diff --git a/newtab.html b/newtab.html
index 93ff1a5..ae73e13 100644
--- a/newtab.html
+++ b/newtab.html
@@ -507,6 +507,7 @@
   <script src="src/js/widgets.js"></script>
   <script src="src/js/notes.js"></script>
   <script src="src/js/calculator.js"></script>
+  <script src="src/js/calc-scientific.js"></script>
   <script src="src/js/timer.js"></script>
   <script src="src/js/image-ref.js"></script>
   <script src="src/js/bookmark-import.js"></script>
diff --git a/src/css/main.css b/src/css/main.css
index 6a196bd..e622a4f 100644
--- a/src/css/main.css
+++ b/src/css/main.css
@@ -1332,6 +1332,65 @@ body.show-desc .bm-desc { display: block; }
   overflow-x: hidden;
 }
 
+/* Calculator Scientific Mode */
+.calc-sci-buttons {
+  grid-template-columns: repeat(3, 1fr);
+  margin-bottom: 4px;
+}
+.calc-formula-helper {
+  border-top: 1px solid var(--border);
+  padding-top: 8px;
+  margin-top: 4px;
+}
+.calc-formula-label {
+  font-size: 9px;
+  color: var(--text-muted);
+  text-transform: uppercase;
+  letter-spacing: 1px;
+  margin-bottom: 4px;
+}
+.calc-formula-select {
+  width: 100%;
+  padding: 4px 6px;
+  background: rgba(0,0,0,0.3);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  color: var(--text-primary);
+  font-size: 12px;
+  font-family: 'Rajdhani', sans-serif;
+  margin-bottom: 6px;
+}
+.calc-formula-row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  margin-bottom: 4px;
+}
+.calc-formula-row label {
+  font-size: 11px;
+  color: var(--text-secondary);
+  min-width: 50px;
+}
+.calc-formula-input {
+  flex: 1;
+  padding: 4px 6px;
+  background: rgba(0,0,0,0.3);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  color: var(--text-primary);
+  font-size: 12px;
+  font-family: 'Rajdhani', sans-serif;
+}
+.calc-formula-result {
+  font-size: 14px;
+  color: var(--accent);
+  font-weight: 600;
+  font-family: 'Rajdhani', monospace;
+  text-align: right;
+  min-height: 20px;
+  padding: 2px 0;
+}
+
 /* ============================================
    TIMER WIDGET
    ============================================ */
diff --git a/src/js/calc-scientific.js b/src/js/calc-scientific.js
new file mode 100644
index 0000000..ba3824b
--- /dev/null
+++ b/src/js/calc-scientific.js
@@ -0,0 +1,284 @@
+/* =============================================
+   HELLION NEWTAB — calc-scientific.js
+   Scientific-Modus für Calculator Widget
+   ============================================= */
+
+(function() {
+  'use strict';
+
+  const FORMULAS = [
+    {
+      key: 'circle_area',
+      fields: [{ key: 'radius', default: '' }],
+      calc: (vals) => Math.PI * vals.radius * vals.radius
+    },
+    {
+      key: 'circle_circumference',
+      fields: [{ key: 'radius', default: '' }],
+      calc: (vals) => 2 * Math.PI * vals.radius
+    },
+    {
+      key: 'celsius_to_fahrenheit',
+      fields: [{ key: 'temp', default: '' }],
+      calc: (vals) => (vals.temp * 9 / 5) + 32
+    },
+    {
+      key: 'fahrenheit_to_celsius',
+      fields: [{ key: 'temp', default: '' }],
+      calc: (vals) => (vals.temp - 32) * 5 / 9
+    },
+    {
+      key: 'pythagoras',
+      fields: [{ key: 'a', default: '' }, { key: 'b', default: '' }],
+      calc: (vals) => Math.sqrt(vals.a * vals.a + vals.b * vals.b)
+    },
+    {
+      key: 'percentage',
+      fields: [{ key: 'value', default: '' }, { key: 'percent', default: '' }],
+      calc: (vals) => vals.value * vals.percent / 100
+    }
+  ];
+
+  let _keyboardExtHandler = null;
+
+  function renderSciButtons(container) {
+    const grid = document.createElement('div');
+    grid.className = 'calc-buttons calc-sci-buttons';
+
+    const buttons = [
+      ['√',  'sqrt',   'operator'],
+      ['x²', 'square', 'operator'],
+      ['xⁿ', 'power',  'operator'],
+      ['π',  'pi',     'operator'],
+      ['e',  'euler',  'operator'],
+      ['±',  'negate', 'operator']
+    ];
+
+    buttons.forEach(([label, value, cls]) => {
+      const btn = document.createElement('button');
+      btn.className = 'calc-btn' + (cls ? ' ' + cls : '');
+      btn.textContent = label;
+      btn.type = 'button';
+      btn.addEventListener('click', () => handleSciKey(value));
+      grid.appendChild(btn);
+    });
+
+    container.appendChild(grid);
+  }
+
+  function handleSciKey(key) {
+    switch (key) {
+      case 'sqrt':
+        Calculator._currentExpr += 'sqrt(';
+        Calculator._updateDisplay();
