Flat to Incline Bench Calculator

Measured incline-bench ratios

Effect of Five Bench Inclinations on the Electromyographic Activity of the Pectoralis Major, Anterior Deltoid, and Triceps Brachii during the Bench Press Exercise — Rodríguez-Ridao et al. (2020), IJERPH 17(19):7339, DOI 10.3390/ijerph17197339. Table 1 reports the following 1RMs in 30 trained adults.

For 15°, 30°, 45° and 60°, the model divides that angle’s reported group mean by the flat mean of 81.4 kg. These are ratios of means, not published individual prediction equations.

The 10° option is a linear interpolation between the measured 0° and 15° ratios: 1 + (72.0 / 81.4 − 1) × (10 / 15). It was not directly measured. No statistical uncertainty bounds are inferred from these means. A range spanning multiple target reps describes different rep targets, not a confidence interval.

Other cited research

Arseneault, Roy and Sercia (2021) reported estimated, rather than directly measured, 1RMs extrapolated from a 12RM set in 13 men. The cited flat/30° values were 79.7/68.1 kg for close grip and 84.9/72.1 kg for wide grip. These results are retained as context; they do not set this calculator’s factors.

Lauver, Cayot and Scheuermann (2016) studied muscle activation in 14 men at −15°, 0°, 30° and 45°. EMG findings do not supply a numerical conversion factor.

Marques et al. (2025), “Load-velocity relationship in the free-weight horizontal and incline bench press”, studied 0° and 45° in 30 non-resistance-trained men. Its numerical tables have not been used to set these ratios.

Lim (2006), “The Relationship of One Repetition Maximum between Flat Bench Press Exercise and Incline Bench Press Exercise”, Korean Journal of Sport Biomechanics, studied 40 male students. The reported flat/incline means were 89.2 ± 25.9 kg and 67.1 ± 22.1 kg, with r=.969. The equation incline = −6.648 + .827 × flat (kg) is a separate regression; the abstract does not identify the incline angle, so it is not substituted for angle-specific factors.

Reps, units and rounding

For one rep, the entered weight is used directly. For 2–20 reps, the shared method is estimated 1RM = weight × (1 + reps / 30). Target rep weight = target 1RM / (1 + target reps / 30), except that one target rep uses the target 1RM directly. The older study-only incline page supports 1–10 source reps.

Epley B. (1985), “Poundage Chart,” in Boyd Epley Workout, Lincoln, NE: Body Enterprises, p. 86, is the historical chart reference supplied in the verification report. It is not peer-reviewed research. Applying it across these exercises and reversing it for target reps adds a modeling assumption.

Automatically filled input weights are shown to the nearest 1 lb or 0.5 kg. The unrounded value is retained internally until you edit that field, preventing repeated unit or direction switches from accumulating rounding errors. Rounding options affect displayed result weights. Dumbbell weights are per hand; combined weights are calculated from the rounded per-hand result.

Limits and source review

Individual results vary with technique, training experience, equipment, and range of motion. The model is for barbell pressing. Group averages do not guarantee an individual’s equivalent load.

The updated references and figures follow a user-supplied primary/publisher-source verification report. Independent primary-document retrieval remains blocked in this environment. No unsupported confidence interval or universal linear angle curve is presented.