diff --git a/newtab.html b/newtab.html
index c6bc824..48f05d2 100644
--- a/newtab.html
+++ b/newtab.html
@@ -511,6 +511,7 @@
   <script src="src/js/calc-converter.js"></script>
   <script src="src/js/calc-satisfactory.js"></script>
   <script src="src/js/calc-factorio.js"></script>
+  <script src="src/js/calc-stationeers.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 4233370..8fd074f 100644
--- a/src/css/main.css
+++ b/src/css/main.css
@@ -1534,6 +1534,47 @@ body.show-desc .bm-desc { display: block; }
   gap: 4px;
 }
 
+/* Calculator Stationeers specifics */
+.calc-game-hint {
+  font-size: 10px;
+  color: var(--text-muted);
+  font-style: italic;
+  margin-top: -4px;
+  text-align: right;
+}
+.calc-game-details {
+  border-top: 1px solid var(--border);
+  padding-top: 6px;
+  margin-top: 4px;
+}
+.calc-game-details summary {
+  font-size: 10px;
+  color: var(--text-muted);
+  cursor: pointer;
+  text-transform: uppercase;
+  letter-spacing: 0.5px;
+}
+.calc-game-table {
+  width: 100%;
+  font-size: 11px;
+  border-collapse: collapse;
+  margin-top: 4px;
+}
+.calc-game-table th {
+  text-align: left;
+  color: var(--text-muted);
+  font-weight: 600;
+  padding: 2px 6px;
+  border-bottom: 1px solid var(--border);
+}
+.calc-game-table td {
+  padding: 2px 6px;
+  color: var(--text-secondary);
+}
+.calc-game-table tr:nth-child(even) td {
+  background: rgba(0,0,0,0.1);
+}
+
 /* ============================================
    TIMER WIDGET
    ============================================ */
diff --git a/src/js/calc-stationeers.js b/src/js/calc-stationeers.js
new file mode 100644
index 0000000..842b1f5
--- /dev/null
+++ b/src/js/calc-stationeers.js
@@ -0,0 +1,361 @@
+/* =============================================
+   HELLION NEWTAB — calc-stationeers.js
+   Stationeers Calculator Modus
+   ============================================= */
+
+(function() {
+  'use strict';
+
+  const R = 8314.46261815324;
+  const COMBUSTION_ENERGY = 563452;
+  const HEAT_CAP_PURE_FUEL = 61.9;
+  const HEAT_CAP_DELTA = 172.615;
+  const BATTERY_CAPACITY = 50000;
+
+  const HEAT_CAPS = [
+    { gas: 'O\u2082',        cp: 21.1 },
+    { gas: 'H\u2082',        cp: 20.4 },
+    { gas: 'CO\u2082',       cp: 28.2 },
+    { gas: 'N\u2082',        cp: 20.6 },
+    { gas: 'H\u2082O',       cp: 72.0 },
+    { gas: 'N\u2082O',       cp: 23.0 },
+    { gas: 'Pollutant', cp: 24.8 }
+  ];
+
+  const GAS_VARS = ['P', 'V', 'n', 'T'];
+  const SUB_MODES = ['gas', 'furnace', 'solar', 'atmo'];
+  let _activeSubMode = 'gas';
+
+  function createField(labelKey, defaultVal, opts) {
+    opts = opts || {};
+    const row = document.createElement('div');
+    row.className = 'calc-game-field';
+    const label = document.createElement('label');
+    label.textContent = t(labelKey);
+    const input = document.createElement('input');
+    input.type = 'number';
+    input.className = 'calc-game-input';
+    input.value = defaultVal;
+    if (opts.step) input.step = opts.step;
+    if (opts.min !== undefined) input.min = opts.min;
+    if (opts.max !== undefined) input.max = opts.max;
+    if (opts.disabled) input.disabled = true;
+    row.append(label, input);
+    return { row, input };
+  }
+
+  function createOutput(labelKey) {
+    const row = document.createElement('div');
+    row.className = 'calc-game-output';
+    const label = document.createElement('span');
+    label.textContent = t(labelKey);
+    const value = document.createElement('span');
+    value.className = 'calc-game-value';
+    row.append(label, value);
+    return { row, value };
+  }
+
+  function renderGas(container) {
+    const solveRow = document.createElement('div');
+    solveRow.className = 'calc-game-field';
+    const solveLabel = document.createElement('label');
+    solveLabel.textContent = t('calculator.sta.solve_for');
+    const solveSelect = document.createElement('select');
+    solveSelect.className = 'calc-game-input';
+
+    GAS_VARS.forEach(v => {
+      const opt = document.createElement('option');
+      opt.value = v;
