The difference is alternate values to just two letters of the Hebrew Alphabet, but the implications for our understanding of the Bible are profound, because using the correct ciphers with a text, is like using the right key to open a locked door.
A gematria cipher is a set manner of assigning numbers to letters of the alphabet so that words can represent values.
β Beta = Beth (2)
α Alpha = Aleph (1)
γ Gamma = Gimel (3)
τ Tau = Shin (3)
δ Delta = Daleth (4)
υ Upsilon = Tav (4)
ε Epsilon = Heh (5)
Ϝ Digamma = Waw (6)
ζ Zeta = Zayin (7)
η Eta = Cheth (8)
θ Theta = Teth (9)
ι Iota = Yod (10)
κ Kappa = Kaph (20)
φ Phi = Kaph (20)
λ Lamda = Lamed (30)
μ Mu = Mem (40)
χ Chi = Mem (40)
ν Nu = Nun (50)
ψ Psi = Nun (50)
ξ Xi = Samekh (60)
ο Omicron = Ayin (70)
π Pi = Peh (80)
ω Omega = Peh (80)
ϙ Koppa = Tsade (90)
ϡ Sampi = Tsade (90)
ρ Rho = Qoph (100)
ς Sigma/Stigma = Resh (200).
• The English Gematria cipher: is the Biblical Gematria cipher transliterated to the Latin alphabet:
A=1, B=2, C=8, D=4, E=5, F=80, G=3, H=5, I=10, J=10, K=20, L=30, M=40, N=50, O=70, P=80, Q=100, R=200, S=60, T=9, U=6, V=6, W=6, X=60, Y=10, Z=7, and includes the digraphs: Sh=3, Th=4, Ch=8, Ph=80, Ts or Tz=90.
This transliteration is useful for working with Aleister Crowley's gematria, particular the 'Holy Books' series.
Using the correct numerical ciphers with occult and biblical texts is the first step towards reading their extra context.
Biblical Gematria was a practice with rules and conventions, so your next step is to learn what they are.
This is what makes Behold! The Art and Practice of Gematria unique amongst textbooks on the subject. It includes a thorough compilation of the rules and conventions of the biblical practice, so the logic of calculations can be checked. It really is a complete manual to the practice of gematria.