Best Free Online Calculators for Everyday Use: Percentage, Calorie, Loan, Fees & More

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Introduction

Whether you’re managing your budget, planning a diet, running a business, or just need a quick answer for homework, calculators make everyday math simple and accurate.
But with so many online options, it’s hard to know which are truly reliable—and which will waste your time.
That’s why SEOfig brings you a complete suite of free, fast, and easy-to-use online calculators to handle everything from sales tax and margin calculations to calorie counting, loan planning, and fee deduction.

In this guide, you’ll discover the best calculators for every area of life, see exactly how to use each one, and learn from real-world scenarios—so you can make smarter, faster decisions every day.

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Why Use Online Calculators?

• Accuracy: Instant, mistake-free answers (no more calculator typos or spreadsheet errors)

• Convenience: No downloads, logins, or math skills required—use from any device, anytime

• Breadth: All the calculators you need, in one place (finance, health, time, math, fees, and more)

• Privacy: No data is stored or shared; you’re always in control

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Finance & Business Calculators

Sales Tax Calculator

What It Does & Who Needs It

Automatically calculates sales tax for any amount, making it a must-have for shoppers, small business owners, freelancers, and anyone selling products or services.

How to Use

1. Enter the purchase or invoice amount.

2. Input your sales tax rate (local or state, as needed).

3. Instantly see the total with tax, the tax amount alone, and the amount before tax.

Case Uses

• Online shopping: Know your final total before checkout.

• Small business invoices: Add the right tax to bills for customers.

• Freelancers: Calculate sales tax for services rendered in different locations.

Example

Emily is selling handmade candles online. She uses the Sales Tax Calculator to add the correct rate for each customer’s state, ensuring her invoices are always accurate and compliant.

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Margin Calculator

What It Does & Who Needs It

Calculates your profit margin—how much you actually earn after expenses. This tool is vital for shop owners, resellers, and anyone setting prices.

How to Use

1. Enter your cost price and selling price.

2. Instantly get the profit amount and percentage margin.

Case Uses

• E-commerce sellers: Set competitive prices while guaranteeing profit.

• Freelancers: Quote projects, knowing your true profit.

• Local stores: Evaluate which products are most profitable.

Example

Alex runs a Shopify store. With the Margin Calculator, he checks each product’s margin to make sure it’s worth listing—helping him double his profits last year.

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Discount Calculator

What It Does & Who Needs It

Quickly finds the final price after a percentage discount—great for shoppers, business owners, and anyone running sales or promotions.

How to Use

1. Enter the original price and discount percentage.

2. See the savings, final price, and how much you’ll pay or receive.

Case Uses

• Shoppers: Plan purchases during Black Friday or store sales.

• Retailers: Advertise promotions confidently.

• Event organizers: Offer group rates and see exact savings.

Example

Jasmine wants to buy a $120 jacket with a 35% sale. The Discount Calculator shows she’ll pay $78, making the decision easy.

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CPM Calculator

What It Does & Who Needs It

Calculates Cost Per Mille (CPM), or cost per 1,000 impressions—vital for digital marketers, advertisers, and business owners.

How to Use

1. Input the total ad spend and number of impressions.

2. Get the CPM instantly.

Case Uses

• Ad campaign planning: Compare platforms by CPM rates.

• Content creators: Estimate potential ad income.

• Agencies: Prove campaign value to clients.

Example

A marketing agency spends $2,000 on a campaign with 500,000 impressions. The CPM Calculator shows a $4 CPM, making it easy to compare performance across ads.

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Loan Calculator

What It Does & Who Needs It

Estimates monthly payments, total interest, and payoff time for any loan. Essential for students, home buyers, car shoppers, and anyone considering financing.

How to Use

1. Enter the loan amount, interest rate, and repayment term.

2. See the monthly payment and total cost at a glance.

Case Uses

• Car loans: Budget monthly costs before shopping.

• Student loans: Plan for life after graduation.

• Small business loans: Assess financing for growth or equipment.

