---
title: "Homemade Soda Syrup Ratio Calculator | Blue Fizz Club"
description: "Soda syrup ratio made simple: 1:1 or 2:1 syrup, flavour and citric acid, how much syrup per glass of sparkling water, and the sugar in each glass."
url: https://bluefizzclub.me/homemade-soda-syrup-calculator/
---

Syrup ratio, dilution and sugar per glass

# Homemade soda syrup calculator: ratio and syrup per glass

A good starting point is a 1:1 syrup, equal weights of sugar and water, at about **1 part syrup to 7 parts sparkling water: 30 ml (1 fl oz) of syrup topped up with 220 ml (7.4 fl oz) of fizz**. That glass holds about 18.6 g of sugar, well over half the NHS's 30 g daily limit for adults and above the 10 g the US guidelines allow for a whole meal, so the calculator also shows the smallest pour that still tastes of something.

## Soda syrup ratios, explained

A syrup ratio is sugar to water **by weight**. A 1:1 "simple" syrup is half sugar; a 2:1 "rich" syrup is two-thirds sugar and pours thicker; a 1:2 "light" syrup is a third sugar. Weighing matters because a cup of sugar and a cup of water weigh different amounts: USDA FoodData Central puts a cup of granulated sugar at 200 g, while a cup of water is about 237 g.

Once dissolved, the syrup is denser than water, so a millilitre of it carries more sugar than you might guess. Using the density of sugar solutions measured by the US National Bureau of Standards, this is what each strength holds:

| Syrup | Sugar by weight | Density at 20 °C | Sugar per US tablespoon (14.8 ml) | Sugar per 30 ml (1 fl oz) |
| --- | --- | --- | --- | --- |
| Rich 2:1 | 66.7 % | 1.327 g/ml | 13.1 g | 26.5 g |
| Simple 1:1 | 50 % | 1.230 g/ml | 9.1 g | 18.4 g |
| Light 1:2 | 33.3 % | 1.143 g/ml | 5.6 g | 11.4 g |

Richer syrup is not sweeter per gram of sugar; it just packs the same sugar into less liquid. That is handy for keeping more fizz in the glass, since every millilitre of syrup is a millilitre less of cold, carbonated water. For a fizzy soda that stays lively, see the [carbonation calculator](https://bluefizzclub.me/) for the pressure your sparkling water needs.

The same 30 ml pour (the dark band) under 220 ml of sparkling water: the syrup strength sets the sugar.

## How much syrup per glass of sparkling water?

Pour the syrup first, then the cold sparkling water, and stir once. Between 15 and 30 ml of 1:1 syrup in 200 to 250 ml of fizz suits most flavours; bold ones such as ginger or winter spice carry further than delicate citrus. The calculator gives the dilution as syrup to water, so 30 ml to 220 ml shows as 1 : 7.3.

For scale, USDA FoodData Central lists regular cola at 9.94 g of sugars per 100 g, which is 36.8 g in a 12 fl oz (355 ml) can, or about 26 g per 250 ml. A 30 ml pour of 1:1 syrup in the same 250 ml glass has about 18 g.

## Flavour and acid

Warm the sugar and water together until clear, take the pan off the heat, add the flavouring and leave it to steep as it cools, then strain into a clean bottle. Zest gives fragrance without bitterness if you take only the coloured layer; thin slices of fresh ginger give more bite the longer they steep. Juice in a flavour is counted as part of the water, and its own sugar from FoodData Central is added to the total.

Citric acid gives the clean sourness that makes a soda taste like a soda rather than sweet water. Because it is set as a percentage of the syrup's weight, it scales with the batch: 1 % of a 500 g batch is 5 g. Add it after the syrup has cooled a little, stir until dissolved, and taste a diluted glass before adding more.

## Worked examples

- **Lemon soda, 1:1 syrup:** 250 g sugar, 190 g water and 60 ml lemon juice make about 406 ml of syrup at 50.3 % sugar. 30 ml per glass with 220 ml of fizz gives 18.6 g of sugar, and the batch fills 13 glasses.
- **Same syrup, capped at 10 g:** switch to low-sugar mode and the calculator pours 16 ml per glass, a 1 : 13.6 dilution. Add more zest or ginger to the syrup so the weaker glass still tastes of something.
- **Rich ginger syrup:** 250 g sugar and 125 g water with 100 g sliced ginger; 20 ml per glass with 230 ml of fizz gives 17.7 g of sugar.

