There is no grading scale for electronics. There is a state, and a short list, and one word that has to be earned.
The state comes first
Tested, working — you powered it on and used it. Tested, with faults — it runs and something is wrong. Say what. Untested — you did not power it on. For parts or repair — a known fault that stops normal use.
Never write "working" for a device you have not switched on. That single word is the difference between a sale and a return. Common mistakes.
Then the specifics
Screen — scratches, dead pixels, burn-in, delamination. Photograph on white and on black; different faults show on each. Battery — age, reported health, real-world life. Ports and buttons — which you tested. Body — dents, scuffs, cracked back. Repairs — screen, battery, anything opened, and by whom. Software state — signed out, removed from the account, reset.
Why cosmetic grades fail here
"Grade A" and "9/10" are retailer shorthand with no shared definition. If you use them, define them in the same breath — or skip them and describe the marks, which takes the same space and cannot be misread.
The sentence that is not about condition and matters most
"Signed out of all accounts, removed from my account, and factory reset." A device still linked to its previous owner can be unusable. Selling electronics.
Questions people ask
Is "refurbished" a grade?
Only with who did the work and what was replaced.
How do I describe an intermittent fault?
As intermittent, how often, and price for it.
Does battery health have a scale?
Where the device reports a figure, quote it and say it is the device's own.