Example

Miguel is thinking of buying a $15,000 used car. With the Loan Calculator, he knows a 48-month, 6% loan means payments of about $352/month—helping him negotiate with confidence.

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GST Calculator

What It Does & Who Needs It

Calculates Goods and Services Tax (GST) for goods and services—used by business owners, accountants, and freelancers in regions where GST applies.

How to Use

1. Input the price before or after GST.

2. Select your GST rate.

3. Instantly see GST amount and net price.

Case Uses

• International freelancers: Prepare invoices for clients abroad.

• Retail businesses: Separate GST for accounting.

• Service providers: Ensure compliance in GST regions.

Example

Priya, a freelance designer in India, uses the GST Calculator to quickly add the correct GST to every invoice, avoiding headaches at tax time.

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Health & Fitness Calculators

Calorie Calculator

What It Does & Who Needs It

Estimates your daily calorie needs for weight loss, gain, or maintenance—perfect for anyone on a health journey, athletes, or nutrition planners.

How to Use

1. Enter your age, gender, height, weight, and activity level.

2. Instantly see how many calories you need per day.

Case Uses

• Weight loss: Set calorie goals to lose weight safely.

• Athletes: Ensure proper fueling for performance.

• Meal planners: Create balanced menus for families or clients.

Example

Mike wants to lose 10 pounds. He learns his daily maintenance is 2,400 calories, so he targets 1,900/day for steady, healthy weight loss.

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TDEE Calculator

What It Does & Who Needs It

Calculates Total Daily Energy Expenditure (TDEE)—a precise measure of how many calories you burn each day, factoring in exercise and activity.

How to Use

1. Enter personal data (like in the Calorie Calculator).

2. Add details about daily exercise.

3. Instantly see your true TDEE.

Case Uses

• Bodybuilders: Fine-tune calories for “bulking” or “cutting.”

• Fitness coaches: Personalize plans for clients.

• Dieters: Avoid “undereating” by understanding actual calorie needs.

Example

Lisa wants to gain muscle but not fat. The TDEE Calculator shows her the exact calorie surplus she needs for lean growth.

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Time & Date Calculators

Age Calculator

What It Does & Who Needs It

Quickly finds a person’s exact age in years, months, and days. Useful for HR, education, sports, or just curiosity.

How to Use

1. Enter the date of birth (and optional “as of” date).

2. Instantly see the exact age.

Case Uses

• School registration: Verify student ages for grade placement.

• Sports teams: Confirm eligibility for leagues.

• Government or HR: Calculate retirement or benefit eligibility.

Example

A school registrar needs to confirm if a child is old enough for kindergarten. The Age Calculator provides the answer in seconds.

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Days Calculator

What It Does & Who Needs It

Calculates the number of days between two dates—a must for project planners, HR, students, and event organizers.

How to Use

1. Enter start and end dates.

2. Instantly get the total days (plus weeks or months, if needed).

Case Uses

• Project managers: Plan deadlines or delivery dates.

• Students: Count days to exams or assignment due dates.

• Vacation planners: Know how many days until your trip!

Example

A project manager calculates there are 42 days between project kickoff and deadline—perfect for setting milestones.

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Hours Calculator & Month Calculator

What They Do & Who Needs Them

• Hours Calculator: Add or subtract hours (and minutes), ideal for work logs, schedules, or event planning.

• Month Calculator: Find the number of months between two dates for budgeting, contracts, or plans.

How to Use

• For hours, enter start and end times, or total hours to sum up.

• For months, enter two dates; get months instantly.

Case Uses

• Employees: Track total hours worked for payroll.

• Renters: Calculate lease or contract periods.

• Event planners: Schedule events and see monthly progress.

Example

Sara works 8:30 am to 5:15 pm every weekday. The Hours Calculator totals her weekly hours for easy payroll submission.

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General Math/Stats Calculators

Percentage Calculator

What It Does & Who Needs It

Calculates any percentage math instantly—crucial for students, shoppers, businesses, and anyone working with numbers.

How to Use

1. Enter the base number and percentage.

2. See the result instantly.

Case Uses

• Homework: Solve math problems or check work.

