Urine Volume, 24-Hour
The total amount of urine you pass in 24 hours. It reflects how much fluid you take in and lose, and it is needed to read other 24-hour urine tests.
AI-verified against cited sources. Awaiting expert reviewLOINC 3167-4
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What it is
This is simply how much urine you make over a full day, measured in milliliters. It is printed on every 24-hour urine report because the other results, such as protein, creatinine or uric acid, are totals for the whole day that depend on it. How much you make depends mostly on how much you drink, and also on your kidneys and on hormones that control water balance.
Why it matters
Urine volume shows whether your fluid intake and kidney function are in a usual range. In people who form kidney stones, a low volume makes urine more concentrated and stones more likely, which is why guidelines suggest drinking enough to make about 2 to 2.5 liters a day. Very high or very low volumes can also be clues about kidney or hormone problems, so your clinician reads them with the rest of the report. The volume is only as good as the collection, because missed urine makes it look low.
If it’s low
You made less urine than usual. The most common reasons are not drinking much, sweating a lot or a collection that missed some urine. Less often it reflects dehydration or reduced kidney function. A volume under about 400 mL a day is called oliguria, and clinicians look at kidney function promptly when they see it.
Common causes
- A collection that missed urine or ran short
- Not drinking enough fluid
- Dehydration, for example from heat, vomiting or diarrhea
- Some types of chronic kidney disease
What can help
- Ask whether the collection was complete, since labs often check urine creatinine
- Ask how much fluid is right for you, especially if you form kidney stones
If it’s high
You made more urine than usual. Most often this is simply from drinking a lot or from medicines such as water pills. Less often it is linked to high blood sugar, to hormone problems that affect how the kidneys hold water, or to kidney disease. There is no single agreed cut-off for "too much", and some studies use 3 liters a day or more.
Common causes
- Drinking a lot of fluid, including caffeine or alcohol
- Water pills (diuretics)
- Poorly controlled diabetes (high blood sugar)
- Diabetes insipidus, a condition that affects the hormone or kidney response that controls water balance
- Some forms of kidney disease
What can help
- Ask whether the amount you drink is right for you, since 24-hour tests expect your usual routine
- If the volume is new or very large, ask whether blood sugar, sodium or urine concentration should be checked
Usual ranges
What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.
For adults: 800–2,000 mL/24 h. Source: MedlinePlus Medical Encyclopedia (NIH National Library of Medicine).
- Adults (this one applies)800–2,000 mL/24 h
Source: MedlinePlus Medical Encyclopedia (NIH National Library of Medicine)
What can affect your result
- How much you drink, and what (caffeine, alcohol)
- Heat, sweating and exercise
- Water pills and some other medicines
- Blood sugar control
- Kidney function and hormones that control water balance
- How completely you collected the urine
- Missed urine, spilled urine, or a collection that runs short or long makes the volume wrong. Labs often check urine creatinine to judge whether the collection was complete.
- How much you drink on the collection day sets the volume. Drink as you normally do unless your clinician says otherwise.
- Water pills (diuretics) increase urine volume (MedlinePlus). Caffeine, alcohol, heat and sweating also change it.
- Tell the lab the exact start and end times so the total can be matched to 24 hours.
A full 24-hour collection. Empty your bladder at a set time and discard that urine, then collect every urine for 24 hours, including the first urine at the same time the next morning. Keep it cold during collection. Reflects the 24 hours you collected, and changes within hours as you drink more or less.
When to talk to a clinician
Contact a clinician promptly if you are making very little urine (under about 400 mL a day) or none, especially with swelling, dizziness or confusion, or if you are passing very large amounts and feel extremely thirsty. Seek emergency care if you cannot pass urine at all or you feel faint.
Questions you could ask
- How much should I be drinking, given my history?
- Could my fluids, medicines or blood sugar explain this volume?
- Do we need to check my urine concentration or sodium?
- Was my collection complete?
- Should we look at my kidney function?
Questions people ask
Is 2 liters of urine a day the right amount?
It sits inside the usual 800–2,000 mL range. For people who form kidney stones, guidelines suggest aiming for about 2 to 2.5 liters a day, but the right goal depends on you, so ask your clinician.
What if I think I missed some urine?
Tell the lab or your clinician. A missed sample makes the volume and the other 24-hour totals look too low, and labs often check urine creatinine to see whether the collection was complete.
Should I drink extra water on collection day?
Unless your clinician says otherwise, follow your usual routine. Extra fluid raises the volume and dilutes the urine, which can change other results on the report.
Show the science and sources
Units
- 1 mL/24 h = 1 mL/24 h
- 1 mL/24 h = 0.001 L/24 h
Open the 24h Urine Volume unit converter
For clinicians and researchers
MedlinePlus gives 800–2,000 mL/day on a normal intake of about 2 L/day. StatPearls defines oliguria as under 400 mL/day or under 20 mL/h (the Acute Dialysis Quality Initiative group uses under 0.3 mL/kg/h for at least 24 hours). There is no universally accepted definition of polyuria: studies have used 3 L/24 h or more in adults and weight-based cut-offs of more than 40 or 50 mL/kg/24 h (Newell-Price, J Clin Endocrinol Metab 2025). In kidney-stone care the Brazilian Society of Nephrology (2025) lists more than 2.0–2.5 L/day (25–30 mL/kg/day) as the target, under 1.5 L/day as an attention level and under 1 L/day as an action level, and says creatinine excretion (14–20 mg/kg/day for women and 20–25 mg/kg/day for men under 50) shows whether the collection was adequate. Ng 2021 states that stone formers should keep urine output at or above 2.5 L/day because low volume is the main driver of supersaturation. Mayo requires the 24-hour volume for its supersaturation profile and reports it under LOINC 3167-4.
LOINC 3167-4 (primary), 3168-2. Specimen: urine-24h.
Sources
- Urine 24-hour volume, MedlinePlus Medical Encyclopedia (NIH National Library of Medicine)
- Brazilian Guidelines on evaluation and clinical management of Nephrolithiasis: Brazilian Society of Nephrology, Jornal Brasileiro de Nefrologia (2025)
- Medical evaluation and pharmacotherapeutical strategies in management of urolithiasis, Therapeutic Advances in Urology (2021)
- Oliguria, StatPearls Publishing (NCBI Bookshelf) (2023)
- Approach to the Patient With Suspected Hypotonic Polyuria, Journal of Clinical Endocrinology & Metabolism (2025)
- SUP24 - Supersaturation Profile, 24 Hour, Urine, Mayo Clinic Laboratories (via the testcatalog.org mirror)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.