's coverage, that you can change. They do not replace your local building code, the manufacturer's data or an engineer.

Kalku has no account and no ads, and what you enter and save stays on your phone (and in your phone's own backup, if you use one). It sends anonymous usage statistics and crash reports to my own analytics server, with no identifier for you or your device, and you can turn them off in Settings > Privacy. The privacy policy lists exactly what is sent.

38: English, Afrikaans, Arabic, Azerbaijani, Belarusian, Bulgarian, Czech, Danish, German, Greek, Spanish, Finnish, French, Hebrew, Hindi, Hungarian, Indonesian, Icelandic, Italian, Japanese, Kazakh, Korean, Malay, Norwegian, Dutch, Polish, Portuguese, Romanian, Russian, Slovak, Swedish, Thai, Turkish, Ukrainian, Uzbek, Vietnamese, and Chinese (Simplified and Traditional). It follows your phone's language unless you pick one in Settings. This website is in English.

1. Go to the report page.
2. Fill in the form and send it.
3. I will respond via email.

On iOS/iPadOS/macOS:

1. Hold the app icon on your home screen and tap the delete icon.
2. Or go to Settings → General → iPhone Storage, select the app, and tap Delete App.

On Android:

1. Hold the app icon and drag it to the uninstall icon.
2. Or go to Settings → Apps, select the app, and tap Uninstall.

Disclaimer: if your data isn't saved to the cloud, it will be lost — data is stored locally on your device.

Some basic troubleshooting steps:

Restart the device (no data lost):

• Hold the power button and slide to power off.
• Wait 10 seconds, then turn it back on.

Clear cache or reinstall (data will be lost — back it up first):

• On Android: Settings → Apps → select the app → Clear cache / Clear data.
• On iOS/iPadOS/macOS: delete the app and reinstall it from the App Store.

1. Open the App Store or Play Store.
2. Go to the updates section.
3. Find the app and tap "Update".

1. Open the app and go to Settings.
2. Select "Language".
3. Choose your preferred language from the list.

Roughly every 2-3 weeks, depending on the app.