IUPAC Naming Calculator
Generate a systematic IUPAC name for a straight-chain or lightly branched organic compound. Enter the parent chain length, saturation, any functional group suffix, and optional methyl or halogen substituents. The calculator returns the IUPAC name plus a breakdown of which root, suffix, and prefix were applied.
This IUPAC naming calculator walks through the same steps a student would use by hand: identify the parent chain, assign the suffix from the highest-priority functional group, add substituent prefixes in alphabetical order, and number to give the principal group the lowest locant. It handles parents from 1 (methane) through 20 (icosane) carbons.
What This Calculator Covers
- Alkanes, alkenes, and alkynes with a single site of unsaturation
- Alcohols, aldehydes, ketones, carboxylic acids, amines, and nitriles as the principal functional group
- One halogen substituent (fluoro, chloro, bromo, or iodo) with its locant
- Up to four methyl branches on the parent chain with their locants
Parent Stems by Carbon Count
| Carbons | Stem | Carbons | Stem |
|---|---|---|---|
| 1 | meth- | 11 | undec- |
| 2 | eth- | 12 | dodec- |
| 3 | prop- | 13 | tridec- |
| 4 | but- | 14 | tetradec- |
| 5 | pent- | 15 | pentadec- |
| 6 | hex- | 16 | hexadec- |
| 7 | hept- | 17 | heptadec- |
| 8 | oct- | 18 | octadec- |
| 9 | non- | 19 | nonadec- |
| 10 | dec- | 20 | icos- |
IUPAC Suffix Priority
The highest-priority functional group present becomes the suffix. All lower-priority groups become prefixes.
- Carboxylic acid (-oic acid)
- Ester (-oate)
- Amide (-amide)
- Nitrile (-nitrile)
- Aldehyde (-al)
- Ketone (-one)
- Alcohol (-ol)
- Amine (-amine)
- Alkene (-ene)
- Alkyne (-yne)
- Alkane (-ane)
Two Worked Examples
- Four carbons, alkane, methyl at C2: 2-methylbutane.
- Six carbons, alcohol at C2, chloro at C3: 3-chlorohexan-2-ol.
Rules for Joining the Parts
Hyphens separate letters from numbers (but-1-ene) and separate adjacent substituent blocks (3-chloro-2-methyl). They do not separate adjacent letter segments, so 2-methyl joins to hexane as 2-methylhexane. The final 'e' of -ane is dropped when followed by a vowel-starting suffix (-ol, -one, -al, -amine), which is why it becomes hexan-2-ol rather than hexaneol.
The Naming Process Used
- Pick the longest chain containing the principal functional group. That sets the parent count (1 to 20).
- Identify the highest-priority functional group. That sets the suffix.
- Number the chain so the principal group gets the lowest locant, then lowest set of substituent locants.
- List substituent prefixes alphabetically (di, tri, tetra are ignored for alphabetization).
- Assemble: {prefix}-{parent root}{connector}{locant}{suffix}.
Limitations
This IUPAC naming calculator does not cover rings, aromatics, stereochemistry (R/S, E/Z), esters, amides, or compounds with two or more different principal groups. It is ideal as a study tool or quick check for introductory organic chemistry coursework, not as a substitute for full structure-to-name software.