
LeetCode
Codility
CodeSignal
iMocha
HackerEarth
Codewars
TestGorilla
HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.

Omni Calculator
CalcIQ.app
Calcfort
calculator.net
Calcver
Scientific Calculator
AskYourDatabase
70+ free online calculators for EMI, BMI, Zakat, finance, health, math, construction, and unit conversion. No sign-up. Instant results. 100% free.

Which is more popular?
Based on our record, HackerRank seems to be more popular. It has been mentioned 67 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | hackerrank.com | calcsphere.org |
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What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
HackerRank is recommended for students, individual learners, and job seekers looking to improve their coding skills, as well as for companies seeking an efficient way to evaluate candidates' technical abilities during the hiring process.
Overall verdict
Why this product is good
Recommended for
Walkthroughs and reviews on video.
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing HackerRank and CalcSphere.
CalcSphere's answer:
Zakat Calculator with Pakistani Fatwa — The only free Zakat calculator following the silver nisab ruling of Mufti Taqi Usmani (Fiqhi Muqalat Vol 1, Page 31) and Darul Uloom Karachi. Silver nisab is pre-selected by default for mixed assets.
Multi-currency support with live rates — All finance calculators support PKR, USD, EUR, GBP, AED and 7 more currencies with live exchange rates from open.er-api.com
70+ calculators in one place — Finance, health, math, construction, unit converters and date tools all under one clean interface
Construction calculators for Pakistan — Concrete volume, bricks, paint, tiles, steel weight and construction cost per marla — built for Pakistani builders and engineers
100% free, no sign-up, no ads blocking the calculator — All calculations run locally in your browser. No data is stored or sent to any server.
Perfect PageSpeed scores — 100/100 Performance, 100/100 SEO, 100/100 Best Practices on Google PageSpeed Insights
CalcSphere's answer:
No clutter — Unlike calculator.net and rapidtables.com, CalcSphere puts the calculator first with no pop-ups, no distracting ads blocking the tool, and instant results
Mobile-first design — Built with Next.js 14 and Tailwind CSS, CalcSphere loads in under 1 second on mobile (LCP 1.3s) — faster than most competitor sites
Dark and light mode — Clean modern UI with full dark mode support unlike most legacy calculator sites
Dropdown inputs — No need to type unit abbreviations manually — all unit converters use dropdown selection
Rich explanations — Every calculator includes a "What is" section, step-by-step how-to guide, pro tips, and real-world use cases — not just a bare calculator
Pakistan-specific tools — Zakat calculator, construction cost per marla, PKR salary calculator and EMI calculator built for Pakistani users — not available on international competitors
CalcSphere's answer:
CalcSphere serves four main audiences:
Pakistani users — Professionals, students and homeowners calculating EMI, Zakat, construction costs, salaries and inflation in PKR
UK and international business users — Small business owners calculating business loan repayments, VAT, stamp duty and retirement planning
Students and academics — Math and science students using percentage, GPA, quadratic solver, square root and fraction calculators
Health and fitness enthusiasts — People tracking BMI, calorie deficit, body fat, ideal weight and running pace
CalcSphere is used in 80+ countries with strongest traffic from Pakistan, United Kingdom, United States, Australia, South Africa and Malaysia.
CalcSphere's answer:
CalcSphere was built out of frustration with existing calculator websites — most are cluttered with ads, slow to load, and don't serve non-US audiences well.
The goal was simple: build the fastest, cleanest, most accurate free calculator website that works for everyone — from a Pakistani homeowner calculating construction costs to a UK small business owner planning a loan.
The Zakat calculator was a particularly important addition. Most online Zakat calculators use incorrect nisab values or don't explain which scholarly standard they follow. CalcSphere's Zakat calculator is built on the verified fatwa of Mufti Taqi Usmani (Fiqhi Muqalat Vol 1, Page 31) and defaults to silver nisab for mixed assets — making it the most accurate free Zakat calculator available online.
Built with Next.js 14, Tailwind CSS and deployed on Vercel, CalcSphere launched in April 2026 and achieved 100/100 Google PageSpeed scores on both mobile and desktop.
CalcSphere's answer:
CalcSphere is a free tool used by individual users worldwide — not a B2B SaaS product with named customers
Users include students, homeowners, small business owners, construction contractors, financial planners and Muslim professionals calculating Zakat
Active users in 80+ countries including Pakistan, United Kingdom, United States, Australia, India, South Africa, Malaysia and Bangladesh
CalcSphere's answer:
Share your experience with using HackerRank and CalcSphere. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


What are LeetCode and LeetCode alternatives good for?LeetCode💡Interested in leveling up your career? Apply to the Formation Fellowship...
HackerRank’s challenges cover a wide range of topics and difficulty levels, allowing developers to enhance their problem-solving skills and learn new algorithms and data structures. The competitive nature of...
HackerRank offers a wide array of challenges across various domains such as algorithms, mathematics, SQL, and functional programming. Its interface is user-friendly, and the platform provides detailed feedback on...
We have no reviews of CalcSphere yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


This way, you transfer what you already know (problem-solving) but only change the syntax. Platforms like Hackerrank are also great to solve the same problem in different languages and learn from other people’s solutions. - Source: dev.to / about 1 year ago
Firstly, solve some common data structure problems with it. Implement some data structures like arrays, linked lists, stacks, queues, etc. You can check common problems on LeetCode, Hackerank or some other resources. - Source: dev.to / over 2 years ago
I don't have a consecutive internet connection and I can't keep up learning process so I started practicing in hackerrank.com I have started some challenges in python and c++ there. Thus I have no internet connection so I cannot practice... Source: almost 3 years ago
Tracking CalcSphere since Jun 2026.
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