Every year I tell myself I've got Christmas dinner figured out. And every year, somewhere around December 22nd, I'm standing in the middle of the grocery store doing math on my phone, trying to remember whether a 12-pound ham feeds twelve people or twenty.
Here's the thing. Christmas dinner isn't one dish you can eyeball. It's a main, five sides, a gravy situation, dessert, and something warm to drink — and every one of those has its own number. Get one wrong and you're either making an emergency run on Christmas Eve or eating mashed potatoes until New Year's.
So I did the math for all of it. Below are three charts covering everything on a Christmas table, from 6 guests to 30. Find your number, write your list, be done.
Quick Answer
For a standard Christmas dinner, these are my starting portions per adult — before the safety buffer used in the charts:
- ¾ lb bone-in ham (or ½ lb boneless, or 1 lb prime rib, or 1¼ lb whole turkey)
- ½ lb mashed potatoes (raw weight — that's about 1 cup mashed)
- ⅓ cup gravy
- 1½ dinner rolls
- ½ cup green bean casserole
- ¼ cup cranberry sauce
- 1 slice of pie
The charts below add the safety buffer and round up to practical shopping amounts, so you don't need to add anything yourself.
For 12 adults, that's a 10 lb bone-in ham, 6¾ lb of potatoes, 5 cups of gravy, 20 rolls, and 2 pies.
Kids under 12 eat about half an adult portion of most things — the charts below have the exceptions.
Why Christmas Dinner Math Is Different
If you've hosted Thanksgiving, you'd think Christmas would be the same drill. It isn't, quite.
Thanksgiving is a turkey and a fixed lineup. Christmas is wide open — ham at one house, prime rib at another, turkey at a third, and some families serve two mains to accommodate different preferences. That single difference throws off every amount downstream, because the main dish is what sets how much of everything else people take.
The other difference is timing. Christmas dinner usually lands in the middle of a day that already had a breakfast, a present-opening, and probably a tin of cookies making the rounds since ten in the morning. People come to the table less hungry than they do on Thanksgiving. Not by a lot — but enough that the "one of several sides" portion is the right one to plan on, not the generous one.
And then there's the leftover question, which is genuinely different. Thanksgiving leftovers are a tradition people plan for. Christmas leftovers compete with a fridge that's already full of appetizers, a cheese board, and half a trifle. Plan for fewer.
The Charts
Everything below assumes adults, and every number already includes a safety buffer — so what you see is what you buy, not a starting point you have to pad yourself. I've done that padding for you, because I know nobody wants to do percentage math in a parking lot.
The Main
| Guests | Bone-in ham¾ lb each | Boneless ham½ lb each | Prime rib1 lb each | Whole turkey1¼ lb each |
|---|---|---|---|---|
| 6 | 5 lb | 3.5 lb | 7 lb3 ribs | 9 lb10–12 lb bird |
| 10 | 8.5 lb | 5.5 lb | 11 lb5 ribs | 14 lb12–14 lb bird |
| 12 | 10 lb | 7 lb | 13.5 lb6 ribs | 17 lb16–18 lb bird |
| 15 | 12.5 lb | 8.5 lb | 16.5 lb8 ribs · 2 roasts | 21 lb20–22 lb bird |
| 20 | 16.5 lb | 11 lb | 22 lb10 ribs · 2 roasts | 28 lbtwo 14 lb birds |
| 30 | 25 lb | 16.5 lb | 33 lb15 ribs · 3 roasts | 42 lbtwo 22 lb birds |
Prime rib shown at the standard dinner portion. A single standing rib roast tops out at 7 bones, which is why bigger counts need two or three roasts.
Full details: ham · prime rib · turkey
The first Christmas I hosted on my own, I stood at the meat counter for a solid ten minutes trying to decide between two hams, and then bought the bigger one because I panicked. Here's what I should have known.
Bone-in versus boneless trips people up more than anything else on this list. A bone-in ham looks like the bigger buy, and it is — but roughly a quarter of that weight is bone and skin, which is exactly why you buy more of it. You end up with the same amount of ham on plates either way. I prefer bone-in for flavor, and it gives you a soup bone; boneless slices cleanly and has very little waste. Neither is wrong. If you want to run your own numbers — different portion sizes, kids in the mix — the ham calculator does it in one screen.
If you're doing two mains because of a split crowd, don't buy full amounts of both. That's how people end up with forty pounds of protein for twenty guests. Figure your total from the chart, then divide it between the two — weighted toward whichever one you think most people will reach for.
A full standing rib roast is typically seven ribs, so once your crowd gets much past about 15 people, you're usually looking at two roasts rather than one enormous one. They cook more evenly anyway. The prime rib calculator works out the rib count and tells you when you've crossed into two-roast territory.
