Base32 is a binary-to-text encoding using an alphabet of 32 characters (RFC 4648 standard: A-Z, 2-7). It is case-insensitive, avoids confusing characters, and each character represents exactly 5 bits of data.
⚠Base32 uses the RFC 4648 alphabet: A-Z followed by 2-7. Note that 0, O, 1, and I are excluded to avoid visual confusion. The mapping is: A=0, B=1, C=2, D=3, E=4, F=5, G=6, H=7, I=8, J=9, K=10, L=11, M=12, N=13, O=14, P=15, Q=16, R=17, S=18, T=19, U=20, V=21, W=22, X=23, Y=24, Z=25, 2=26, 3=27, 4=28, 5=29, 6=30, 7=31.
What Is Base32?
Base32 is a binary-to-text encoding scheme that represents binary data using an alphabet of 32 characters. The RFC 4648 standard uses A-Z and 2-7, deliberately avoiding characters that are visually similar (0/O, 1/I) to reduce human error. Each base32 character represents exactly 5 bits of binary data.
Case Insensitive
Base32 is case-insensitive. "A" and "a" are equivalent, making it suitable for case-insensitive systems like filenames and DNS records.
Place Value Expansion
Base32 to decimal: multiply each digit by 32^position. For example, 1A8₃₂ = 1×1024+10×32+8×1 = 1352₁₀.
Repeated Division by 32
Decimal to base32: repeatedly divide by 32, collect remainders, and read in reverse. Use RFC 4648 alphabet for conversion.
Practical Applications
Base32 is used in DNSSEC, Kerberos, email, file sharing, Bitcoin addresses, and any system needing case-insensitive, error-resistant encoding.
💡 Teaching Example: Convert base32 1A8₃₂ to decimal. Place value expansion: 1×32²+10×32¹+8×32⁰ = 1×1024+10×32+8×1 = 1024+320+8 = 1352₁₀. Conversely, 1352₁₀: 1352÷32=42 r8, 42÷32=1 rA, 1÷32=0 r1 → 1A8₃₂.
Applications
DNSSECKerberosEmailFile SharingCryptocurrency
Frequently Asked Questions
What is base32 encoding?▼
Base32 is a binary-to-text encoding that represents data using an alphabet of 32 characters. The RFC 4648 standard uses A-Z and 2-7, avoiding confusing characters like 0, O, 1, and I. Each base32 character represents 5 bits of binary data.
How do you convert base32 to decimal?▼
Place value expansion: multiply each base32 digit by its power of 32, then sum. For example, 1A8₃₂ = 1×32²+10×32¹+8×32⁰ = 1×1024+10×32+8×1 = 1024+320+8 = 1352₁₀.
How do you convert decimal to base32?▼
Repeated division by 32: repeatedly divide by 32, collecting remainders. Use the RFC 4648 alphabet (A-Z, 2-7). Read remainders in reverse. For example, 1352÷32=42 r8, 42÷32=1 rA, 1÷32=0 r1 → 1A8₃₂.
What are common uses of base32?▼
Base32 is used in DNSSEC, Kerberos, email, and file sharing. It is case-insensitive, avoids visually similar characters, and works well in systems with case-insensitive storage or display. Bitcoin uses base32 for some addresses.
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