NISTデジタル数学関数ライブラリ（DLMF）
The NIST Digital Library of Mathematical Functions (DLMF) serves as the authoritative, peer-reviewed successor to the Abramowitz and Stegun Handbook
計算
プラスチック成形・射出成形価格計算ツール
Great for rapid estimations of the cost of your next plastic injected part. It has a nice database of plastic
GeoGebra科学計算機
Basic but does it well, with history, fractions and all features you want from a scientific calculator: GeoGebra Scientific is
無料のFEMをインストールまたはオンラインで使用できます
FEM software. Install is normally required (Mac, Windows, Linux) … but an online version is available (look at the right
Framacalc オンライン共同スプレッドシート
Not the most feature-rich spreadsheet, but ZERO install or registration: Framacalc is a collaborative, web-based spreadsheet service hosted by Framasoft
MH-Audio サウンドおよびオーディオ計算ツール（アーカイブ）
A very good resource for online Audio Calculators, classified into 6 categories: Loudspeaker Crossover Acoustic Electronic Turntable Various that really
オンライン整数列百科事典（OEIS）
The largest online integer sequences database, searchable. It provides a searchable interface to identify sequences by numerical terms, keywords, or
オンライン単位変換ツール
Efficient and well organised (be sure to look at the “by Family” drop-down and not stay at the “Most Popular”
Wolfram Alpha Science Reference & 計算科学
Provides engineering information and problem solving techniques and maths, all powered by a powerful search engine: WolframAlpha functions as a
統計表
Provides all the statistical tables when MS Excel has no formula to compute it automatically. All these tables here are