+      opt.textContent = t('calculator.sta.var.' + v);
+      solveSelect.appendChild(opt);
+    });
+
+    solveRow.append(solveLabel, solveSelect);
+    container.appendChild(solveRow);
+
+    const fields = {};
+    const defaults = { P: 101.325, V: 1000, n: 1, T: 293.15 };
+
+    GAS_VARS.forEach(v => {
+      const f = createField(
+        'calculator.sta.var.' + v + '_label',
+        defaults[v],
+        { step: 'any' }
+      );
+      fields[v] = f;
+      container.appendChild(f.row);
+    });
+
+    const tempHelper = document.createElement('div');
+    tempHelper.className = 'calc-game-hint';
+    container.appendChild(tempHelper);
+
+    const resultOutput = createOutput('calculator.sta.result');
+    container.appendChild(resultOutput.row);
+
+    function calc() {
+      const solveFor = solveSelect.value;
+
+      GAS_VARS.forEach(v => {
+        fields[v].input.disabled = (v === solveFor);
+        fields[v].input.style.opacity = (v === solveFor) ? '0.5' : '1';
+      });
+
+      const P_kPa = parseFloat(fields.P.input.value) || 0;
+      const P = P_kPa * 1000;
+      const V = parseFloat(fields.V.input.value) || 0;
+      const n = parseFloat(fields.n.input.value) || 0;
+      const T = parseFloat(fields.T.input.value) || 0;
+
+      let result = null;
+      let unit = '';
+
+      switch (solveFor) {
+        case 'P':
+          if (V > 0) { result = (n * R * T) / V; result /= 1000; unit = 'kPa'; }
+          break;
+        case 'V':
+          if (P > 0) { result = (n * R * T) / P; unit = 'L'; }
+          break;
+        case 'n':
+          if (R * T > 0) { result = (P * V) / (R * T); unit = 'mol'; }
+          break;
+        case 'T':
+          if (n * R > 0) { result = (P * V) / (n * R); unit = 'K'; }
+          break;
+      }
+
+      if (result !== null && isFinite(result)) {
+        fields[solveFor].input.value = Calculator._formatResult(result);
+        resultOutput.value.textContent = Calculator._formatResult(result) + ' ' + unit;
+      } else {
+        resultOutput.value.textContent = '-';
+      }
+
+      const tempVal = parseFloat(fields.T.input.value) || 0;
+      tempHelper.textContent = Calculator._formatResult(tempVal - 273.15) + ' \u00B0C';
+    }
+
+    GAS_VARS.forEach(v => {
+      fields[v].input.addEventListener('input', calc);
+    });
+    solveSelect.addEventListener('change', calc);
+    calc();
+  }
+
+  function renderFurnace(container) {
+    const fuelField = createField('calculator.sta.fuel_ratio', 0.5, { step: 0.01, min: 0, max: 1 });
+    const tempField = createField('calculator.sta.start_temp', 293.15, { step: 1, min: 0 });
+    const pressField = createField('calculator.sta.start_pressure', 101.325, { step: 0.1, min: 0 });
+
+    const tempOutput = createOutput('calculator.sta.temp_after');
+    const pressOutput = createOutput('calculator.sta.pressure_after');
+    const warningEl = document.createElement('div');
+    warningEl.className = 'calc-game-warning';
+
+    function calc() {
+      const fuel = parseFloat(fuelField.input.value) || 0;
+      const T_vor = parseFloat(tempField.input.value) || 293.15;
+      const P_vor = parseFloat(pressField.input.value) || 101.325;
+
+      warningEl.textContent = '';
+      if (fuel < 0.05) {
+        warningEl.textContent = t('calculator.sta.warn_low_fuel');
+      }
+      if (P_vor < 10) {
+        warningEl.textContent += (warningEl.textContent ? ' ' : '') + t('calculator.sta.warn_low_pressure');
+      }
+
+      const specificHeat = HEAT_CAP_PURE_FUEL;
+      const T_nach = (T_vor * specificHeat + fuel * COMBUSTION_ENERGY) / (specificHeat + fuel * HEAT_CAP_DELTA);
+      const P_nach = P_vor * T_nach * (1 + 5.7 * fuel) / T_vor;
+
+      tempOutput.value.textContent = Calculator._formatResult(T_nach) + ' K (' + Calculator._formatResult(T_nach - 273.15) + ' \u00B0C)';
+      pressOutput.value.textContent = Calculator._formatResult(P_nach) + ' kPa';
+    }
+
+    [fuelField, tempField, pressField].forEach(f => f.input.addEventListener('input', calc));
+
