Available on iOS and Android

Mental math. For life.

Times tables, fractions, percentages, algebra. From the middle school student to the adult staying sharp. 10 minutes a day.

From middle school to adult. No ads, no data collection.
Kalc app on iPhone: dashboard showing progress per mental math skill.
8
Math skills
94
Exercise types
12+
Ages covered
100%
Offline

Built to actually move you forward

Not a game in disguise. A training tool, calibrated to your level.

Adapts to you, not the other way around

A short calibration at the start picks up your real level. Exercises unlock at your own pace, level by level, skill by skill. Maps to UK Year 7-10, US Grade 6-9, or fully unlocked for adult self-learners.

Addition
Multiplication
Division
Fractions
Percentages
Order of operations
Powers
Algebra

Spaced repetition that thinks ahead

A system based on the forgetting curve brings back what you were about to forget, right when you need it. You consolidate instead of drilling on autopilot.

See your progress

XP, day streak, level per skill, last week's sessions. A widget on your home screen. Concrete data, no marketing fluff.

About Kalc

A mental math training app

Kalc is an iOS and Android app based on spaced repetition (SRS). Two profiles: students aged 12-15 (UK Year 7-10, US Grade 6-9, plus French and Spanish-speaking systems) with full curriculum coverage, and adult self-learners with all skills unlocked.

Covers 8 math skills across 94 exercise types, with day-to-day examples adapted to each profile.

Published by LMT Digital Creations

Frequently asked questions

Can't find your answer? Write to us at info@kalc-app.com.

What is mental math?
Mental math means solving arithmetic in your head, without a calculator and without writing it down. Times tables, fractions, percentages, order of operations, powers, algebra. A skill used every day: splitting a restaurant tab, working out a discount, checking a paycheck.
What exactly is Kalc?
A mental math training app based on spaced repetition (SRS). Sessions take 10 minutes a day. Concepts you miss come back the next day, ones you master space out over time. Covers 8 skills (addition, multiplication, division, fractions, percentages, order of operations, powers, algebra).
Who is Kalc for?
Two profiles. Ages 12-15 (UK Year 7-10, US Grade 6-9) with full curriculum coverage. Adult self-learners with all skills unlocked and real-life examples adapted to adult context (restaurant tab, paycheck, mortgage, taxes).
How much does Kalc cost?
You can try Kalc for free. Full access unlocks with two options: a one-time lifetime purchase (all future updates included) or a 1-year non-renewing access. No auto-renewing subscription.
How many minutes a day?
10 minutes a day is enough. Below that, the SRS effect doesn't hold. Above that, the marginal gain drops fast. The method is calibrated for this volume.
Any ads or tracking?
None. No banners, no rewarded video, no advertising tracking, no cookies. Everything stays on your device and syncs through your personal iCloud (iOS) or Google backup (Android).