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This study examined the capability of livestock producers and growers to make visual estimates of manure application rates. Manure spreader calibration was demonstrated to 101 farmers at 6 field days. At the beginning of each field demonstration, participants were asked if they had even seen this demonstration before, their occupation and their estimate of manure application based on their experience. Of the 101 participants 13% estimated at or near the actual application rate. Some (22%) estimated high application rates with 2 estimating four times the actual application rate. Most (65%) underestimated the manure application rate with 50% estimating less than onehalf the actual application rate. If relying on visual estimates, 50% of the livestock producers and growers surveyed would have applied twice the desired application rate. The tendency to underestimate manure application and therefore over-apply manure reinforces the need to calibrate spreading equipment as a part of a manure management plan.