Paint Thinner vs. Turpentine: What's the Difference?

Both products serve the same basic function — thinning oil-based paint and varnish, and cleaning brushes and tools used with them — but they come from different sources and have real differences in odor, cost, and specific use cases worth knowing before defaulting to one or the other.

1. What turpentine actually is

Turpentine is a natural solvent distilled from pine tree resin (specifically the gum or sap of certain pine species) — it's a traditional, long-established artist's and painter's solvent, historically the standard choice before synthetic alternatives became widely available and less expensive.

2. What paint thinner (mineral spirits) actually is

"Paint thinner" most commonly refers to mineral spirits, a petroleum-distillate solvent — synthetic in origin (derived from petroleum rather than a plant source), generally less expensive than turpentine, and the more common default choice in most hardware stores today for thinning oil-based paint and general cleanup.

3. Odor — a genuine, noticeable difference

Turpentine has a distinctive, strong pine-like odor that many people find more noticeable and less pleasant during extended use than mineral spirits' odor — "odorless" mineral spirits products exist specifically as a lower-odor alternative to standard mineral spirits, addressing a common complaint that regular turpentine doesn't have an equivalent low-odor option for.

4. Performance for thinning oil-based paint

Both work effectively for thinning oil-based paint to a workable consistency and for general brush cleanup — some traditional oil painters and varnish users prefer turpentine specifically for certain fine-art applications, citing subtle differences in how it interacts with certain oil-based mediums, though for general household oil-based paint use, mineral spirits performs the thinning and cleanup job equally well for most practical purposes.

5. Cost and availability

Mineral spirits (standard paint thinner) is generally less expensive and more widely available at hardware and paint stores than pure turpentine, which is part of why it's become the more common default for general household and contractor use, with turpentine remaining more specifically associated with fine-art and traditional painting contexts.

6. Safety considerations apply to both

Both are genuinely flammable solvents deserving the same fire-safety handling covered for paint thinner generally — proper ventilation, keeping away from ignition sources, and safe disposal of any soaked rags (the same spontaneous-combustion risk applies to rags soaked in either product) apply equally to turpentine and mineral spirits; neither is inherently the "safer" option in terms of flammability.

7. Which to choose

For general household oil-based paint work and cleanup, mineral spirits (standard paint thinner) is the practical, cost-effective default. For traditional oil painting or varnish work where a specific technique or personal preference calls for turpentine's particular properties, it remains a reasonable, if pricier and stronger-smelling, alternative — the choice is largely one of use case and preference rather than one being objectively superior for every application.