I recently uncovered a super simple calculator website that’s making around $36,000 per month — and honestly, it blew my mind.
What’s even crazier is that this site is so niche and so simple, yet 1.6 million people use it every month.
Naturally, I started wondering: what other simple calculator websites are also making big money?
Today, I’ll break down four calculator websites:
How much money they make
Where they get their traffic
And how they are turning simplicity into big profits
Plus, the final site I’ll reveal is ranked as the 92nd highest-traffic website in the world.
Let’s dive in and crunch the numbers!
First up is SleepCalculator.com.
When I first heard about it, I assumed it might have some complex sleep algorithm.
But no — it simply asks you when you want to wake up and tells you what time you should go to bed.
It also shows you how many sleep cycles you might go through.
That’s it. Just basic bedtime math.
Yet, 1.6 million people use it every month!
According to SimilarWeb:
Monthly Visitors: 1.63 million
Page Views per Visitor: 1.48
Where does the traffic come from?
A lot comes from direct and repeat visitors
Plus, a strong amount from Google organic traffic — nearly 600,000 organic visitors per month
(people searching for terms like “sleep calculator,” “what time should I go to bed,” and “REM cycle calculator”).
The site makes money through Google display ads — including banner ads and even full-page interstitial ads.
Estimated Earnings:
Assuming a $15 RPM (since sleep-related terms are valuable),
SleepCalculator.com likely makes around $36,600 per month.
Next up is SnowDayCalculator.com.
This site predicts whether schools will have a snow day tomorrow.
You enter your ZIP code, how many snow days you’ve had so far this year, and it gives you the odds.
Simple concept — but it turns out, a ton of people use it, especially during winter!
According to SimilarWeb:
Monthly Visitors (in peak winter): 2.9 million
Page Views per Visitor: 2.19
The traffic is very seasonal — mainly peaking from December through February.
Popular search terms include “snow day calculator,” “snow day predictor,” and “chance of snow day.”
Just like SleepCalculator, it makes money through display ads.
Estimated Earnings:
With a conservative $7 RPM, during peak winter months,
SnowDayCalculator.com likely makes over $44,000 per month.
Next is something more mysterious: Gematrix.org.
This site is all about gematria — assigning numerical values to letters and words, a practice linked to Jewish mysticism, numerology, conspiracy theories, and curiosity about hidden meanings.
You input a word or number, and it shows you associated values and similar words.
At first, I didn’t even know what gematria was — I had to ask ChatGPT!
But apparently, over 622,000 people visit this site every month.
According to SimilarWeb:
Monthly Visitors: 622,000
Page Views per Visitor: 6.13 (very high engagement!)
Popular search terms include “gematria calculator,” “Hebrew gematria calculator,” and “gematria decoder.”
And yes — the site runs display ads all over the place.
Estimated Earnings:
At a conservative $5 RPM,
Gematrix.org could be making around $119,000 per month.
Finally, we have the big one: Calculator.net.
This site offers every calculator imaginable:
Mortgage calculators
Auto loan calculators
BMI calculators
Scientific calculators
GPA calculators
Age calculators
And more
It’s not a small operation — this is a calculator empire.
According to SimilarWeb:
Monthly Visitors: 48.8 million
Page Views per Visitor: 3.49
Global Traffic Rank: 912th most visited site in the world
Estimated Earnings:
With 170 million monthly page views and a conservative $5 RPM,
Calculator.net could be making around $851,000 per month — and potentially double that with a $10 RPM.
These examples show that simple ideas can turn into major businesses when done right.
✅ Solve a specific problem.
✅ Rank for the right keywords.
✅ Monetize with simple display ads.
If this inspired you, maybe it’s time to think about:
Adding a simple calculator to your own website
Or brainstorming a new niche calculator idea!
Thanks again for reading!
