CalcOS · by Indus Apps

Every calculation, in one app.

CalcOS is an all-in-one toolkit of 100+ calculators, converters and everyday utilities for iOS and Android — fast, organised and private. The only calculation app you'll need on your home screen.

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100+Tools in CalcOS
iOS · AndroidBuilt for both
1 → manyA growing family
100+ tools
one tap away
Instant
offline-first
Private
no account
9:41
Good afternoon 👋
CalcOS
Search 100+ tools…
Recently UsedSee all
Loan EMI
BMI
Convert
Interest
Quick ToolsSee all
Finance
Loan EMI

Monthly EMIs & amortization for any loan.

Health
BMI Calculator

See your body mass index instantly.

Home
Categories
Favourites
Settings
Why CalcOS

One app instead of twelve. CalcOS brings every calculator, converter and utility you actually reach for into a single, beautifully organised place — so you can stop hunting the store for a one-off tool you'll use once.

01

Everything in one place

100+ tools across finance, health, math and conversions — sorted by category, with recents and favourites at your fingertips.

02

Fast & offline

Results the moment you type. No spinners, no accounts, no connection required — everything runs on your device.

03

Private by default

Your numbers never leave your phone. No sign-up, no tracking of what you calculate. Just the tools you need.

Flagship product

One app.
A hundred tools.

CalcOS is an all-in-one toolkit of calculators, converters and everyday utilities — organized, fast, and private. It's our first product, and the proof of how we build.

100+ tools, one place

Finance, health, math, conversions and more — the calculations you reach for, without hunting through a dozen apps.

Instant & offline-first

Results the moment you type. No spinners, no round-trips — everything runs on-device.

Cleanly organized

Tools sorted by category, recents at your fingertips, favourites you choose. Breadth without the clutter.

Private by default

No sign-up, no tracking of your numbers. Your data stays on your phone, where it belongs.

100+
Tools & growing
12
Categories
0
Sign-ups needed
9:41
Categories
Explore
Search 100+ tools…
18
Finance

Loans, interest, tax & savings.

14
Health

BMI, calories, body metrics.

22
Converters

Length, weight, units & more.

16
Math

Algebra, geometry, equations.

Home
Categories
Favourites
Settings
Why you'll keep it

A calculator app that feels calm, fast, and quietly powerful — one that respects your time and disappears into everyday life.

No clutter, no accounts, no noise. Just the tools you need, organised the way you'd expect, ready the moment you open the app.

Thoughtful design Real utility Offline-first Private
From the studio

CalcOS is built by Indus Apps.

An independent mobile studio crafting its own products for iOS and Android. CalcOS is the first — with more apps on the way, each held to the same standard.

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How we build

A studio built for product discipline.

01

Mobile-first thinking

We design for the phone first — the device people actually reach for — not a desktop layout squeezed down.

02

Fast iteration

Small, focused releases. We ship, learn from real use, and refine — instead of guessing behind closed doors.

03

Polished UX

Motion, spacing and copy tuned until the app feels effortless. Polish isn't decoration — it's the experience.

04

Utility-driven

Every feature earns its place by solving a real problem. If it isn't useful, it doesn't ship.

05

Product discipline

A shared design system and clear standards keep every Indus app consistent, coherent and unmistakably ours.

06

Premium interface design

Restraint, hierarchy and craft — interfaces that feel considered, calm and genuinely high-end.

Rooted in mobile

Built for real hands,
real moments, real use.

CalcOS lives where life happens — in a pocket, mid-task, one-handed. It's built for real behaviour on both iOS and Android, so it feels native, quick and right at home on your device.

Built for
iOS
Built for
Android
One-handed
reachable, tap-friendly targets
Instant launch
tool ready before you look up
0.2s
Works offline
no signal, no problem
Get CalcOS

Your toolkit,
ready when you are.

CalcOS is coming to iOS and Android. Join the list for launch access and updates, or reach out — we'd love to hear what you'd like to calculate.

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No spam, ever. Or email us directly at corporationsindus@gmail.com