This is a tip for making your own 1nF capacitor if you wish to test calibration of lowest measuring range regarding capacitance in your DMM.
In case that you own HIOKI DT4282 or Keysight U1272A which both have rich display resolution, if you connect over they input one Pomona 2BC-36 cable assembly, then you may expect a measurement of 0.8nF to 1.1nF .
Such min-max (tolerance) this is a proof that your meter this is well calibrated.
2BC-36 cable assembly this is no other than two double banana plugs and RG58 at a length of 91.5 cm. https://www.pomonaelectronics.com/products/cables/coaxial-and-rf-cables/double-banana-plugs-rg58cuNow instead buying such cable assembly you may consider making your own.
Parts that you may seek alternatively this is a double banana to BNC and one BNC to BNC (RG58) cable no longer than 90cm.
I did run this test today and I discovered that my HIOKI DT4282 this does one ultra fast measurement compared to U1272A which requiring 7~8 second so measurement to stabilize on screen.
Just for the fun of it I did test also Fluke 28II, and I did rediscover for once more time that
this does not have necessary screen resolution for this job.