The Sides
| Guests | Mashed potatoes½ lb each | Gravy⅓ cup each | Dinner rolls1½ each | Green bean casserole½ cup each | Cranberry sauce¼ cup each |
|---|---|---|---|---|---|
| 6 | 3.5 lb | 3 cups | 10 | 3.3 cups | 1.65 cups2 cans |
| 10 | 5.5 lb | 4 cups | 17 | 5.5 cups | 2.75 cups2 cans |
| 12 | 6.75 lb | 5 cups | 20 | 6.6 cups | 3.3 cups3 cans |
| 15 | 8.25 lb | 6 cups | 25 | 8.25 cups | 4.13 cups3 cans |
| 20 | 11 lb | 8 cups | 33 | 11 cups | 5.5 cups4 cans |
| 30 | 16.5 lb | 12 cups | 50 | 16.5 cups | 8.25 cups6 cans |
Gravy carries a 15% buffer instead of 10%, because gravy is the one thing people always want more of. Potatoes are raw pounds — as a rough estimate 1 lb raw makes around 2 cups mashed, though finished volume varies with the potatoes and what you add. Cranberry cans are 14 oz.
Full details: mashed potatoes · gravy · rolls · green bean casserole · cranberry sauce
Sides are where I've gotten it wrong the most times, usually in the same direction. I underbuy potatoes and overbuy everything green.
The mashed potato number is raw weight, which is the one thing I'd double-check before you shop. As a rough kitchen estimate, 1 pound of raw potatoes makes around 2 cups mashed, but finished volume varies depending on the potatoes and how you prepare them — so 11 pounds for 20 guests sounds enormous right up until it cooks down. If you're doing a potato bar instead of a scoop on the plate, the mashed potato calculator has a setting for that, and the amount goes up more than you'd think.
Gravy is the one I overbuy. It carries a bigger buffer than everything else on this page for a reason: people tend to use more than expected, it costs relatively little to make extra, and running out of it makes every other dish feel a little drier. I've never regretted having extra gravy. The gravy calculator also gives you the flour and butter for the roux, which is the part I can never remember.
Rolls are where the pack sizes fight you. Rhodes frozen comes 36 to a bag, King's Hawaiian 12 to a pack — so you'll almost always be buying more than you need. That's fine. Rolls freeze. The dinner roll calculator will tell you how many bags to grab and how many spare rolls you'll end up with.
Dessert and Drinks
| Guests | Pie1 slice each | Cookies3.15 each | Hot chocolate1 cup each | Eggnog6 oz each | Fudge2 pieces each |
|---|---|---|---|---|---|
| 6 | 1 pie7 slices | 242 dozen | 7 cups2 qt milk | 40 oz1¼ qt | 141 batch |
| 10 | 2 pies11 slices | 423½ dozen | 11 cups3 qt milk | 66 oz2 qt | 221 batch |
| 12 | 2 pies14 slices | 484 dozen | 14 cups1 gal milk | 80 oz2½ qt | 271 batch |
| 15 | 3 pies17 slices | 605 dozen | 17 cups5 qt milk | 99 oz3 qt | 331 batch |
| 20 | 3 pies22 slices | 786½ dozen | 22 cups1½ gal milk | 132 oz4 qt | 441 batch |
| 30 | 5 pies33 slices | 1149½ dozen | 33 cups2¼ gal milk | 198 oz6 qt | 661 batch |
Cookies carry a 15% buffer and work out to 3.15 per adult — that's the main-dessert rate of 3.5, times 0.9 for a mostly-adult crowd. Totals then round up to the nearest half dozen, which is why 73 becomes 78. Set the calculator to "mostly adults" and you'll see these numbers. Pie carries 10%, is 9-inch, and is cut 8 slices. One fudge batch is a 9×13 pan cut 7 × 12, which is 84 pieces — so one batch covers every count on this chart.
Full details: pie · cookies · hot chocolate · eggnog · fudge
Dessert is the part I always over-plan, because by late December there's already a tin of something on every surface in my house.
The pie numbers assume dessert comes after a full dinner, which means one slice per person, not the hungrier portion you'd plan for a dessert-only party. A 9-inch pie cut into 8 is the standard here. Serving several kinds of pie so people can sample? The pie slice calculator handles that properly — more varieties means thinner slices, not more pie.
One thing that surprises people: a single batch of fudge covers every guest count on this chart. A 9×13 pan cut 7 by 12 gives you 84 pieces. At two pieces a guest, that's enough for 30 people with plenty left for boxes. Fudge is the best effort-to-output ratio on the whole dessert table, which is why it's the thing I make first every December — and the fudge calculator will work out gift boxes alongside your dessert table if you're making both.
