계산 방법 Percent 오류: Lab 공식 |E − T| / |T| × 100

계산 percent error with |experimental − theoretical| / |theoretical| × 100. 일ed lab examples, signed error, and a free percent error calculator.

What Percent 오류 Asks

Percent error 비교s a measured (experimental) value to an accepted (theoretical) value. Labs use it to report how far a result sits from the known answer, as a percentage of that accepted value.

The usual school 공식 is % error = |E − T| / |T| × 100. E is experimental, T is theoretical. Absolute value makes the percent error non-negative; a signed form keeps the direction (too high or too low).

If you already have E and T and only need a 확인ed percent, open the free percent error calculator first, then return here for the denominator rule and percent-difference trap.

The 공식

  • % error = |E − T| / |T| × 100 — magnitude, always ≥ 0.
  • Signed % error = (E − T) / T × 100 — positive means E is larger than T.
  • Relative error = |E − T| / |T| — the same ratio without × 100.

    • T in the denominator is the accepted / true / theoretical value, not the average of E and T. Mixing that with percent difference is the most common lab-report 실수.

    Percent 오류 vs Percent 차이

    Percent difference 비교s two measurements of the same kind when neither is the accepted value: |A − B| / ((A + B)/2) × 100. Use percent error only when one number is the accepted theory, textbook, or known constant.

    Ordinary part-whole percents (not lab error) belong on the percentage calculator.

    단위 and Rounding

  • E and T must use the same unit before you subtract (both m, both °C, both N).
  • The % error itself is unitless (a percent).
  • T cannot be zero — you cannot divide by the accepted value.

    • Round the reported percent using your lab’s significant-figure rules. 확인 digit count with the significant figures calculator.

    풀이 예제

    예제 1: g lab, 9.7 vs 9.8

    E = 9.7 m/s², T = 9.8 m/s². |E − T| = 0.1. % error = 0.1 / 9.8 × 100 ≈ 1.02%. Signed: (9.7 − 9.8)/9.8 × 100 ≈ −1.02% (slightly low).

    예제 2: boiling point, 99.2 °C vs 100 °C

    E = 99.2, T = 100. % error = |99.2 − 100| / 100 × 100 = 0.80%.

    예제 3: 밀도, 0.89 g/cm³ vs 0.79 g/cm³

    E = 0.89, T = 0.79. % error = 0.10 / 0.79 × 100 ≈ 12.7%. Large percent error usually means a method, unit, or identity mix-up — not just rounding.

    흔한 실수

  • Putting E in the denominator instead of T.
  • Using the average of E and T (that is percent difference).
  • Leaving E and T in different 단위.
  • Dropping the absolute value when the rubric wants unsigned percent error.
  • Calling a huge percent error “close enough” without 확인ing the setup.

    • 확인 It on the 계산기

    Percent error calculator — |E − T| / |T| × 100.

    Percentage calculator — part, whole, and percent change.

    Significant figures calculator — rounding for lab reports.

    학습 % error = |E − T| / |T| × 100, then confirm every lab number on the calculator.

    문서

    • 탄성 위치 에너지 공식 (U = ½kx²): 계산기 & 예제
    • 계산 방법 전기 전력 (P = VI, I²R, V²/R)
    • 계산 방법 파동 속도 (v = fλ): 주파수 × 파장
    • 계산 방법 무게 (W = mg): 질량 vs 힘
    • 계산 방법 밀도 (ρ = m/V): 질량 ÷ Volume
    • 계산 방법 가속도 (a = (v − u)/t)

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