Free Online Calculators - Percentage, Loan, GST, Sales Tax & More | SeoStackTools
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Free Online Calculators
From working out a discount at checkout to calculating a loan's monthly payment or your daily calorie needs, these free calculators handle the math instantly in your browser. No downloads, no signup, no ads blocking the result — just enter your numbers and get an accurate answer.
Financial & Business Calculators
Whether you're pricing a product, filing taxes, or estimating a loan, these tools cover the everyday business math. Use the Sales Tax Calculator and GST Calculator to add or extract tax from a price, the Discount Calculator to work out sale prices, the Margin Calculator to price products profitably, the Loan Calculator for monthly payments and interest, and the CPM Calculator to work out ad campaign cost-per-thousand-impressions.
Math & Statistics Calculators
Quick tools for everyday and academic math. The Percentage Calculator handles percentage increases, decreases, and of-a-number problems, the Average Calculator finds the mean of a data set, the Probability Calculator works out event probabilities, and the Confidence Interval Calculator is built for statistics coursework and research reporting.
Date, Time & Health Calculators
Need to know how many days until a deadline, or your daily calorie target? Use the Days Calculator, Hours Calculator, and Month Calculator for date and duration math, and the Calorie Calculator and TDEE Calculator to estimate daily energy needs based on your body stats and activity level.
How to Use These Calculators
- Pick the calculator that matches what you're solving for — financial, math, or date/health.
- Enter your known values into the input fields (e.g. price and tax rate, or start and end dates).
- Click Calculate to get an instant result — most tools also show the formula used, so you can verify or learn the method.
- For financial calculators, double check the specific rate (tax %, interest rate) for your region or lender, since rates vary widely.
Frequently Asked Questions
Are these calculators accurate for tax filing or financial decisions?
They use standard formulas and are accurate for the inputs given, but for official tax filing or major financial decisions (like signing a loan), always verify with your accountant, bank, or local tax authority since regional rules and rounding conventions can vary.
What's the difference between markup and margin?
Markup is the percentage added to your cost to set the price; margin is the percentage of the final price that is profit. Use the Margin Calculator to see both figures from the same inputs.
How is TDEE different from calorie needs?
TDEE (Total Daily Energy Expenditure) is the total calories you burn in a day including activity, while a basic calorie calculator often only estimates your resting/basal rate. Use the TDEE Calculator for a more complete picture if you're active.
Can I calculate the number of days between two dates including or excluding the end date?
The Days Calculator shows the full day count between two dates — check the result against your specific need (inclusive or exclusive) since conventions differ by use case (e.g. contracts vs. billing cycles).
Are these tools free with no usage limits?
Yes, all calculators on this page are free to use with no signup and no daily limits.
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