OmniCalculator，免费在线计算器
Free Online Calculators
9 个计算器：简单、科学、百分比、BMI、体脂、卡路里、年龄、日期和预产期。
选择一个计算器开始
What is OmniCalculator?
OmniCalculator is the calculator suite of OmniConverter, nine free browser-based calculators for everyday life: simple & scientific math, percentages, BMI, body fat, calories, age, dates, and pregnancy due date. Every calculation follows the same formulas as calculator.net — trusted formulas, instant results, no uploads, and 100% private.
All tools run client-side. Your health, date, and history inputs never leave your device. Use on desktop or mobile, light or dark, no sign-up required.
Learn: Calculator Guides
Every Calculator, Explained
Simple & Scientific
Four-function with memory, percent and sqrt, plus trig, logs, powers, and factorial in DEG/RAD — just like a handheld TI.
Percentage
What is X% of Y, X is what % of Y, X is Y% of what, plus increase/decrease — the three classic forms.
BMI & Body Fat
BMI with WHO categories and healthy range, body fat via U.S. Navy (tape) and BMI method with charts.
Calorie
BMR via Mifflin-St Jeor & Harris-Benedict, TDEE by activity, plus deficit/surplus for goals.
Age & Date
Exact age in Y/M/D with totals, next birthday, and date difference / add-subtract with weekday & business-day logic.
Due Date
Naegele's rule from LMP or conception (+280/266 days), cycle correction, gestational age, trimester milestones.
Why OmniCalculator?
Accurate by design. Formulas verified against calculator.net and authoritative sources (U.S. Navy, WHO, Mifflin-St Jeor). Units never leave your browser.
9 Calculators
Math, health, and date — one suite, no tab-hopping.
8 Languages
Every calculator in English, Spanish, French, German, Chinese, Japanese, Hindi, and Arabic.
100% Private
Client-side only, no server storage, no data retention.