Without food (with water): about 2–5 days (Jensen et al. 2013; TheVetDesk 2–4). Without water: no fixed limit for a wild mouse on moist food, but lab mice on dry food deteriorate within 24 hours (Bekkevold 2013). Without both: no direct figure — treat a day as an emergency. A pet mouse needs fresh food and water every day.
A pet mouse must have fresh food and water every day. The figures here come from lab studies and are not safe limits. A pet mouse that has gone without water, or has stopped eating, needs urgent care from an exotic-animal vet.
How long does a mouse live without food?
How long does a mouse live without food? Only about about 2–5 days, even with water. A review of fasting studies in lab mice found that some mice died after two days without food while others lasted up to five (Jensen et al. 2013), and the vet-reviewed site TheVetDesk gives 2–4 days for pet mice. Mice lose about 11% of their body weight in the first 24 hours of a fast (Jensen 2013).
That's far shorter than a rat, and the reason is size. A mouse eats roughly a tenth of its body weight every day (ICWDM) — about 3.6 g for a 30 g mouse — and has very little fat in reserve. The review links the difference partly to torpor, a short energy-saving state some mice enter when food runs out (Jensen 2013). So how long can a mouse live without food? Days, not weeks. And how long can mice survive without food safely? Not long at all: treat even 12 hours as a problem for a pet.
How long can a pet mouse go without food?
For a pet, aim for never. Mice eat many small meals, mostly at night. If your mouse hasn't eaten for 24 hours, offer food and water and call an exotic-animal vet — not eating is often the first sign of illness.
How long can mice go without water?
This depends on what the mouse is eating. Do mice need water? Wild house mice can often manage without drinking: Cornell IPM says mice "can obtain enough moisture from most food sources to remain hydrated", and ICWDM agrees that mice can get water from food, though they'll lap condensation or drips when it's there. So where do mice get water? Mostly from their food — which is why there's no fixed limit for a wild mouse with moist food.
A pet on dry pellets is different. How long can a mouse live without water? No study measured survival, but in a lab study mice without water deteriorated after 24 hours and lost more than 15% of their weight, and the researchers advised against going beyond 24 hours (Bekkevold et al. 2013). TheVetDesk says mice can potentially survive much longer without drinking because of the water in their food — but that applies to moist food, not a dry diet. Treat a pet mouse without water for a day as an emergency.
How much does a mouse eat and drink each day?
How much does a mouse eat a day? About 12 g of food per 100 g of body weight, and it drinks about 15 ml per 100 g (Wayne State University IACUC). An adult pet mouse weighs 20–40 g (Merck), so that's only a few grams of food and a few millilitres of water — but proportionally more than twice what a rat eats.
| Mouse | Food a day | Water a day |
|---|---|---|
| 20 g mouse | about 2.4 g | about 3 ml |
| 30 g mouse | about 3.6 g | about 4.5 ml |
| 40 g mouse | about 4.8 g | about 6 ml |
ICWDM's rule of thumb for house mice is about a tenth of body weight in food a day. Because the amounts are so small, a mouse can run out quickly if a bowl is knocked over or a bottle jams — check both every day.
How long can mice live in your house without food?
How long can mice live in your house without food? Only a few days — but a house rarely has no food for a mouse. One mouse uses an area just 10–30 ft across and seldom travels far for food or water (ICWDM), so crumbs, pet food, stored grain and seeds in a small area can keep it going. How long can mice live without food and water in a house? If both were truly gone, probably no more than a couple of days — but most homes have water from leaks, condensation or moist food.
Will mice leave if there is no food?
Not quickly, and not on that alone. Cornell IPM says house mice can live their entire lives indoors, and they get much of their water from food. University extension guides describe lasting control as sanitation (removing food and shelter), sealing entry points and, where needed, professional population control together. For a problem in your home, contact a licensed pest professional or your local council.
How long can mice live in walls?