+    container.append(fuelField.row, tempField.row, pressField.row, warningEl, tempOutput.row, pressOutput.row);
+    calc();
+  }
+
+  function renderSolar(container) {
+    const panelField = createField('calculator.sta.panels', 12, { step: 1, min: 1 });
+    const wattField = createField('calculator.sta.watts_per_panel', 500, { step: 10, min: 1 });
+    const dayField = createField('calculator.sta.day_length', 600, { step: 1, min: 1 });
+    const nightField = createField('calculator.sta.night_length', 600, { step: 1, min: 1 });
+    const consumeField = createField('calculator.sta.consumption', 2000, { step: 10, min: 0 });
+
+    const genOutput = createOutput('calculator.sta.generation');
+    const surplusOutput = createOutput('calculator.sta.surplus');
+    const nightOutput = createOutput('calculator.sta.night_energy');
+    const battOutput = createOutput('calculator.sta.batteries_needed');
+
+    function calc() {
+      const panels = parseFloat(panelField.input.value) || 0;
+      const wpp = parseFloat(wattField.input.value) || 0;
+      const nightLen = parseFloat(nightField.input.value) || 0;
+      const consume = parseFloat(consumeField.input.value) || 0;
+
+      const generation = panels * wpp;
+      const surplus = generation - consume;
+      const nightEnergy = consume * nightLen;
+      const batteries = nightEnergy > 0 ? Math.ceil(nightEnergy / BATTERY_CAPACITY) : 0;
+
+      genOutput.value.textContent = Calculator._formatResult(generation) + ' W';
+
+      surplusOutput.value.textContent = Calculator._formatResult(surplus) + ' W';
+      if (surplus < 0) {
+        surplusOutput.value.style.color = 'var(--danger)';
+      } else {
+        surplusOutput.value.style.color = '';
+      }
+
+      nightOutput.value.textContent = Calculator._formatResult(nightEnergy) + ' Ws';
+      battOutput.value.textContent = batteries;
+    }
+
+    [panelField, wattField, dayField, nightField, consumeField].forEach(f => f.input.addEventListener('input', calc));
+
+    container.append(panelField.row, wattField.row, dayField.row, nightField.row, consumeField.row,
+                     genOutput.row, surplusOutput.row, nightOutput.row, battOutput.row);
+    calc();
+  }
+
+  function renderAtmo(container) {
+    const targetField = createField('calculator.sta.target_temp', 293.15, { step: 1 });
+    const gas1Field = createField('calculator.sta.gas1_temp', 200, { step: 1 });
+    const gas2Field = createField('calculator.sta.gas2_temp', 400, { step: 1 });
+
+    const m1Output = createOutput('calculator.sta.mixer_input1');
+    const m2Output = createOutput('calculator.sta.mixer_input2');
+
+    function calc() {
+      const T0 = parseFloat(targetField.input.value) || 0;
+      const T1 = parseFloat(gas1Field.input.value) || 0;
+      const T2 = parseFloat(gas2Field.input.value) || 0;
+
+      const denom = Math.abs(T1 - T0) + Math.abs(T2 - T0);
+      if (denom === 0) {
+        m1Output.value.textContent = '50%';
+        m2Output.value.textContent = '50%';
+        return;
+      }
+
+      const M1 = Math.abs(T2 - T0) / denom;
+      const M2 = 1 - M1;
+
+      m1Output.value.textContent = Calculator._formatResult(M1 * 100) + '%';
+      m2Output.value.textContent = Calculator._formatResult(M2 * 100) + '%';
+    }
+
+    [targetField, gas1Field, gas2Field].forEach(f => f.input.addEventListener('input', calc));
+
+    container.append(targetField.row, gas1Field.row, gas2Field.row, m1Output.row, m2Output.row);
+    calc();
+
+    const details = document.createElement('details');
+    details.className = 'calc-game-details';
+
+    const summary = document.createElement('summary');
+    summary.textContent = t('calculator.sta.heat_cap_ref');
+    details.appendChild(summary);
+
+    const table = document.createElement('table');
+    table.className = 'calc-game-table';
+
+    const thead = document.createElement('thead');
+    const headerRow = document.createElement('tr');
+    const thGas = document.createElement('th');
+    thGas.textContent = t('calculator.sta.gas');
+    const thCp = document.createElement('th');