## Sugar per glass against the guidance

Sugar from a syrup counts as **free sugars** for the NHS and the World Health Organization, and as **added sugars** in the US Dietary Guidelines. The NHS says adults should have no more than 30 g of free sugars a day, children aged 7 to 10 no more than 24 g, and children aged 4 to 6 no more than 19 g. The WHO recommends keeping free sugars below 10 % of energy and suggests that going below 5 %, roughly 25 g a day, brings further benefits. The Dietary Guidelines for Americans, 2025–2030, say no amount of added sugars is recommended, that one meal should contain no more than 10 g, and that sugar-sweetened drinks are best avoided.

The card shows a glass against each of those, as a guide rather than a target: they are whole-day or whole-meal figures, not allowances for one drink. The same guidelines also advise limiting low-calorie sweeteners, so the low-sugar mode here works by pouring less, not by swapping sugar for a sweetener. This is general information, not medical or dietary advice.

## Common mistakes

- **Measuring the ratio by volume.** A cup of sugar weighs less than a cup of water, so a "1:1" by cups comes out weaker than 1:1 by weight.
- **Boiling the syrup hard.** Water boils off and the syrup gets stronger than its ratio; warm it only until the sugar dissolves.
- **Forgetting the juice.** Orange juice adds sugar of its own; the calculator includes it, but a free-pour of extra juice does not.
- **Pouring fizz onto a warm syrup.** Warm liquid holds less gas, so the glass goes flat faster; keep syrup and water cold.

Making fruit syrups to keep, rather than a quick soda base? Jelly Glimmer's [jam, pectin and canning calculators](https://jellyglimmer.me/) are made for that. For cooking with the leftover syrup, try [MealWhim](https://mealwhim.me/).

## Questions

**What is the best soda syrup ratio?**

A 1:1 simple syrup, equal weights of sugar and water, is the easiest to measure and to adjust by taste. A 2:1 rich syrup packs the same sweetness into less liquid, which keeps more fizz in the glass; a 1:2 light syrup suits people who want a less sweet drink.

**How much syrup goes in a glass of sparkling water?**

Start with 30 ml (1 fl oz) of 1:1 syrup topped up with 220 ml (7.4 fl oz) of sparkling water, about 1 part syrup to 7 parts water, and adjust to taste. That glass has about 18 g of sugar; 15 ml halves it.

**How much sugar is in homemade soda compared with cola?**

USDA FoodData Central lists regular cola at 9.94 g of sugars per 100 g, about 26 g in 250 ml. A 250 ml glass made with 30 ml of 1:1 syrup has about 18 g, and with 15 ml about 9 g.

**How should I store homemade soda syrup?**

In a clean, closed bottle in the fridge. We have not found official guidance on how long a homemade syrup keeps, so we don't give a number: throw it out if it turns cloudy, smells fermented, fizzes on its own or shows any mould.

**Is homemade soda OK for children?**

Treat it like any sugary drink. The NHS says children aged 4 to 6 should have no more than 19 g of free sugars a day and children aged 7 to 10 no more than 24 g, so one strong glass can use most of a day's limit. A light syrup and a small pour keep it lower.

## Sources

- Density of sugar solutions at 20 °C (specific gravity 20°/4 °C by degrees Brix): [Bates FJ and associates, Polarimetry, Saccharimetry and the Sugars, NBS Circular 440, Table 109](https://nvlpubs.nist.gov/nistpubs/Legacy/circ/nbscircular440.pdf) (published 1942; NIST archive).
- Sugar contents and weights of granulated sugar (1 cup 200 g, 1 tsp 4.2 g, 387 kcal per 100 g), lemon, lime and orange juice, and regular cola: [USDA FoodData Central](https://fdc.nal.usda.gov/), SR Legacy items 169655, 167747, 168156, 169098 and 174852 (published April 2018; checked 5 November 2026).
- Adults no more than 30 g of free sugars a day, children 7 to 10 no more than 24 g, 4 to 6 no more than 19 g; what counts as free sugars: [NHS, Sugar: the facts](https://www.nhs.uk/live-well/eat-well/food-types/how-does-sugar-in-our-diet-affect-our-health/) (page last reviewed 19 May 2023; checked 5 November 2026).
- Free sugars below 10 % of energy, and below 5 % (roughly 25 g a day) for further benefits: [World Health Organization, news release on the Guideline: sugars intake for adults and children](https://www.who.int/news/item/04-03-2015-who-calls-on-countries-to-reduce-sugars-intake-among-adults-and-children) (published 4 March 2015).
- No amount of added sugars recommended, no more than 10 g in one meal, avoid sugar-sweetened beverages, limit non-nutritive sweeteners: [Dietary Guidelines for Americans, 2025–2030](https://cdn.realfood.gov/DGA.pdf), US Departments of Agriculture and Health and Human Services (released January 2026; checked 5 November 2026).