Mice nest inside walls, equipment and other protected spots (Cornell IPM) and come out to feed — ICWDM says a mouse leaves and returns to its nest up to 40 times a day. A mouse sealed into a wall with no food would only survive days, but mice in walls usually have a way out to food. The typical house mouse lives 9–12 months in total (UC IPM) — see our mouse lifespan calculator for more.
Leaving a pet mouse alone: what's safe?
Can I leave my pet mouse alone? For a night, usually yes, with plenty of food and a tested water bottle. For longer, arrange a sitter. TheVetDesk advises not letting mice go without food and water for more than a day and having someone check on them at least every 2 days when you're away; daily checks are safer, because mice have so little in reserve.
- Two water sources (for example two bottles), both tested before you leave.
- Extra food in a heavy bowl, plus some scattered for foraging.
- A sitter who checks water, food and every mouse daily, and has your exotic vet's number.
- A steady room temperature out of sun and draughts.
Mouse vs rat: who survives longer without food?
Rats survive much longer without food than mice — roughly a week or more against a few days — because they are about ten times heavier and eat proportionally less.
| Mouse | Rat | |
|---|---|---|
| No food (water available) | about 2–5 days (Jensen et al. 2013) | about 6–12 days (Goodman et al. 1980) |
| No water (food available) | Lab mice deteriorate after 24 h (Bekkevold 2013); wild mice can live on moist food | 10–16 days in one study (TheVetDesk) |
| No food and no water | No direct figure; treat 24 h as an emergency | Up to about 4 days (TheVetDesk) |
| Food a day | About 12 g per 100 g body weight | About 5 g per 100 g body weight |
| Water a day | About 15 ml per 100 g | About 8–10 ml per 100 g |
For the full rat figures, see our guide to how long a rat can live without food.
How this mouse survival calculator works
Choose the situation and whether it's a pet mouse or a wild house mouse. The calculator shows the sourced range in days — never a single number — and the mouse's daily food and water needs. Where there's no survival study, it says so: for a pet mouse without water it shows the window in which lab mice became seriously dehydrated (1–2 days), and for a wild mouse with moist food it reports no fixed limit. Add the hours or days since the last food or water to get a status and a bar.
For pets, the status follows care thresholds: up to 12 hours "Within normal range — refill now", 12–24 hours "Refill now and watch closely", and from 24 hours "Urgent — see a vet now". For wild mice it says whether the time is within or beyond the sourced range. Negative times show an error. The page gives facts only — no instructions for harming animals.
Frequently asked questions
How long can a mouse live without food?
About about 2–5 days with water. Some lab mice died after two days of fasting and others lasted up to five (Jensen et al. 2013).
How long can a mouse live without water?
A wild mouse with moist food may not need to drink at all. On dry food, lab mice deteriorated within 24 hours (Bekkevold 2013) — a pet without water needs a vet urgently.
Do mice need water?
They drink when they can, but Cornell IPM says mice can get enough moisture from most foods. Pet mice on dry pellets must always have water.
How long can mice live without food and water?
No study gives a figure. Without water mice deteriorate within a day, and without food some die after two days, so treat 24 hours without both as an emergency.
How much does a mouse eat a day?
About 12 g per 100 g of body weight — about 3.6 g for a 30 g mouse (Wayne State University IACUC). ICWDM says about a tenth of body weight.
Will mice leave if there is no food?
Rarely quickly. Mice use a small area and get water from food, so lasting control needs sanitation, sealing entry points and professional help where needed.
How long can mice live in your walls?
Mice nest in walls and come out to feed. Without any food they'd survive only days, but they usually have access to food elsewhere in the house.
Can I leave my pet mouse alone for a weekend?
Only with someone checking at least daily. TheVetDesk advises not letting mice go more than a day without food and water.
Do mice survive longer without food than rats?
No — rats last longer: about about 6–12 days with water, against about 2–5 days for mice.
This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.