Horsepower and torque are the same measurement viewed two ways, tied together by rpm. Enter either one and the rpm to get the other, in both US and metric units.
One horsepower is 33,000 foot-pounds of work per minute. Converting a turning force (torque) into work per minute brings in 2π for each revolution, and 33,000 ÷ 2π is 5,252.
For metric units, 1 hp is 0.7457 kW and 1 lb-ft is 1.3558 Nm. The same relationship holds at every point on a dyno curve, so you can use this on any rpm you read off a chart.