• Shopping: Calculate discounts, tax, or tips.

• Business: Analyze growth or financial data.

Example

A student double-checks their math homework: What is 15% of 320? The calculator says 48—homework done in seconds.

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Average Calculator

What It Does & Who Needs It

Finds the mean of any set of numbers. Perfect for schoolwork, sports, budgeting, and business analysis.

How to Use

1. Enter your numbers, separated by commas.

2. Instantly see the average.

Case Uses

• Teachers: Grade assignments or tests quickly.

• Sports coaches: Track player or team stats.

• Small business: Calculate average sales, expenses, or reviews.

Example

A basketball coach enters players’ scores from a season to find the team’s average points per game.

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Confidence Interval Calculator

What It Does & Who Needs It

Computes the confidence interval for sample data used in statistics, research, surveys, and academics.

How to Use

1. Enter the mean, sample size, and standard deviation.

2. Select confidence level (e.g., 95%).

3. Instantly get the interval range.

Case Uses

• Researchers: Analyze survey results.

• Students: Complete statistics homework.

• Businesses: Forecast trends with data certainty.

Example

A pollster wants to know the margin of error for a 500-person survey. The Confidence Interval Calculator shows a range of ±4.4%.

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Probability Calculator

What It Does & Who Needs It

Solves basic probability problems—helpful for students, educators, and those studying statistics.

How to Use

1. Enter the number of possible outcomes and the number of favorable outcomes.

2. Instantly get the probability as a decimal, fraction, or percentage.

Case Uses

• Classroom learning: Practice probability concepts.

• Gamers: Calculate odds of winning.

• Researchers: Analyze statistical chances.

Example

A student calculates the probability of drawing an ace from a deck of cards: The Probability Calculator says 1 in 13.

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Advanced Use Cases & Workflow Examples

• Side Hustle Success:
  Ravi runs a side business reselling sneakers. He uses the Margin Calculator for pricing his products and the Days Calculator to track shipping estimates and delivery times all in one streamlined workflow.

• Fitness Transformation:
  Jamie uses the Calorie Calculator to set daily targets, the TDEE Calculator for weekly adjustments, and the Month Calculator to plan progress checks.

• Freelancer’s Toolkit:
  Emma calculates discounts for early payment, invoices with the Sales Tax Calculator, logs her project hours, and checks net income after Stripe fees.

• Student Efficiency:
  Maya completes her math homework using the Percentage Calculator, verifies her research sample’s confidence interval, and tracks assignment deadlines with the Days Calculator.

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Why Use SEOfig for Calculators?

• Completely Free: All tools are open access. This means no logins, paywalls, or hidden fees.

• No Downloads or Spam: Use directly in your browser, on desktop or mobile.

• Secure & Private: Your data isn’t stored or shared.

• All-in-One Access: Everything you need, in one place with easy navigation and no popups.

• Always Accurate: Regular updates, with results you can trust.

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FAQs

Are these calculators really free?
Yes!every tool on SEOfig is 100% free to use.

Can I use them for business, official, or legal purposes?
Absolutely. They’re designed for accuracy and practical use.

Do the calculators work on mobile devices?
Yes! SEOfig tools are optimized for any device.

How accurate are the results?
Our tools use industry-standard formulas and are regularly checked for accuracy.

What if I don’t see the calculator I need?
Let us know! SEOfig is always adding new calculators based on user requests!

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Conclusion & Call to Action

No more math headaches or complicated spreadsheets.
With SEOfig’s suite of free online calculators, you have every tool you need for business, health, school, and daily life.
Whether you’re setting prices, counting calories, managing projects, or solving math problems, you’ll get fast, accurate answers every time.

Ready to make smarter decisions?
Try SEOfig’s free online calculators now—and bookmark the site for all your future needs.

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TL;DR Summary

• Instantly calculate percentages, margins, sales tax, calories, fees, loans, dates, and more

• Free, accurate, private, and easy to use—anytime, anywhere

• Upgrade your workflow with SEOfig’s complete calculator suite

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