+        break;
+      case 'square':
+        Calculator._currentExpr += '^2';
+        Calculator._updateDisplay();
+        break;
+      case 'power':
+        Calculator._handleKey('^');
+        break;
+      case 'pi':
+        Calculator._currentExpr += '3.14159265359';
+        Calculator._updateDisplay();
+        break;
+      case 'euler':
+        Calculator._currentExpr += '2.71828182846';
+        Calculator._updateDisplay();
+        break;
+      case 'negate':
+        handleNegate();
+        break;
+    }
+  }
+
+  function handleNegate() {
+    const expr = Calculator._currentExpr;
+    if (!expr && Calculator._lastResult) {
+      const num = parseFloat(Calculator._lastResult);
+      if (!isNaN(num)) {
+        Calculator._currentExpr = String(-num);
+        Calculator._lastResult = '';
+        Calculator._updateDisplay();
+      }
+      return;
+    }
+    const match = expr.match(/(-?\d+\.?\d*)$/);
+    if (match) {
+      const num = parseFloat(match[1]);
+      const negated = String(-num);
+      Calculator._currentExpr = expr.slice(0, expr.length - match[1].length) + negated;
+      Calculator._updateDisplay();
+    }
+  }
+
+  function renderFormulaHelper(container) {
+    const wrapper = document.createElement('div');
+    wrapper.className = 'calc-formula-helper';
+
+    const label = document.createElement('div');
+    label.className = 'calc-formula-label';
+    label.textContent = t('calculator.sci.formulas');
+
+    const select = document.createElement('select');
+    select.className = 'calc-formula-select';
+
+    const emptyOpt = document.createElement('option');
+    emptyOpt.value = '';
+    emptyOpt.textContent = t('calculator.sci.select_formula');
+    select.appendChild(emptyOpt);
+
+    FORMULAS.forEach((f, i) => {
+      const opt = document.createElement('option');
+      opt.value = String(i);
+      opt.textContent = t('calculator.sci.formula.' + f.key);
+      select.appendChild(opt);
+    });
+
+    const inputsContainer = document.createElement('div');
+    inputsContainer.className = 'calc-formula-inputs';
+
+    const resultContainer = document.createElement('div');
+    resultContainer.className = 'calc-formula-result';
+
+    select.addEventListener('change', () => {
+      while (inputsContainer.firstChild) {
+        inputsContainer.removeChild(inputsContainer.firstChild);
+      }
+      resultContainer.textContent = '';
+
+      const idx = parseInt(select.value, 10);
+      if (isNaN(idx)) return;
+
+      const formula = FORMULAS[idx];
+      renderFormulaInputs(formula, inputsContainer, resultContainer);
+    });
+
+    wrapper.append(label, select, inputsContainer, resultContainer);
+    container.appendChild(wrapper);
+  }
+
+  function renderFormulaInputs(formula, inputsEl, resultEl) {
+    const inputs = {};
+
+    formula.fields.forEach(field => {
+      const row = document.createElement('div');
+      row.className = 'calc-formula-row';
+
+      const lbl = document.createElement('label');
+      lbl.textContent = t('calculator.sci.field.' + field.key);
+
+      const inp = document.createElement('input');
+      inp.type = 'number';
+      inp.className = 'calc-formula-input';
+      inp.placeholder = '0';
+      inp.step = 'any';
+      inputs[field.key] = inp;
+
+      inp.addEventListener('input', () => {
+        recalcFormula(formula, inputs, resultEl);
+      });
+
+      row.append(lbl, inp);
+      inputsEl.appendChild(row);
+    });
+  }
+
+  function recalcFormula(formula, inputs, resultEl) {
+    const vals = {};
+    let allValid = true;
+
+    for (const field of formula.fields) {
+      const v = parseFloat(inputs[field.key].value);
+      if (isNaN(v)) { allValid = false; break; }
+      vals[field.key] = v;
+    }
+
+    if (!allValid) {
+      resultEl.textContent = '';
+      return;
+    }
+
+    const result = formula.calc(vals);
+    if (result === null || !isFinite(result)) {
+      resultEl.textContent = t('calculator.error');
+      return;
+    }
+
+    resultEl.textContent = '= ' + Calculator._formatResult(result);
+  }
+
+  function bindSciKeyboard(widgetEl) {
+    _keyboardExtHandler = (e) => {
+      if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;
+      if (e.target.contentEditable === 'true') return;
+
+      if (e.key === 'p') {
+        handleSciKey('pi');
+        e.preventDefault();
+        e.stopPropagation();