If you're putting out cookies and pie and fudge, you can shade all three down a little. The chart treats each as if it's carrying the dessert table alone, so the cookie calculator is worth a minute if cookies are doing real work at your party.
A Real Example: 20 Adults and 6 Kids
This is the most common Christmas dinner I get asked about — a big family gathering, bone-in ham, served buffet style. Here's the whole list.
| What | How much | Why |
|---|---|---|
| Bone-in ham | 19 lb | 20 × ¾ lb + 6 kids at half, then +10% |
| Mashed potatoes | 12¾ lb raw | Roughly 25 cups mashed |
| Gravy | 10 cups | Kids counted at a flat ¼ cup |
| Dinner rolls | 38 rolls | 2 bags of Rhodes |
| Green bean casserole | 12.65 cups | Two 9×13 pans |
| Cranberry sauce | 6⅓ cups | 5 cans |
| Pie | 4 pies | 26 slices needed |
| Cookies | 9 dozen | 26 × 3.5, mixed crowd, then +15% |
| Hot chocolate | 29 cups | Buy 2 gallons of milk |
| Eggnog | 152 oz | About 4¾ quarts |
| Fudge | 1 batch | 58 pieces needed, 84 made |
Every figure above already includes that dish's safety buffer, same as the charts — so this is the shopping list, not a starting point.
Notice the ham went to 19 pounds, not 20 — the six kids only added about 2¼ pounds between them. That's the piece people get wrong in both directions. Kids don't eat nothing, but they don't eat like adults either, and for an expensive main that gap is worth a few dollars.
Troubleshooting
"I have no idea how many people are actually coming." Plan for your confirmed count plus two. Not plus ten. The buffer built into these numbers already gives you some breathing room, and over-planning for a maybe is how you end up with a fridge you can't close.
"Half my guests are teenagers." I've fed enough teenagers to know: count them as adults in every column. If your crowd skews really young and hungry, bump the main and the rolls by about a quarter and don't think about it again.
"I'm doing this buffet style, not plated." The chart amounts work for either. What changes is presentation — put out part of the main at first and refill as needed, so it stays fresh and the table never looks picked over.
"I already have appetizers out." If you're serving substantial appetizers before dinner, I usually trim the side quantities by about 10%. I leave the main at the standard amount because I'd rather have a little extra ham than run short.
"My oven can't fit all of this." Ask me how I know. This is the real Christmas problem, not the quantities — two 9×13 pans of casserole plus a ham plus rolls is more oven than most of us have. Make the casserole and cranberry ahead, warm the rolls last while the main rests, and lean on the slow cooker for potatoes. Mashed potatoes also hold well in a slow cooker on WARM — just make sure they stay at 140°F or hotter while they're being held.
FAQ
How much ham do I need for 20 people? About 16.5 pounds bone-in, or 11 pounds boneless. Bone-in looks like more because roughly a quarter of that weight is bone — you end up with the same ham on plates either way.
How much food do I need for Christmas dinner for 12? A 10 lb bone-in ham, 6¾ lb of raw potatoes, 5 cups of gravy, 20 rolls, 6.6 cups of green bean casserole, 3.3 cups of cranberry sauce, and 2 pies. That's the full lineup for 12 adults.
Should I make one big main or two? One, unless you have a real dietary split. Two mains means two things to time, two things to carve, and a much higher chance of leftovers you didn't want. If you do need both, work out your total from the chart and divide it between them rather than doubling.
How far ahead can I make Christmas dinner sides? Cranberry sauce up to a week. Green bean casserole two days, assembled but with the onions held back until the last five minutes of baking. Mashed potatoes the day before, reheated covered at 350°F. Gravy freezes. Rolls can be baked ahead and warmed.
Do kids really eat half an adult portion? For most things, roughly — but it varies by dish, and the chart footnotes have the specifics. Gravy and eggnog use a flat amount per child instead of a fraction, and nobody has ever seen a kid take half a cup of hot chocolate.
How much should I plan for leftovers? The amounts here already include a buffer, so you'll have some. If you want real leftovers — sandwiches for days — add about 25% to the main only. Adding it across every dish is how you end up throwing food away in January.
Final Thoughts
The whole point of writing the numbers down is that you only have to think about them once. Print the charts, or screenshot the one you need, and then spend the rest of December on the parts that actually matter — who's sitting where, whether the good tablecloth got washed, and remembering to take the fudge out of the freezer.
Trust me on this: nobody at your table is counting rolls. But you'll feel a whole lot better knowing there are enough.
And if you're hosting something bigger than dinner this season — a party, an open house, a whole spread of appetizers — the full party food planning guide covers the rest of the table.
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