Erro Percentual (Lab) — Calculadora Online Grátis
Calculate percent error between experimental and theoretical values
The Percent Error Calculator measures how far an experimental measurement deviates from the accepted or theoretical value, expressing the difference as a percentage. It's a standard tool in science labs — physics, chemistry, and biology experiments all require students to report percent error to assess their measurement quality. Enter your measured and theoretical values and the result is immediate.
Frequently Asked Questions
Sobre Esta Calculadora
Percent error quantifies the accuracy of a measurement or calculation compared to a known reference. It is always expressed as a positive percentage because the absolute value removes the sign — it tells you how wrong you were, not which direction. A small percent error means your measurement was close to the true value; a large one indicates significant experimental error.
The formula % Error = |Experimental − Theoretical| / |Theoretical| × 100 is the standard form used in science classes worldwide. Note that this is different from percent difference (used when neither value is the "true" reference) and percent change (used when comparing two sequential measurements of the same quantity).
Lab reports in physics, chemistry, and biology routinely require percent error calculations. Acceptable thresholds vary by field and measurement technique: 1-2% is excellent for precise lab work, while 5-10% may be acceptable for field measurements. Understanding your error sources helps improve experimental technique.
Determine seu dado prático contra a teoria de forma concisa.
Fórmula
% Error = |Experimental - Theoretical| / |Theoretical| × 100
Exemplo Resolvido
Measuring the density of aluminum in a lab experiment
Entradas:
- Experimental (measured) value: 2.65 g/cm³
- Theoretical (accepted) value: 2.70 g/cm³
Passo a Passo:
- Formula: % Error = |Experimental − Theoretical| / |Theoretical| × 100
- Difference: |2.65 − 2.70| = |−0.05| = 0.05
- Divide by theoretical: 0.05 / 2.70 = 0.01852
- Multiply by 100: 0.01852 × 100 = 1.85%
Dicas
- A percent error under 5% is generally considered acceptable in most scientific experiments.