Analysis of the potato yield gap and the corresponding nutrient gap can help in devising strategies and measurements to increase productivity for closing the gaps through improved practices. On-farm experiments conducted in the main potato production areas of northwest China were used to determine attainable yield. Official statistical data were used to determine the actual on-farm yield. Yield gap was the difference between attainable yield and actual on-farm yield. Nutrient gap was calculated by dividing the size of yield gap by partial factor productivity. Results indicated that nitrogen (N), phosphorus (P) and potassium (K) fertilization increased potato yield by an average of 1169–7625, 2937–5336 and 2331–7338 kg/ha, respectively. The maximum attainable yields (the 90th percentile yields) were 50 145, 37 855, 30 261 and 56 616 kg/ha and the average actual on-farm yield were 14 179, 16 732, 10 271 and 19 990 kg/ha in the Inner Mongolia Autonomous Region (IMAR), Gansu, Ningxia and Qinghai provinces, respectively. In the above four regions, yield would need to increase by 165, 70, 112 and 121% from actual yield to reach 75% of attainable yield. Compared with recent 3-year average NPK rates by farmers, the total NPK rates need to increase by 90.1–134.3% for IMAR, 42.9–69.2% for Gansu, 68.1–111.2% for Ningxia and 48.1–83.8% for Qinghai to improve productivity to near the 75% attainable yield. In conclusion, the high yield responses to fertilizer application provide opportunities to close the large yield gaps through balanced nutrition.