What can we calculate for you today?
Hundreds of free, expertly built calculators and online tools for finance, health, math, everyday life, Christmas, Islamic, Hindu, text, images, PDFs, developers and more — all running in your browser with no tracking.
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Calculators on the left for every life decision; on the right, online tools for text, images, PDFs, developers and design.
Featured calculators
The most-used calculators on CalcaTools — useful, fast, and accurate.
Hypothekenrechner | Monatliche Hypothekenraten berechnen
Estimate monthly mortgage payments with taxes and insurance.
BMI-Rechner | BMI berechnen und Gewichtsklasse ermitteln
Check your Body Mass Index and healthy weight range.
Kreditrechner | Monatliche Rate und Gesamtzinsen berechnen
Calculate loan payments, interest and full amortization.
Prozentrechner | Berechnung von X % von Y und prozentuale Veränderung
Calculate percentages, increases, decreases and ratios.
Zinseszinsrechner | Berechnung des Sparwachstums im Zeitverlauf
See how your investments grow with compound interest.
Altersrechner | Das genaue Alter zwischen zwei Daten ermitteln
Calculate exact age in years, months, days and seconds.
Zakat-Rechner | Berechnen Sie 2,5 % Zakat mit Aufschlüsselung des Vermögens
Compute your annual Zakat with the latest Nisab value.
Kundali-Rechner | Kundali anhand der Geburtsdaten berechnen
Generate a Vedic Janma Kundali with Lahiri Ayanamsa.
Featured tools
The most-used online tools on CalcaTools — text utilities, image work, PDFs, code helpers and generators.
Wortzähler | Wörter, Zeichen, Sätze und Lesezeit zählen
Real-time word, character and reading-time counter for any text.
Passwortgenerator | Starke, zufällige Passwörter lokal erstellen
Build strong random passwords with length and symbol controls.
QR-Code-Generator | QR-Codes für URLs, Text und WLAN erstellen
Generate downloadable QR codes for URLs, vCards, Wi-Fi and more.
PDF-Komprimierer | PDF-Dateigröße lokal ohne Qualitätsverlust reduzieren
Shrink PDF file size in your browser — no upload needed.
JSON-Formatter | JSON lokal formatieren, validieren und minimieren
Format, validate and minify JSON with syntax highlighting.
Farbauswahl | Farben auswählen und HEX-, RGB-, HSL- und CSS-Werte kopieren
Pick colors and copy HEX / RGB / HSL / OKLCH values.
Temperaturumrechner | Umrechnung von Celsius, Fahrenheit und Kelvin
Convert temperatures between Celsius, Fahrenheit and Kelvin.
Bildkompressor | Dateigröße von JPG-, PNG- und WebP-Dateien lokal reduzieren
Compress JPG / PNG images client-side to save bandwidth.
Expert Guides & Insights
Detailed tutorials, calculator breakdowns, and expert explanations of our formulas.
Kiesrechner: Tonnage und Kubikyard ganz einfach berechnen
I remember standing in my driveway a few years ago, staring at a pile of gravel that looked like a small mountain. I had ordered twelve tons of crushed stone because I “eyeballed” the measurements. By the time I finished spreading it, I had a two-foot-high surplus sitting on my lawn. It killed the grass, […]
Körpertyp-Rechner: Leitfaden zur Ermittlung von Größe und Gewicht
Ich erinnere mich, wie ich vor drei Jahren vor einem Spiegel in der Umkleidekabine stand und eine „Slim-Fit“-Chino-Hose in der Hand hielt, die sich einfach nicht über meine Oberschenkel ziehen ließ. Laut Größentabelle hätte sie mir aufgrund meiner Größe und meines Gewichts perfekt passen müssen. Ich war nicht übergewichtig. Ich war einfach anders gebaut als […]
Rechner für Landschaftsbausteine: Schätzen Sie den Bedarf für Ihr Projekt
I remember the first time I tried to “eyeball” a gravel delivery for my side yard. I figured three truckloads would be plenty. When the driver dumped the piles, I realized I had enough stone to pave my driveway twice over, but barely enough to cover the actual muddy path I was trying to fix. […]
So berechnen Sie Ihr genaues Alter in Jahren, Monaten und Tagen (manuelle Methode + Beispiele)
Ever tried to figure out exactly how old you are for a legal form or a milestone celebration? Just subtracting years isn’t enough. If you want the precise breakdown of years, months, and days, you need a specific math technique called the borrowing method. It is the same logic used by computer software, but you […]
Live market prices
Track crypto, stocks, indices, commodities and forex in one clean live board — auto-updating, free, no signup.
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Prices are indicative, may be delayed up to ~15 minutes, and are for information only — not financial advice. Crypto data by CoinGecko; equities/indices by Yahoo Finance.
Why use CalcaTools
Trusted by thousands of users for everyday calculations — built by people who actually use the tools.
Expert-reviewed formulas
Health, finance, religious and astronomical formulas are reviewed by a named in-house panel and re-checked every quarter.
100% private, in-browser
Every calculation runs client-side. Your inputs never leave your device — no accounts, no logs, no third-party sharing.
Fast and responsive
Compiled CSS, lazy fonts, no Tailwind CDN — every page loads in under a second on a 4G phone connection.
Cited sources, full methodology
Each tool documents the exact formula and links to an authoritative source — CFPB, WHO, NIST, ISKCON, Hilal Committee, and more.