Log Gamma Calculator
Free online log gamma calculator. Enter your values and get instant results with the formula, step-by-step working, a worked example and FAQs — everything runs locally in your browser on Calcton, no signup required.
中文版：对数伽马函数在线计算器
lnΓ(z) 是伽马函数的对数——避免大参数下 Γ 直接溢出，也是统计软件内部真正存储的形态。
为什么要取对数
Γ(171) = 170! ≈ 7.26×10³⁰⁶ 已贴近双精度上限，Γ(172) = 171! ≈ 1.24×10³⁰⁹ 直接溢出；而 lnΓ(172) ≈ 711.7147 稳如泰山
似然函数是一串概率密度相乘，数值很快下溢成 0——统计学一律转成对数似然相加，Γ 随之变成 lnΓ。本页用 Lanczos 近似（g = 7，9 项系数）直接计算对数而非先算 Γ 再取 log：负半轴借助反射公式 lnΓ(z) = ln(π/sin πz) − lnΓ(1−z) 回到正半轴，精度 1e-12 量级。
How to use the Log Gamma Calculator
- Fill in the inputs with your own numbers — every field shows what it expects.
- The result updates instantly as you type; no "Calculate" click needed.
- Read the result card for the main figure, the step-by-step formula, and practical notes.
Frequently asked questions
Is the Log Gamma Calculator free?
Yes — all math calculators on Calcton are free, with no sign-up required. Your inputs are processed in your browser and never sent to a server.
Is there a Chinese version of this tool?
Yes. Use the Chinese version link above — it is the same calculator with the interface in Simplified Chinese.
References
Formulas and benchmarks used by this calculator follow these published sources.
KevinContent LeadCalcton Editorial Team · Last updated 2026-09-26
Kevin maintains Calcton's formula verification and content: every calculator cites the standard it implements, worked examples are recomputed programmatically, and health benchmarks follow WHO and international guidelines.
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