+    thCp.textContent = 'Cp (J/mol\u00B7K)';
+    headerRow.append(thGas, thCp);
+    thead.appendChild(headerRow);
+
+    const tbody = document.createElement('tbody');
+    HEAT_CAPS.forEach(entry => {
+      const tr = document.createElement('tr');
+      const tdGas = document.createElement('td');
+      tdGas.textContent = entry.gas;
+      const tdCp = document.createElement('td');
+      tdCp.textContent = entry.cp;
+      tr.append(tdGas, tdCp);
+      tbody.appendChild(tr);
+    });
+
+    table.append(thead, tbody);
+    details.appendChild(table);
+    container.appendChild(details);
+  }
+
+  async function loadState() {
+    const data = await Store.get(Calculator.STORAGE_KEY);
+    if (data && data.calculator && data.calculator.stationeers) {
+      const s = data.calculator.stationeers;
+      if (s.lastSubMode && SUB_MODES.includes(s.lastSubMode)) _activeSubMode = s.lastSubMode;
+    }
+  }
+
+  async function saveState() {
+    const data = await Store.get(Calculator.STORAGE_KEY) || {};
+    if (!data.calculator) data.calculator = {};
+    data.calculator.stationeers = { lastSubMode: _activeSubMode };
+    await Store.set(Calculator.STORAGE_KEY, data);
+  }
+
+  function renderSubMode(container) {
+    container.textContent = '';
+    switch (_activeSubMode) {
+      case 'gas':     renderGas(container); break;
+      case 'furnace': renderFurnace(container); break;
+      case 'solar':   renderSolar(container); break;
+      case 'atmo':    renderAtmo(container); break;
+    }
+  }
+
+  Calculator.registerMode('stationeers', {
+    label: '\uD83D\uDE80',
+    shortName: 'STA',
+    titleKey: 'calculator.tab.stationeers',
+
+    render(bodyEl) {
+      bodyEl.style.padding = '8px';
+      bodyEl.style.display = 'flex';
+      bodyEl.style.flexDirection = 'column';
+      bodyEl.style.gap = '8px';
+
+      loadState().then(() => {
+        const subContent = document.createElement('div');
+        subContent.className = 'calc-game-content';
+
+        const bar = document.createElement('div');
+        bar.className = 'calc-game-subtabs';
+
+        SUB_MODES.forEach(mode => {
+          const btn = document.createElement('button');
+          btn.type = 'button';
+          btn.className = 'calc-game-subtab' + (mode === _activeSubMode ? ' active' : '');
+          btn.textContent = t('calculator.sta.tab.' + mode);
+          btn.dataset.mode = mode;
+          btn.addEventListener('click', () => {
+            bar.querySelectorAll('.calc-game-subtab').forEach(b => b.classList.remove('active'));
+            btn.classList.add('active');
+            _activeSubMode = mode;
+            renderSubMode(subContent);
+            saveState();
+          });
+          bar.appendChild(btn);
+        });
+
+        bodyEl.append(bar, subContent);
+        renderSubMode(subContent);
+      });
+    },
+
+    destroy() {
+      saveState();
+    }
+  });
+})();
diff --git a/src/js/i18n.js b/src/js/i18n.js
index ca0722d..6a213a0 100644
--- a/src/js/i18n.js
+++ b/src/js/i18n.js
@@ -148,6 +148,46 @@ const STRINGS = {
     'calculator.fac.belt_needed':        'Belt benötigt',
     'calculator.fac.exceeds_belt':       'Übersteigt max. Belt',
 
+    // Stationeers Calculator
+    'calculator.tab.stationeers':        'Stationeers',
+    'calculator.sta.tab.gas':            'Gas',
+    'calculator.sta.tab.furnace':        'Ofen',
+    'calculator.sta.tab.solar':          'Solar',
+    'calculator.sta.tab.atmo':           'Atmo',
+    'calculator.sta.solve_for':          'Gesucht',
+    'calculator.sta.var.P':              'Druck (P)',
+    'calculator.sta.var.V':              'Volumen (V)',
+    'calculator.sta.var.n':              'Stoffmenge (n)',
+    'calculator.sta.var.T':              'Temperatur (T)',
+    'calculator.sta.var.P_label':        'Druck (kPa)',
+    'calculator.sta.var.V_label':        'Volumen (L)',
+    'calculator.sta.var.n_label':        'Stoffmenge (mol)',
+    'calculator.sta.var.T_label':        'Temperatur (K)',
+    'calculator.sta.result':             'Ergebnis',
