Buying a home
From "can I afford this" to "what does closing day actually cost" — every number you'll want before signing.
Numora is a friendly library of free online calculators — built by engineers, editors, and domain reviewers who care about accuracy. Every formula is peer-reviewed against a primary source. Every calculation runs in your browser. Your data never leaves your device.
12 subjects
Pick your subject.
12 big buckets, 36 tools inside. Tap any card to dive in.
Trending this week
Most-loved calculators.
Refreshed weekly from usage. No paid placements — popularity is the only signal.
Editor's picks
A closer look at our biggest sections.
Money stuff.
Loans, taxes, retirement — the calculators that show up in every big financial decision.
Explore finance tools · 9 totalYour body.
Calorie math, body composition, fitness targets — reviewed against WHO and CDC guidance.
Explore health tools · 7 totalMath homework.
Student-grade to professional-grade tools with every step shown.
Explore math tools · 5 total By life situation
What are you trying to figure out?
Calculators grouped by the problem you're solving — not by math subject.
Tracking fitness
Body composition and energy needs benchmarks so you can plan real changes, not guesses.
School & study
Grades, homework percentages, geometry that actually shows up on tests.
Managing money
The tools you'll use when taxes are due, savings goals need sizing, or a deal looks too good.
Home projects
Size the job yourself — paint coverage, length and temperature conversions, honest quotes.
Daily small stuff
Tips, mileage, time-between-dates — the stuff you'd have reached for a calculator app for.
Why use Numora
36+
Calculators, cited.
Every formula ties to a primary source — CFPB, WHO, IRS, Freddie Mac, IUPAC. No black boxes.
0¢
Always free.
No sign-up, no paywalls, no feature gates. Calculators are free forever; ads live only on content.
100%
Private by design.
The math runs in your browser. The values you type never reach our servers.
Are these calculators free?
Yes. Every calculator is free with no sign-up, no paywalls, and no result limits. Modest display advertising lives only on content below the calculator itself.
How accurate are results?
Every formula is reviewed by a domain editor against a primary source (CFPB, WHO, IRS, IUPAC, Freddie Mac, etc.) and re-verified annually. Sources are cited on every calculator.
Can I embed a calculator?
Embeds are on the roadmap. If you'd like early access for a publication or educator portal, email us — we'll prioritize the most-requested tools.
Do you store my data?
No. Every calculation runs in your browser. The numbers you type never leave your device. Aggregate analytics (page views, country) can't identify an individual visitor.
What subjects do you cover?
Math, finance, health, physics, chemistry, engineering, construction, automotive, computing, statistics, unit conversion, and everyday life — 12 categories in total.
Who builds the calculators?
Subject-matter editors and reviewers with domain credentials. YMYL calculators (money, health, tax) carry a visible reviewer byline.
About Numora
Calculators, built the right way.
We build the calculator library we always wanted — a single trustworthy place for quantitative questions that explains the number as well as computes it. Formulas are traced to a primary source, YMYL calculators carry a reviewer byline, and every assumption the engine makes is listed on the page.