How many half pans does a 5ml tube fill?

A standard 5 ml tube fills roughly 2-3 half pans once you allow for drying shrinkage, which matches what artists report in practice (Jane Blundell, Winsor & Newton). A 14 ml tube fills about 7 half pans. Tubes still work out better value than buying the same colour as ready-made pans.

Why does the paint shrink?

Moist tube watercolour holds water and humectants (such as glycerin) that evaporate as the paint dries in the pan, so the cake ends up smaller than the wet fill. Factory quality-control figures (Paul Rubens, 2026) put the loss at roughly 20-25% by volume; lighter-binder brands sit lower. The remaining dry paint is denser and more concentrated, which is why this calculator defaults to retaining 78%.

How do I fill pans from tubes without cracking?

Squeeze thin layers (about 1-2 mm) and let each layer dry completely before adding the next. For a half pan plan on 3-4 layers over roughly 6-8 days; a thick single fill shrinks unevenly and cracks. Work in a dust-free area and top up any dips after the final layer has set.

What tube sizes are available?

Common watercolour tube sizes: 5 ml (standard), 8 ml (some brands), 14 ml (large), and 37 ml (studio size). Artist grade is usually 5 or 14 ml. Student grade often comes in 8 or 12 ml tubes.

Is it cheaper to buy tubes or pans?

Tubes are almost always cheaper per ml of paint. A 5 ml Winsor & Newton tube costs roughly the same as a single 1.5 ml half pan, yet — even after drying shrinkage — yields close to 2-3 half pans of usable colour. Buy your most-used colours in tubes and refill pans yourself.

ArtCalcs

Tube Volume Calculator — Tubes to Pans Conversion

Work out how many half pans a tube of watercolour paint will fill.

Tube SizeArtist-grade tubes are usually 5 ml or 14 ml; 37 ml is studio size.

Pan TypeHalf pan holds ~1.5 ml, full pan ~3 ml (varies by brand 1.5-2.5 / 3-5 ml).

Number of Tubes

How many tubes of this size you're decanting into pans.

How We Calculate This

How Tube to Pan Conversion Works

Pans filled = (Tube volume × shrinkage factor) ÷ Pan volume

Moist tube paint loses volume as its water and humectants (glycerin) evaporate in the pan. Factory quality-control figures (Paul Rubens, 2026) put this at roughly 20-25%, so the default retains 0.78 (a 22% loss). Lighter-binder colours shrink less, so the factor is adjustable. The retained volume is divided by the pan volume (1.5 ml for a half pan, 3 ml for a full pan). Fill in 3-4 thin layers, letting each dry fully, to stop the cake cracking.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.