Math & percentage calculators that just work
Free, privacy-first math and percentage calculators. Instant results, clear formulas, and step-by-step explanations. Everything runs in your browser — your numbers never leave your device.
- Instant ResultsNo loading, no waiting
- Always AccurateStandard formulas, verified
- 100% PrivateYour data never leaves your browser
- Completely FreeNo sign-up, no subscription
All calculators
Browse by category →Percentage Calculator
Work out any percentage instantly — three calculators in one.
Percentage Increase Calculator
Add a percentage to a number, or find the percent increase between two values.
Percentage Decrease Calculator
Subtract a percentage from a number, or find the percent decrease between two values.
Discount Calculator
See how much you save and what you pay after a percent-off discount.
Tip Calculator
Calculate the tip and split the total between any number of people.
Average Calculator
Find the mean, median, sum, min, max, and range of a list of numbers.
GPA Calculator
Calculate your grade point average on the 4.0 scale, weighted by credits.
Fraction to Decimal Converter
Convert any fraction to a decimal (and a percentage), with the simplified form.
Random Number Generator
Generate random numbers in any range — with optional unique values.
Margin Calculator
Find profit, profit margin, and markup from cost and revenue.
VAT Calculator
Add or remove VAT (or sales tax) to find the net, tax, and gross amounts.
Age Calculator
Calculate exact age in years, months, and days between two dates.
Percentage Difference Calculator
Find the percentage difference between two values, relative to their average.
Ratio Calculator
Simplify ratios and solve proportions (A : B = C : ?).
BMI Calculator
Calculate body mass index from height and weight (metric or imperial).
Sales Tax Calculator
Add sales tax to a price, or remove it from a total.
Hours Calculator
Find the hours and minutes between times — including overnight shifts.
Date Calculator
Days between two dates, or add and subtract days from a date.
Compound Interest Calculator
See how savings grow with compound interest and regular contributions.
TDEE Calculator
Estimate your daily calorie burn (TDEE) and BMR.
Standard Deviation Calculator
Find standard deviation, variance, and mean for a data set.
Commission Calculator
Calculate sales commission and total pay from a sale and rate.
Percent Error Calculator
Compare a measured value to the true value as a percentage.
Mortgage Calculator
Estimate your full monthly mortgage payment — PITI, PMI, and HOA.
Loan Calculator
Monthly payment, total interest, and payoff schedule for any loan.
Home Affordability Calculator
How much house can you afford? Based on the 28/36 DTI rule.
Amortization Schedule
A complete payment-by-payment breakdown for any loan.
Auto Loan Calculator
Estimate your car payment with trade-in and sales tax.
Credit Card Payoff Calculator
See how fast you'll be debt-free — and the cost of paying only the minimum.
Savings Goal Calculator
Find the monthly amount to save to hit your target on time.
Unit Converter
Convert between length, weight, temperature, area, volume, speed, time, and data units instantly.
Scientific Calculator
A full scientific calculator — trig, logs, powers, factorials, and constants.
Date Difference Calculator
Days, weeks, months, and working days between two dates.
Time Zone Converter
Convert times between any two cities, with a live world clock.
Password Generator
Strong, random passwords generated entirely in your browser.
Grade Calculator
Weighted grade average, letter grade, GPA — and the score you need on the final.
Pace Calculator
Running pace, finish time, and speed — with per-distance splits.
Frequently asked questions
Are all calculations done in my browser?
Yes. Every calculation on Numvella runs entirely in your browser using JavaScript — your numbers are never sent to a server, stored, or shared.
Is Numvella free to use?
Completely free — no sign-up, no subscription, no hidden fees. All 37 calculators are free to use as often as you like.
How accurate are the results?
Numvella uses standard mathematical formulas and IEEE 754 double-precision floating-point arithmetic, with results rounded for display. Every formula is unit-tested against known edge cases.
Can I share a calculation with someone?
Yes. Every calculator generates a unique shareable URL that encodes your inputs, so anyone who opens the link sees the same calculation — the values live only in the link you share.
What calculators does Numvella offer?
Numvella currently offers 37 calculators across six categories: percentages, finance, math, everyday, health, and time — from percentage and tip to BMI, TDEE, compound interest, and standard deviation.
Does Numvella work offline?
Yes. Once the page has loaded, all calculators work without an internet connection, since every calculation happens locally in your browser.