About KLM Labs

KLM Labs is a small app studio run by its founder, Mayank Kumar Grover. We make focused iPhone and iPad apps for tradespeople, contractors and one-person businesses, and a few for everyone, and this site, with each app's facts and free templates and charts made with the apps.

Who we are

KLM Labs is a one-founder studio. Mayank Kumar Grover founded it and runs it; the App Store lists our apps under his name, on his developer page.

What we make

• Invoice Maker: invoices and estimates on iPhone and iPad, offline and with no account.
• Construction Calculator: feet, inches and fractions done exactly, plus stairs, roof pitch, rafters and concrete.
• Flip Clock: a big flip, digital or retro LED clock for your nightstand or desk, with alarms that ring on Silent.

Each app’s page says what it does and what it doesn’t, and lists its plans and prices as the App Store shows them. The free pages are invoice templates by trade and printable construction charts.

How the templates and charts are made

• Invoice templates. Each sample invoice is printed by Invoice Maker’s own PDF layout. The layout code is copied unchanged from the version on sale on the App Store, and every build checks that the copy hasn’t been edited. The amounts on a template’s page are the ones its PDF prints. The businesses, people and figures in the samples are made up.
• Construction charts. Every number in a chart is worked out by Construction Calculator’s own formulas, taken from the version on sale and held to the app’s own test results. Before a chart page goes live, a script works out every row of every table again and compares it cell by cell.
• Building codes. Where a page gives a code limit, such as the stair riser and tread limits in the 2021 International Residential Code, it names the section and links the code text it was read from. Towns and states adopt and amend these codes, so check the code your building department uses.

How we check each page

We write the pages with the help of AI models. Before a page goes live, a second model reviews it, and scripts check every link, price and chart number. They also check each app’s facts against Apple’s public app lookup and its App Store page: name, version, size, price, languages and plans. Each page lists its sources and the day it was last updated, and each app’s page shows the day its facts were checked against the App Store.

Corrections

If something here is wrong, such as a price, a fact about an app, a number in a chart or a code reference, email support@klmlabs.app with the page’s address and what you found. We check it against the source. If the page is wrong, we fix it and change its “last updated” date.

Every other address is on the contact page.