Digital gauges can be just as inaccurate as an analog gauge. I got three new analog gauges connected to a common manifold to agree within 2psi, which made me confident in all three. A plus or minus 1.5 psi accuracy winters gauge is about $20 on Amazon. A plus or minus 1 psi gauge with a certificate of accuracy is about $130 at McMaster-Carr. The winters gauges are good enough for me.