What is let-off on a compound bow?
Let-off on a compound bow is the percentage reduction from peak draw weight to holding weight at full draw. The cams produce this drop in force near the end of the draw cycle. Higher let-off means a lighter hold for the same peak weight, though you still pull through that peak.
Calculating holding weight
Holding weight = peak draw weight x (1 - let-off / 100). A 60 lb compound with 75% let-off has a nominal holding weight of 15 lb. At 80% let-off, the same peak weight gives 12 lb. These examples show the arithmetic; measure your own bow if you need the actual force.
You can reverse the calculation: let-off % = (peak weight - holding weight) / peak weight x 100. Peak and holding readings must use the same units. A shop can measure both with an appropriate scale and draw board.
The stated percentage does not describe the entire draw cycle. Two bows with similar peak draw weight and let-off can feel different as they build force and roll over into the hold.
The valley and the back wall
The valley is the low-force region near full draw. Its width affects how much forward movement you can make before the holding force rises again. With a short valley, even a little relaxation can let the string pull your draw hand forward. A wider valley allows more movement before that increase becomes pronounced.
The back wall is the stop you feel at the end of the draw. Depending on the design, a stop contacts a cable or limb. Its feel can be firm or have some give. Keep the draw stops and modules in the manufacturer's specified positions.
Let-off, valley, and wall are related aspects of cam behavior, but one percentage cannot describe all of them. Test a bow through a controlled draw, aim, and let-down. Notice how it behaves when you leave the wall as well as when you reach it.
Choosing the holding weight
A light holding weight can reduce effort while aiming, but you still need steady posture and consistent pressure into the wall. Some archers prefer more holding weight because it helps them feel the shot. Try permitted settings at a fitted draw length, using the same release and anchor.
Do not move a draw stop outside the manual's options to create extra let-off. On some cams, changing let-off also affects draw length or requires different modules. Ask a technician to check the configuration and cam timing after the adjustment.
Questions
Does 80% let-off mean I pull only 20% of the weight?
You hold approximately 20% of peak weight once the bow reaches its intended full-draw position. Earlier in the draw, you still pass through the peak force. That distinction matters when choosing a bow: evaluate the effort needed to draw and let down, as well as the aiming hold.
Do recurves have let-off?
Conventional recurves do not have compound-style let-off. Their draw force generally increases as you pull the string farther, so the weight at your anchor is the weight you hold. A compound's cam system changes that force curve and reduces the holding load near full draw.
Will more let-off improve my accuracy?
It may make aiming more comfortable, but accuracy depends on how consistently you execute the whole shot. Too little holding resistance can feel vague to some archers. Compare groups and your ability to maintain posture with each permitted setting, and confirm the bow still fits your draw length.