+      } else if (e.key === '^') {
+        handleSciKey('power');
+        e.preventDefault();
+        e.stopPropagation();
+      }
+    };
+    widgetEl.addEventListener('keydown', _keyboardExtHandler);
+  }
+
+  Calculator.registerMode('scientific', {
+    label: '📐',
+    shortName: 'Sci',
+    titleKey: 'calculator.tab.scientific',
+
+    render(bodyEl) {
+      bodyEl.style.padding = '8px';
+      bodyEl.style.display = 'flex';
+      bodyEl.style.flexDirection = 'column';
+      bodyEl.style.flex = '1';
+      bodyEl.style.overflow = 'hidden';
+
+      const display = document.createElement('div');
+      display.className = 'calc-display';
+
+      const exprEl = document.createElement('div');
+      exprEl.className = 'calc-expression';
+      Calculator._displayExprEl = exprEl;
+
+      const resultEl = document.createElement('div');
+      resultEl.className = 'calc-result';
+      resultEl.textContent = Calculator._lastResult || '0';
+      Calculator._displayResultEl = resultEl;
+
+      display.append(exprEl, resultEl);
+
+      const sciSection = document.createElement('div');
+      renderSciButtons(sciSection);
+
+      const stdButtons = Calculator._createButtons();
+      const historyEl = Calculator._createHistoryPanel();
+
+      const formulaSection = document.createElement('div');
+      renderFormulaHelper(formulaSection);
+
+      bodyEl.append(display, sciSection, stdButtons, historyEl, formulaSection);
+      Calculator._updateDisplay();
+
+      const entry = WidgetManager._widgets.get(Calculator.WIDGET_ID);
+      if (entry) bindSciKeyboard(entry.el);
+    },
+
+    destroy() {
+      if (_keyboardExtHandler) {
+        const entry = WidgetManager._widgets.get(Calculator.WIDGET_ID);
+        if (entry) {
+          entry.el.removeEventListener('keydown', _keyboardExtHandler);
+        }
+        _keyboardExtHandler = null;
+      }
+      Calculator._displayExprEl = null;
+      Calculator._displayResultEl = null;
+    }
+  });
+})();
diff --git a/src/js/i18n.js b/src/js/i18n.js
index 6af8df9..0039cb7 100644
--- a/src/js/i18n.js
+++ b/src/js/i18n.js
@@ -84,6 +84,21 @@ const STRINGS = {
     'calculator.history':      'History',
     'calculator.error':        'Fehler',
     'calculator.tab.standard': 'Standard',
+    'calculator.tab.scientific':         'Wissenschaftlich',
+    'calculator.sci.formulas':           'Formel-Helfer',
+    'calculator.sci.select_formula':     'Formel wählen…',
+    'calculator.sci.formula.circle_area':         'Kreisfläche (π×r²)',
+    'calculator.sci.formula.circle_circumference':'Kreisumfang (2πr)',
+    'calculator.sci.formula.celsius_to_fahrenheit':'°C → °F',
+    'calculator.sci.formula.fahrenheit_to_celsius':'°F → °C',
+    'calculator.sci.formula.pythagoras':          'Pythagoras (√(a²+b²))',
+    'calculator.sci.formula.percentage':          'Prozentwert',
+    'calculator.sci.field.radius':       'Radius',
+    'calculator.sci.field.temp':         'Temperatur',
+    'calculator.sci.field.a':            'Seite a',
+    'calculator.sci.field.b':            'Seite b',
+    'calculator.sci.field.value':        'Wert',
+    'calculator.sci.field.percent':      'Prozent',
 
     // Timer
     'timer.title':             'Timer',
@@ -393,6 +408,21 @@ const STRINGS = {
     'calculator.history':      'History',
     'calculator.error':        'Error',
     'calculator.tab.standard': 'Standard',
+    'calculator.tab.scientific':         'Scientific',
+    'calculator.sci.formulas':           'Formula Helper',
+    'calculator.sci.select_formula':     'Choose formula…',
+    'calculator.sci.formula.circle_area':         'Circle Area (π×r²)',
+    'calculator.sci.formula.circle_circumference':'Circle Circumference (2πr)',
+    'calculator.sci.formula.celsius_to_fahrenheit':'°C → °F',
+    'calculator.sci.formula.fahrenheit_to_celsius':'°F → °C',
+    'calculator.sci.formula.pythagoras':          'Pythagoras (√(a²+b²))',
+    'calculator.sci.formula.percentage':          'Percentage',
+    'calculator.sci.field.radius':       'Radius',
+    'calculator.sci.field.temp':         'Temperature',
+    'calculator.sci.field.a':            'Side a',
+    'calculator.sci.field.b':            'Side b',
+    'calculator.sci.field.value':        'Value',
+    'calculator.sci.field.percent':      'Percent',
 
     // Timer
     'timer.title':             'Timer',