+    'calculator.sta.fuel_ratio':         'Fuel-Anteil (0-1)',
+    'calculator.sta.start_temp':         'Start-Temperatur (K)',
+    'calculator.sta.start_pressure':     'Start-Druck (kPa)',
+    'calculator.sta.temp_after':         'T nach Zündung',
+    'calculator.sta.pressure_after':     'P nach Zündung',
+    'calculator.sta.warn_low_fuel':      '\u26A0 Fuel unter 5%',
+    'calculator.sta.warn_low_pressure':  '\u26A0 Druck unter 10 kPa',
+    'calculator.sta.panels':             'Anzahl Panels',
+    'calculator.sta.watts_per_panel':    'Watt/Panel',
+    'calculator.sta.day_length':         'Taglänge (s)',
+    'calculator.sta.night_length':       'Nachtlänge (s)',
+    'calculator.sta.consumption':        'Verbrauch (W)',
+    'calculator.sta.generation':         'Erzeugung',
+    'calculator.sta.surplus':            'Überschuss',
+    'calculator.sta.night_energy':       'Nacht-Energie',
+    'calculator.sta.batteries_needed':   'Batterien benötigt',
+    'calculator.sta.target_temp':        'Ziel-Temperatur (K)',
+    'calculator.sta.gas1_temp':          'Gas 1 Temperatur (K)',
+    'calculator.sta.gas2_temp':          'Gas 2 Temperatur (K)',
+    'calculator.sta.mixer_input1':       'Mixer Input 1',
+    'calculator.sta.mixer_input2':       'Mixer Input 2',
+    'calculator.sta.heat_cap_ref':       'Wärmekapazitäten (Referenz)',
+    'calculator.sta.gas':                'Gas',
+
     // Timer
     'timer.title':             'Timer',
     'timer.start':             'Start',
@@ -520,6 +560,46 @@ const STRINGS = {
     'calculator.fac.belt_needed':        'Belt needed',
     'calculator.fac.exceeds_belt':       'Exceeds max belt',
 
+    // Stationeers Calculator
+    'calculator.tab.stationeers':        'Stationeers',
+    'calculator.sta.tab.gas':            'Gas',
+    'calculator.sta.tab.furnace':        'Furnace',
+    'calculator.sta.tab.solar':          'Solar',
+    'calculator.sta.tab.atmo':           'Atmo',
+    'calculator.sta.solve_for':          'Solve for',
+    'calculator.sta.var.P':              'Pressure (P)',
+    'calculator.sta.var.V':              'Volume (V)',
+    'calculator.sta.var.n':              'Amount (n)',
+    'calculator.sta.var.T':              'Temperature (T)',
+    'calculator.sta.var.P_label':        'Pressure (kPa)',
+    'calculator.sta.var.V_label':        'Volume (L)',
+    'calculator.sta.var.n_label':        'Amount (mol)',
+    'calculator.sta.var.T_label':        'Temperature (K)',
+    'calculator.sta.result':             'Result',
+    'calculator.sta.fuel_ratio':         'Fuel Ratio (0-1)',
+    'calculator.sta.start_temp':         'Start Temperature (K)',
+    'calculator.sta.start_pressure':     'Start Pressure (kPa)',
+    'calculator.sta.temp_after':         'T after ignition',
+    'calculator.sta.pressure_after':     'P after ignition',
+    'calculator.sta.warn_low_fuel':      '\u26A0 Fuel below 5%',
+    'calculator.sta.warn_low_pressure':  '\u26A0 Pressure below 10 kPa',
+    'calculator.sta.panels':             'Panel Count',
+    'calculator.sta.watts_per_panel':    'Watts/Panel',
+    'calculator.sta.day_length':         'Day Length (s)',
+    'calculator.sta.night_length':       'Night Length (s)',
+    'calculator.sta.consumption':        'Consumption (W)',
+    'calculator.sta.generation':         'Generation',
+    'calculator.sta.surplus':            'Surplus',
+    'calculator.sta.night_energy':       'Night Energy',
+    'calculator.sta.batteries_needed':   'Batteries needed',
+    'calculator.sta.target_temp':        'Target Temperature (K)',
+    'calculator.sta.gas1_temp':          'Gas 1 Temperature (K)',
+    'calculator.sta.gas2_temp':          'Gas 2 Temperature (K)',
+    'calculator.sta.mixer_input1':       'Mixer Input 1',
+    'calculator.sta.mixer_input2':       'Mixer Input 2',
+    'calculator.sta.heat_cap_ref':       'Heat Capacities (Reference)',
+    'calculator.sta.gas':                'Gas',
+
     // Timer
     'timer.title':             'Timer',
     'timer.start':             'Start',