<b><i>Background:</i></b> Acute liver failure (ALF) occurs as a rare, sudden, extensive loss of liver function in a previously healthy liver. In advanced cases, ALF may require liver transplantation (LT). Available prognostic parameters have limited accuracy to decide, which patient to consider for LT. The liver maximum function capacity test (LiMAx) can accurately determine liver function and was assessed as predictor of survival, along with coagulation parameters and liver stiffness in nonacetaminophen-induced ALF. <b><i>Methods:</i></b> Various liver function tests, including LiMAx measurements, coagulation factors, and transient elastography (TE), were analyzed retrospectively for associations with clinical outcome in 34 patients with ALF or acute hepatitis (AH). Data were compared between patients with spontaneous recovery (SR) and non-SR (3-month mortality/LT; NSR). <b><i>Results:</i></b> The analysis included 34 patients (22 ALF, 12 AH; 19 males, 15 females; age 36.7 ± 14.6 years) with drug-induced liver injury (DILI) (<i>n</i> = 12), autoimmune hepatitis (AIH; <i>n</i> = 13), AIH-DILI overlap (<i>n</i> = 1), viral (<i>n</i> = 9), or cryptogenic liver failure (<i>n</i> = 1). Thirty-one patients recovered spontaneously, 2 patients died, and 1 patient underwent LT. The LiMAx was 197.6 (±68.4) for SR versus 92.33 (±65.0) for NSR (<i>p</i> = 0.0157). Fibrinogen was significantly lower in patients with NSR than in SR patients (209.0 vs. 106.3; <i>p</i> = 0.02). Mean liver stiffness measured by TE was 39.3 for NSR and 17.3 for SR (<i>p</i> = 0.26). KCC was fulfilled in only 4 patients (3 SR, 1 NSR). LiMAx results correlated positively with serum fibrinogen and antithrombin III concentrations and correlated negatively with liver stiffness. No other analyzed factor could differentiate between SR and NSR. <b><i>Conclusion:</i></b> Decision-making in ALF remains challenging. LiMAx and fibrinogen might predict the prognosis in patients with nonacetaminophen-induced ALF and in combination could be feasible tools to decide if LT is necessary.