% Transmittance → Absorbance (ftir)
Convert percent transmittance (%T) to absorbance (A) for a ftir reading. A = 2 − log₁₀(%T).
- 1A = 2 − log₁₀(%T)
A = 2 − log₁₀(10) = 1.000
🔒 100% client-side — your data is computed in the browser and never uploaded.
Cite this tool
ToolJolt. % Transmittance → Absorbance (ftir). ToolJolt Chemistry & Lab Tools; 2026. https://tooljolt.comNeed a fast, reliable % transmittance → absorbance (ftir)? This free tool computes the answer the moment the page loads and updates live as you type — no sign-up, no installs.
About % Transmittance → Absorbance (ftir)
Convert percent transmittance (%T) to absorbance (A) for a ftir reading. A = 2 − log₁₀(%T). The calculation uses A = 2 − log₁₀(%T). Why it matters: The Beer–Lambert law is only linear in a window (≈0.1–1.0 absorbance). Quantitation outside it, or with the wrong extinction coefficient, silently biases every concentration you report. Absorbance is logarithmic: 10%T = A 1.0, 1%T = A 2.0. Before you trust the number, double-check: reading absorbance above ~1.0 without diluting; using a molar ε with a mass concentration; wrong path length (not 1 cm). Everything is computed on your own device — nothing you enter is uploaded — so the tool is safe for unpublished sequences, proprietary formulations and sensitive measurements, and easy to cite in a methods section or lab SOP.
How to use % Transmittance → Absorbance (ftir)
- 1Enter your values: Transmittance.
- 2Read the headline result and the supporting figures, which recompute as you type.
- 3Open “Worked example with your numbers” to see the substituted formula step by step.
- 4Copy the result, or use the cite-this-tool snippet for your methods section.
Why use % Transmittance → Absorbance (ftir)?
- ✓Instant, client-side result — works offline once loaded and keeps your data private
- ✓Shows the worked example step by step with your own numbers, not just a final figure
- ✓Pre-filled with sensible, niche-specific defaults so it is useful the second it loads
- ✓Mobile-friendly and completely free, with no sign-up or usage caps
- ✓Built on a sourced, unit-tested formula for UV-Vis spectroscopy
Frequently asked questions
Any tips specific to this calculation?+
Absorbance is logarithmic: 10%T = A 1.0, 1%T = A 2.0. Also watch out for: reading absorbance above ~1.0 without diluting and not blanking against the correct buffer.
Is this % transmittance → absorbance (ftir) free to use?+
Yes. It is completely free, needs no sign-up, and runs entirely in your browser — there are no usage limits.
What formula does it use?+
It uses A = 2 − log₁₀(%T) The full worked example is shown beneath the result so you can verify each step.
What are the most common mistakes here?+
In UV-Vis spectroscopy, watch for: reading absorbance above ~1.0 without diluting; using a molar ε with a mass concentration; wrong path length (not 1 cm); not blanking against the correct buffer. This tool shows the working so you can catch these before they cost an experiment.
Does my data leave my device?+
No. All computation happens locally in your browser. Nothing you enter — sequences, concentrations or measurements — is uploaded to any server, so it is safe for confidential work.
Can I cite this tool?+
Yes — use the “Cite this tool” snippet on the page. Many users link these calculators from methods sections, lab SOPs and teaching materials.
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