Hosting is easier when you can do the wine maths in your head, so here it is.
A standard 750ml bottle of wine gives you six 125ml glasses, just over four 175ml glasses, or three 250ml glasses. In the US, where a standard pour is 5 fluid ounces (about 148ml), a bottle gives you about five glasses. Everything else in this guide, from magnums to party planning, comes from those four numbers.
I build Sommo, and the most common hosting question I hear is not “which wine?” but “how much?”. Get the quantity right and you can spend your attention on the good part: what to pour.
How many glasses are in a standard bottle of wine?
A standard wine bottle holds 750ml, also written 75cl. The number of glasses depends entirely on the size of the pour.
| Pour | Glasses per 750ml bottle |
|---|---|
| 125ml (UK small) | 6 |
| 148ml (US 5 fl oz) | about 5 |
| 175ml (UK medium) | 4, with a little left |
| 250ml (UK large) | 3 |
At home, nobody measures, and most people pour more generously than they think. If you are using big glasses, count on the 175ml line rather than the 125ml line.
What size is a glass of wine in the UK?
UK weights and measures law says that if a pub, bar or restaurant sells still wine by the glass, it must be sold in 125ml, 175ml or multiples of either. In practice that gives you three common sizes on a menu: small (125ml), medium (175ml) and large (250ml).
Two details trip people up:
- Sparkling wine has no specified glass size. The same GOV.UK guidance sets measures for still wine but not for sparkling, so a glass of Prosecco can be any size the venue chooses.
- Fortified wine is smaller. Port, sherry and similar wines are sold in 50ml or 70ml measures, or multiples of those.
How many glasses of wine are in a bottle in the US?
In the US, the reference point is the standard drink. The National Institute on Alcohol Abuse and Alcoholism defines a standard drink as 14 grams of pure alcohol, which it equates to 5 fluid ounces of wine at about 12% alcohol, or 3 to 4 fluid ounces of fortified wine.
A 750ml bottle holds about 25.4 fluid ounces, so it gives you just over five standard 5 oz pours. Restaurant pours vary, but five glasses a bottle is the number American hosts plan around.
How many glasses do bigger and smaller bottles give?
Bottle sizes scale neatly, because almost all of them are multiples or fractions of 750ml. My wine bottle sizes guide covers the full range, but these are the ones you will actually meet:
| Bottle | Volume | 125ml glasses | 175ml glasses |
|---|---|---|---|
| Piccolo or split | 187.5ml | 1 and a half | 1 |
| Half bottle | 375ml | 3 | 2, with a little left |
| Standard | 750ml | 6 | 4, with a little left |
| Magnum | 1.5 litres | 12 | about 8 |
| Double magnum | 3 litres | 24 | about 17 |
Half bottles are underrated for a weeknight or a table of two who want different colours. I have made the case for them in are half bottles of wine worth it?. Magnums are the opposite: one big bottle that looks generous on a long table and holds two bottles’ worth in one go.
How much wine do you need for a party?
This is where the glasses number earns its keep. I use a simple method:
- Count drinking guests, not total guests. Leave out drivers, children and anyone who has told you they are not drinking.
- Estimate glasses per guest. For a dinner, I plan on about one glass per guest per course with wine. For a drinks party, I plan on a glass an hour per guest, a little more at the start.
- Divide by glasses per bottle. Use five or six for normal pours, four if your glasses are large.
- Round up and add one. Running out is worse than having a bottle left for tomorrow.
For example, eight drinking guests at a three course dinner, at a glass per course, is 24 glasses. At five glasses a bottle, that is just under five bottles. Round up to six and you are covered.
Those are my planning assumptions, not rules, and your crowd may drink more or less. If you would rather not do the sums, our free wine party calculator does them for you, and my longer guide on how much wine to buy for a party covers mixing red, white and fizz.
How many bottles do you need for Thanksgiving or Christmas?
Big holiday meals are longer than normal dinners, often with fizz on arrival, two wines with the main course and something sweet at the end. Plan by course:
- On arrival: one glass of fizz per guest. At six glasses a bottle, a bottle covers six people.
- The main meal: two glasses per guest across red and white.
- Dessert or cheese: a small pour of something sweet or fortified. A 750ml bottle of port at 50ml pours covers fifteen.
For a table of ten, that is roughly two bottles of fizz, four bottles of still wine and one bottle of port, plus one spare. For what to actually pour, see my guides to wine for Thanksgiving and wine for Christmas.
How many units are in a glass of wine?
It is worth knowing what those glasses add up to. The NHS gives 1.5 units for a 125ml glass, 2.1 units for a 175ml glass and 3 units for a 250ml glass, all at 12% alcohol. Stronger wines carry more. If you are planning a long evening, offering water and a lower alcohol option is good hosting, not fussiness.
How does Sommo help you plan the wine?
Quantity is the easy part. Choosing bottles that suit your guests, and each other, is where I find Sommo genuinely better than anything else I have used.
Scan what you already have. Point your camera at a label and Sommo identifies the wine and gives you grapes, region, tasting notes, food pairings and serving temperature. A label scan takes about 10 seconds, so checking six bottles before guests arrive takes about a minute.
Get picks shaped by your taste. Sommo learns from the wines you’ve rated, so its suggestions are shaped by what you actually enjoy, not a generic list. With Premium, Ask Sommo picks from the bottles you own for the meal you are cooking.
Remember what worked. Save the evening’s bottles to your wine journal and rate them in a tap. Next time you host, you know exactly which bottle disappeared first.
All of this runs on proprietary wine-tuned AI grounded in a hand-maintained wine library. The free tier gives you 5 lifetime AI scans per device, shared across label, menu and shelf scans, plus the journal and 30 days of journal history. Premium unlocks unlimited scans, lifetime history, Taste DNA, AI tasting feedback and Tasting Mode for $4.99 a month or $29.99 a year in the US; prices vary by country and store. Sommo runs on iPhone, iPad, Android, HarmonyOS and the web.
Download Sommo and plan your next party’s wine.
The bottom line
A 750ml bottle is six small glasses, four medium glasses, three large glasses or about five US pours. A magnum doubles that, a half bottle halves it, and fortified wine stretches to ten or fifteen pours. Count drinking guests, multiply by glasses, divide by glasses per bottle and buy one more than you think. Then spend the time you saved choosing wines worth pouring.
