Your sums are yours. Slate keeps your settings and calculation history on your device. There are no accounts and nothing to sign in to.
Slate uses the network for Exchange's published reference rates, for the store's billing for the one-time purchase, and for casting to your TV if you use it.
The calculator tools work offline: everything ships inside the app. Read the privacy page →
Why it exists
Everyone's phone has a calculator. Almost nobody likes theirs. And the everyday jobs - a discount, days between dates, splitting a bill, GST on a quote, what that is in another currency - end up in a browser tab, or a guess.
Slate gathers those jobs onto one board, dressed in chalk on slate. Every tool runs on the same skinned keypad, the keys click like they mean it, and the system keyboard never appears.
Thirty seconds with Slate
The chalk board, the tools and the skins, in half a minute. The spot lives on YouTube; nothing plays or loads from this page.
The presenter in the spot is AI-generated. Everything else is the real app.
Eight tools, one keypad
Calculator, Percent and Date are free, and complete. The other five are part of Slate Pro, one purchase, no clock.
Calculator
Basic for everyday sums, and one tap opens the scientific keys: trig and inverses, logs, roots, powers, factorials, π and e, degrees or radians. Percent works the way desk calculators always have: 50 + 10% is 55. The tape above the display remembers recent results; tap one to use it again.
Percent
Discounts, markups, and tip-of-the-tongue "what percent of what" sums.
Date
Days between dates, add or subtract days, work out an age.
Tip Pro
Split the bill fairly, down to the cent.
Units Pro
Length, weight, volume, temperature and more.
Loan Pro
Repayments and total interest at a glance.
GST Pro
Add it to a quote or pull it out of a total, at any rate.
Exchange Pro
Convert currencies on published reference rates, and keep the last table on the phone.
Every sum remembered
Slate keeps the calculations you finish, newest first. Tap one and it loads straight back into the tool that worked it out, ready to change. Clearing the list is two taps.
Skins that change everything
Slate ships in chalk. Slate Pro re-dresses every tool: Ledger's paper and ink, Terminal's green phosphor glow, Porcelain's clean white, Ember's warm coals, Drift's dusk violet, Blueprint's cyanotype lines.
Every skin pairs with its own key sounds: Typewriter, with a carriage bell on equals, then Beeps, Droplets, Woodblock, Hush and Abacus. The gallery below shows five of the skins at work.
Cast it
Put your working on the big screen: cast to a TV and Slate mirrors whichever tool is up, same numbers, same skin, while your phone stays the keypad. Walk away and an idle cast tidies itself up after a few minutes.
Casting needs the internet: your TV loads Slate's display page from our studio site, zone7studios.com, and casting uses Google's Cast framework, which is covered by Google's privacy policy.
What it looks like
The chalk board, and five of the skins at work: six screens from the Google Play listing, captured from the release build on a phone.
Pay once, own it
Slate is complete without paying: the full basic and scientific calculator, Percent, Date, the tape, the history, the chalk board and its key sounds.
Slate Pro is a single one-time purchase that unlocks the other five tools and every skin and sound set, including the ones we add later. Pay once, own it forever, and no subscription, ever.
What Slate will never do
Not settings you have to find and switch off. Not in the app at all.
- Ask for an account or a sign-in
- Carry an ad, or an ad SDK
- Charge you weekly, monthly or yearly
- Upload your sums anywhere
- Pop up the system keyboard
- Beg you for a rating
- Interrupt you with an upsell
Slate keeps your settings and calculation history on your device. The Exchange tool fetches published reference rates when you open it, and it sends nothing about you when it does. The privacy page has the detail →
Get Slate
Slate is on Google Play. Tap the badge to install: Calculator, Percent and Date are yours from the first tap, and Slate Pro is one purchase inside the app. The iPhone build is real and in testing; it has no date yet.
There's nothing to sign up for here: no mailing list, no email box, no “notify me”. Zone7 doesn't email people, and that starts with this page.
From the same maker
Slate is a Zone7 Studios app, with the same quiet-software rules as the rest of the family: private by design, no ads anywhere, and nothing that treats your attention as inventory.