Percent Error Calculator
Measure how far a result is from an accepted value, with the ABS formula that works in Excel and Google Sheets.
Numbers stay in your browser. The default is a measured 48 against an accepted 50, which is a 4% error.
Quick answer: percent error is the absolute difference between a measured value and an accepted value, divided by the accepted value. In Excel or Google Sheets, with the measurement in B2 and the accepted value in C2:
=ABS(B2-C2)/ABS(C2)Format the cell as a percentage. This is not a percentage change, which keeps the sign and compares a new number to an old one, and it is not a share of a total.
48 against 50
The difference is 2, and 2 ÷ 50 = 0.04, or 4%. In Google Sheets on 12 November 2026, =ABS(48-50)/ABS(50) returned 0.04 exactly. A tighter lab-style pair, 9.8 against 9.81, gave =ABS(9.8-9.81)/ABS(9.81) = 0.0010193679918450342, about 0.1019%.
The formula can be larger than 100%. A measured 150 against an accepted 50 is =ABS(150-50)/ABS(50), which returned 2 (200%). If the accepted value is 0, the division is undefined and a sheet shows #DIV/0!.
Why the absolute value is there
Lab reports usually want the size of the miss, not whether you came in high or low. ABS makes 48 vs 50 and 52 vs 50 the same 4% error. If you need the direction as well, keep a signed helper, =B2-C2, next to the percent error. This calculator reports both: the signed error for 48 vs 50 is −2, and the absolute error is 2.
ABS in the denominator handles a negative accepted value (a temperature below zero, for example) so the percent stays positive. What you cannot do is put zero in that denominator.
Questions that come up
What is the percent error formula in Excel or Google Sheets?
With the measured value in B2 and the accepted value in C2, use =ABS(B2-C2)/ABS(C2) and format the result as a percentage. The accepted value cannot be zero.
Is percent error the same as percentage change?
No. Percentage change compares a new value to an old one and keeps the sign (up or down). Percent error asks how far a measurement is from a known or accepted value, and the usual formula takes the absolute value, so the result is not negative.
Can percent error be more than 100%?
Yes. A measured 150 against an accepted 50 is a 200% error: =ABS(150-50)/ABS(50) returns 2.