What are the standard sugar syrup concentrations?

This calculator uses the general simple-syrup ratios by weight: light syrup (1 part sugar to 3 parts water, ~25% sugar), medium syrup (1:2, ~33% sugar), and heavy syrup (1:1, ~50% sugar). Note that home-canning bodies (such as the NCHFP) grade fruit-canning syrups differently, by percentage of sugar in the finished syrup: very light 10%, light 20%, medium 30%, heavy 40% and very heavy 50%. If you are following a specific canning recipe, match the % sugar it specifies rather than the cocktail-style ratio.

What is each syrup concentration used for?

Light syrup is used for poaching delicate fruits, iced tea, and lighter cocktails. Medium syrup is the most versatile, used for bottling fruit, cocktails, and moistening cakes. Heavy syrup (simple syrup 1:1) is used for strong cocktails, candy-making, and packing tart or sour fruit.

How do I make sugar syrup?

Combine sugar and water in a saucepan. Heat gently, stirring until the sugar fully dissolves. Do not boil until the sugar is dissolved, or it may crystallise. Once dissolved, bring to a brief boil, then cool. Store in a clean, sterilised bottle or jar in the refrigerator.

How long does sugar syrup keep?

Store all of these syrups in the refrigerator. Light syrup keeps about 1-2 weeks, medium syrup about 2-3 weeks, and heavy (1:1) syrup about 3-4 weeks (roughly a month) refrigerated. A 1:1 syrup is only ~50% sugar, so it is NOT shelf-stable at room temperature and will ferment or grow mould if left out. True room-temperature shelf stability needs around 65-67% sugar (a 2:1 rich syrup or higher). When in doubt, refrigerate, and discard any syrup that smells off, looks cloudy, or shows mould.

Does sugar syrup increase in volume when sugar dissolves?

Yes, adding sugar to water increases the total volume because sugar occupies space when dissolved. Each gram of sugar adds approximately 0.6ml of volume. This calculator accounts for this, so the sugar and water quantities will produce your target volume of syrup.

Syrup Concentration Calculator — Free Online Tool

How We Calculate This

This calculator works backwards from your target syrup volume to determine the sugar and water quantities needed. It accounts for the volume increase that occurs when sugar dissolves in water (approximately 0.6ml per gram of sugar).

Concentrations (sugar:water by weight)

Light: 1:3 (~25% sugar)
Medium: 1:2 (~33% sugar)
Heavy: 1:1 (~50% sugar)

These are the general simple-syrup ratios. Home-canning bodies such as the NCHFP grade fruit-canning syrups by % sugar in the finished syrup instead (very light 10%, light 20%, medium 30%, heavy 40%, very heavy 50%) — if you are following a canning recipe, match the % sugar it specifies.

Volume Calculation

Sugar adds ~0.6ml per gram when dissolved
Water volume + (sugar weight x 0.6) = target volume

Storage & food safety

Keep all of these syrups refrigerated in a clean, sterilised container.
Light keeps ~1-2 weeks, medium ~2-3 weeks, heavy (1:1) ~3-4 weeks refrigerated.
A 1:1 syrup is only ~50% sugar — it is NOT shelf-stable at room temperature and will ferment or mould if left out.
Room-temperature stability needs ~65-67% sugar (a 2:1 rich syrup). Discard any syrup that smells off, turns cloudy, or shows mould.

Frequently Asked Questions

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Last updated: February 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.