About Calculator Star

Mathing at the Speed of Voice

Calculator Star uses voice to help you solve complex everyday math questions in a matter of seconds.

I believe that getting an answer shouldn’t require navigating complex menus or typing out long equations. Whether you are checking homework, comparing prices at the grocery store, or figuring out a tip, just ask.

What Can You Ask?

Calculator Star is designed to handle the real-world math scenarios you face every day. Here is how it solves them:

Mathing with your child

"We are buying apples for your school lunches. If you eat one apple every day for five school days, and each apple costs 60 cents, how many apples do we need to buy in total? Can you help me figure out the total cost?"
= 5 apples, Total $3
Logic:
  • Calculate total apples: 1 apple/day × 5 days = 5 apples.
  • Calculate total cost: 5 apples × $0.60 = $3.

Mathing for deals

"This $80 jacket is on sale for 25% off; what is the final price?"
= $60
Logic:
  • Calculate discount amount: $80 × 0.25 = $20.
  • Subtract discount from original price: $80 - $20 = $60.

Mathing in Physics

"Calculate the escape velocity from Mars. Mass is 6.4 × 10²³ kg, Radius is 3390 km."
= 5019 m/s
Logic:
  • Formula: vₑ = √(2GM/R)
  • Constants: G ≈ 6.674 × 10⁻¹¹
  • Conversion: R = 3390 km = 3.39 × 10⁶ m
  • Calculation: √(2 × 6.674e⁻¹¹ × 6.4e²³ / 3.39e⁶) ≈ 5019 m/s

Mathing for food

"The recipe calls for 2/3 cup of flour for 4 people, but I'm cooking for 6. How much flour do I need?"
= 1 cup
Logic:
  • Calculate the scaling ratio: 6 people ÷ 4 people = 1.5.
  • Adjust ingredient: 2/3 cup × 1.5 = 1 cup.

Mathing for trips

"If I drive 200 miles at an average speed of 65 mph, what time will I arrive?"
= 3 hrs 5 mins
Logic:
  • Calculate duration in hours: 200 miles ÷ 65 mph ≈ 3.08 hours.
  • Convert decimal hours to minutes: 0.08 × 60 ≈ 5 minutes.

Mathing in other languages

"苹果5元一斤。我要买2公斤，一共多少钱？"
= 20元
Logic:
  • 单位换算：1公斤 = 2斤
  • 数量：2公斤 × 2 = 4斤
  • 总价：4斤 × 5元 = 20元

Why a Dedicated App?

You might wonder, why not just use a general AI chat app? You certainly could, but I believe that constraints matter.

General AI chatbots are designed to do everything, which can sometimes make them slow or overly complex for simple tasks. Calculator Star is laser-focused on one thing: solving everyday math problems instantly and accurately. I believe you build the best tool when you focus on something very specific.

Currently Supported

  • Languages: You can ask questions in 5 languages (English, Chinese, Spanish, French, and Japanese). You can switch your preferred language anytime in the settings. I may support more languages in the future.
  • Beta: Calculator Star is very new, so there will be bugs. Please report them to me, and I will try to fix them as soon as possible. The app is currently completely free. If more people start using the app and I need more support to keep running it, I may charge in the future, but that is not the goal right now.

Who is behind Calculator Star?

Hi, I’m Kevin Ho. I am a product designer and entrepreneur based in the Bay Area (co-founder of Glow, previously Google and Slide).

I initially created this app for my daughter to help double check her math homework (she’s in the third grade). Then I found that her classmates’ parents also wanted something like this, so I decided to polish it up and release it into the wild.

Data science is what I have always loved, and I do see a world where Calculator Star can evolve into something much bigger in the future. Because I believe there is a need for a truly intelligent computational engine. One that understands context, nuance, and language just as well as it handles raw numbers. Perhaps the aspirational goal is to build the world’s smartest calculator, capable of solving any math or physics problem you can voice. But for now, it’s just day 1.

Have fun and DM me on X @kho to let me know how I can improve it!