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Percentage Calculator

Whether you’re figuring out a restaurant tip, calculating a sale discount, or tracking how much your expenses changed month over month, percentages come up constantly in everyday life. This free calculator gives you five dedicated modes so you always get the right answer — no mental math required.

<!-- TAB 1: What is X% of Y? -->
<div id="t1" class="pct-panel active">
  <h3>What is X% of Y?</h3>
  <div class="pct-row">
    <label>Percentage (%)</label>
    <input type="number" id="t1-pct" placeholder="e.g. 15" min="0" step="any">
    <span class="unit">%</span>
  </div>
  <div class="pct-row">
    <label>of Number</label>
    <input type="number" id="t1-num" placeholder="e.g. 200" step="any">
  </div>
  <button class="pct-btn" onclick="calcT1()">Calculate</button>
  <div class="pct-result" id="t1-result">
    <div class="res-main" id="t1-main"></div>
    <div class="res-formula" id="t1-formula"></div>
  </div>
</div>

<!-- TAB 2: X is what % of Y? -->
<div id="t2" class="pct-panel">
  <h3>X is what % of Y?</h3>
  <div class="pct-row">
    <label>Number X</label>
    <input type="number" id="t2-x" placeholder="e.g. 30" step="any">
  </div>
  <div class="pct-row">
    <label>Number Y</label>
    <input type="number" id="t2-y" placeholder="e.g. 200" step="any">
  </div>
  <button class="pct-btn" onclick="calcT2()">Calculate</button>
  <div class="pct-result" id="t2-result">
    <div class="res-main" id="t2-main"></div>
    <div class="res-formula" id="t2-formula"></div>
  </div>
</div>

<!-- TAB 3: % Change -->
<div id="t3" class="pct-panel">
  <h3>Percentage Change</h3>
  <div class="pct-row">
    <label>Original Value</label>
    <input type="number" id="t3-orig" placeholder="e.g. 80" step="any">
  </div>
  <div class="pct-row">
    <label>New Value</label>
    <input type="number" id="t3-new" placeholder="e.g. 100" step="any">
  </div>
  <button class="pct-btn" onclick="calcT3()">Calculate</button>
  <div class="pct-result" id="t3-result">
    <div class="res-main" id="t3-main"></div>
    <div class="res-formula" id="t3-formula"></div>
  </div>
</div>

<!-- TAB 4: Tip Calculator -->
<div id="t4" class="pct-panel">
  <h3>Tip Calculator</h3>
  <div class="pct-row">
    <label>Bill Amount ($)</label>
    <input type="number" id="t4-bill" placeholder="e.g. 85.00" min="0" step="0.01" oninput="calcT4()">
    <span class="unit">$</span>
  </div>
  <div class="pct-slider-row">
    <label>Tip Percentage</label>
    <input type="range" id="t4-tip-slider" min="0" max="30" value="18" step="1" oninput="t4SliderUpdate()">
    <span class="slider-val" id="t4-tip-display">18%</span>
  </div>
  <div class="pct-slider-row">
    <label>Split Between</label>
    <input type="range" id="t4-people-slider" min="1" max="20" value="1" step="1" oninput="t4PeopleUpdate()">
    <span class="slider-val" id="t4-people-display">1 person</span>
  </div>
  <button class="pct-btn" onclick="calcT4()">Calculate</button>
  <div class="pct-multi-result" id="t4-result">
    <div class="pct-card">
      <div class="card-label">Tip Amount</div>
      <div class="card-val" id="t4-tip-amt">—</div>
    </div>
    <div class="pct-card">
      <div class="card-label">Total Bill</div>
      <div class="card-val" id="t4-total">—</div>
    </div>
    <div class="pct-card highlight">
      <div class="card-label">Per Person</div>
      <div class="card-val" id="t4-per-person">—</div>
    </div>
  </div>
</div>

<!-- TAB 5: Discount Calculator -->
<div id="t5" class="pct-panel">
  <h3>Discount Calculator</h3>
  <div class="pct-row">
    <label>Original Price ($)</label>
    <input type="number" id="t5-price" placeholder="e.g. 120.00" min="0" step="0.01" oninput="calcT5()">
    <span class="unit">$</span>
  </div>
  <div class="pct-slider-row">
    <label>Discount</label>
    <input type="range" id="t5-disc-slider" min="5" max="90" value="20" step="1" oninput="t5SliderUpdate()">
    <span class="slider-val" id="t5-disc-display">20%</span>
  </div>
  <button class="pct-btn" onclick="calcT5()">Calculate</button>
  <div class="pct-multi-result" id="t5-result">
    <div class="pct-card">
      <div class="card-label">Discount Amount</div>
      <div class="card-val" id="t5-disc-amt">—</div>
    </div>
    <div class="pct-card">
      <div class="card-label">Final Price</div>
      <div class="card-val" id="t5-final">—</div>
    </div>
    <div class="pct-card highlight">
      <div class="card-label">You Save</div>
      <div class="card-val" id="t5-save">—</div>
    </div>
  </div>
</div>

Quick Percentage Reference

% of amount$50$100$500$1,000
10%$5.00$10.00$50.00$100.00
15%$7.50$15.00$75.00$150.00
20%$10.00$20.00$100.00$200.00
25%$12.50$25.00$125.00$250.00
33%$16.50$33.00$165.00$330.00
50%$25.00$50.00$250.00$500.00
75%$37.50$75.00$375.00$750.00