作为程序员，没有合适的工具，就得手搓一个，PC端，移动端均可适用。废话不多说，直接上代码。
HTML:
<div class="calculator">
<label for="loanAmount">贷款金额 (元)：</label>
<input id="loanAmount" type="number" placeholder="输入贷款金额">
<label for="interestRate">年利率 (%)：</label>
<input id="interestRate" type="number" placeholder="输入年利率">
<label for="loanTerm">贷款年限 (年)：</label>
<input id="loanTerm" type="number" placeholder="输入贷款年限">
<button onclick="calculateRepayment()">计算还款额</button>
<div id="result" class="result">结果将显示在这里</div>
</div>
<div class="guide">
<pre>操作指南<br><br>
1. 输入贷款金额、年利率和贷款年限。<br><br>
2. 点击“计算还款额”按钮，计算每月还款额和总还款额。
</pre>
</div>JS:
javascript"> function calculateRepayment() {const loanAmount = parseFloat(document.getElementById('loanAmount').value);const interestRate = parseFloat(document.getElementById('interestRate').value) / 100 / 12; // 将年利率转换为月利率const loanTerm = parseInt(document.getElementById('loanTerm').value) * 12; // 将贷款年限转换为月数if (isNaN(loanAmount) || isNaN(interestRate) || isNaN(loanTerm)) {document.getElementById('result').textContent = "请输入有效的贷款金额、利率和年限。";return;}// 等额本息还款公式：每月还款额 = [贷款金额 × 月利率 × (1 + 月利率)^还款月数] / [(1 + 月利率)^还款月数 - 1]const monthlyRepayment = (loanAmount * interestRate * Math.pow(1 + interestRate, loanTerm)) / (Math.pow(1 + interestRate, loanTerm) - 1);const totalRepayment = monthlyRepayment * loanTerm;document.getElementById('result').innerHTML = `每月还款额：${monthlyRepayment.toFixed(2)} 元<br>` +`总还款额：${totalRepayment.toFixed(2)} 元`;}CSS:
.calculator {width: 100%;background-color: #333;color: white;padding: 20px;border-radius: 10px;box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}label {display: block;margin-bottom: 10px;font-size: 16px;
}input, select {width: 100%!important;padding: 10px!important;margin-bottom: 20px;color: #000000; border-radius: 5px;border: 1px solid #555;font-size: 16px!important;background-color: #ffffff!important;
}button {width: 100%;padding: 10px;background-color: #007bff;color: white;border: none;border-radius: 5px;cursor: pointer;font-size: 16px;
}button:hover {background-color: orange;
}.result {font-size: 18px;margin-top: 20px;text-align: center;
}option {background-color: #ffffff;
}p {font-size: 18px;margin-top: 5px!important;
}线上运行，可以直接打开：还款计算器
