Unit Converter
ブラウザ内で処理長さ・重さ・温度・面積・体積の単位変換ツール。リアルタイム変換対応。
How to Use the Unit Converter
This unit converter tool supports five categories of measurements: Length, Weight, Temperature, Area, and Volume. Select a category using the tabs at the top, enter a value, choose the source and target units from the dropdown menus, and the conversion result appears instantly. Use the swap button to quickly reverse the conversion direction. All calculations are performed in your browser with no data sent to any server.
Supported Unit Categories
Length conversions cover metric units (mm, cm, m, km) and imperial units (inch, foot, yard, mile). Weight supports milligrams through metric tons plus ounces and pounds. Temperature converts between Celsius, Fahrenheit, and Kelvin. Area handles square millimeters through square kilometers, plus square inches, square feet, acres, and hectares. Volume includes milliliters, liters, and US customary units like gallons, cups, fluid ounces, pints, and quarts.
Conversion Accuracy
All conversions use precise conversion factors based on international standards. The tool displays results with up to 10 significant digits for normal values, and uses scientific notation for very small numbers. Temperature conversions correctly handle the offset between scales, not just multiplication factors. The real-time calculation updates as you type, making it easy to explore different values and compare results across unit pairs without manually clicking a convert button.
単位変換ツールの使い方
長さ・重さ・温度・面積・容量の5カテゴリをタブで切り替え、数値を入力して変換元・変換先の単位を選ぶだけです。 入れ替えボタンで変換方向を即座に反転できます。海外レシピの換算、輸入品のサイズ確認、 技術文書のヤード・ポンド法→メートル法変換などにご利用ください。
温度・単位系の変換でよくある誤り / Common Mistakes Converting Temperature and Imperial Units
| 落とし穴 / Pitfall | 問題 / Problem | 対処 / Fix |
|---|---|---|
| 温度の「差」を同じ式で換算 Converting temperature differences with the absolute formula | 「5°C上がった」は9°F上昇であって41°Fではない。差分にはオフセット(+32)を適用しない A +5°C change is +9°F; the +32 offset only applies to absolute temps | 絶対温度は F=C×9/5+32、温度差は ΔF=ΔC×9/5 Use ×9/5 only for deltas, full formula for absolutes |
| 液量オンスの US / UK 混同 US vs UK fluid ounces | US fl oz = 29.57mL、UK(Imperial)= 28.41mL。ガロンも US 3.785L / UK 4.546L と別物 US and Imperial gallons/ounces differ by up to 20% | レシピや仕様書の出典国を確認(本ツールはUS基準) Check the source country; this tool uses US units |
| 坪・畳の地域差 Japanese tsubo/tatami variations | 1坪≈3.306m2だが、畳は江戸間・京間などで面積が異なる Tatami sizes vary by region | 不動産では「1坪=3.30578m2」の公式換算を使う Use the official 3.30578 m2 per tsubo |
| 重量トンの種類 Metric ton vs short/long ton | メートルトン1,000kg・米トン907kg・英トン1,016kgが混在 1,000 kg vs 907 kg vs 1,016 kg | 国際取引では「t(メートルトン)」を明示(本ツールはメートルトン) Specify metric tons explicitly |
| 浮動小数点の見かけ誤差 Floating-point display artifacts | 0.1単位の換算で 0.30000000000000004 のような表示が出ることがある Binary floats can show tiny artifacts | 有効桁数で丸めて利用(本ツールは10桁で丸め済み) Round to significant digits (this tool already does) |
換算式の例 / Formulas
温度: F = C × 9/5 + 32 K = C + 273.15
長さ: 1 inch = 2.54 cm (定義値) 1 mile = 1.609344 km
重さ: 1 lb = 453.59237 g (定義値) 1 oz = 28.3495 g
面積: 1 acre ≈ 4046.86 m2 1 ha = 10000 m2
容量: 1 US gal = 3.785412 L 1 US cup = 236.588 mL距離・温度・重さの換算例 / Sample Conversions: Distance, Temperature, Weight
5 km → 3.107 mile (ランニング距離)
350 °F → 176.7 °C (オーブンレシピ)
2 lb → 907.2 g (食材)
1500 sq ft → 139.35 m2 (海外物件の面積)同梱の換算係数でオフライン単位変換 / Offline unit conversion with bundled factors
Unit conversion needs no server — the math is deterministic and the conversion factors are public standards. This tool ships all factors with the page and computes everything locally: no tracking of what you convert, no latency, and full offline support once loaded. Your measurements (which can reveal projects, recipes, or shipments you are working on) stay on your device.
換算係数は全てページに同梱されており、計算はブラウザ内で完結します。 入力した数値が外部に送信されることはなく、オフラインでも動作します。
🔒 すべての処理はブラウザ内で完結し、入力データはサーバーへ送信されません。登録不要・無料。 / All processing runs in your browser; nothing is uploaded. Free, no sign-up. プライバシーポリシー / Privacy Policy