Best Vitamin D3 Supplements 2026: Cost per Effective Dose
A tested 2,000 IU vitamin D3 costs $0.04 to $0.08 a day at Amazon prices, about $15 to $29 a year. Our pick, NatureWise D3 2000 IU, is also the cheapest. 5 of the 8 vitamin D3 products we compare are on a testing list. Paying more mostly buys a higher dose or added K2.
By Erin Rose Updated October 20, 2026 How we score
What vitamin D3 costs a day
| Product and size | A day | Per 1,000 IU | A year |
|---|---|---|---|
| NatureWise D3 2000 IU 2,000 IU a day, 360 servings, $14.44NSF/ANSI 173 | $0.04 | $0.020 | $15 |
| NatureWise D3 5000 IU 5,000 IU a day, 360 servings, $14.99NSF/ANSI 173 | $0.04 | $0.008 | $15 |
| Nature Made D3 2000 IU 2,000 IU a day, 250 servings, $19.67USP Verified | $0.08 | $0.040 | $29 |
| Thorne Vitamin D + K2 Liquid 2,000 IU a day (2 servings), 600 servings, $34.00NSF/ANSI 173 | $0.11 | $0.055 | $41 |
| Nature Made D3 + K2 5,000 IU a day, 30 servings, $12.58USP Verified | $0.43 | $0.086 | $153 |
| Viva Naturals D3 5000 IU 5,000 IU a day, 360 servings, $9.99Not on a testing list | $0.03 | $0.006 | $10 |
| NOW D3 5000 IU 5,000 IU a day, 240 servings, $9.49Not on a testing list | $0.04 | $0.008 | $14 |
| Garden of Life Vegan D3 Spray 1,000 IU a day, 125 servings, $16.62Not on a testing list | $0.12 | $0.12 | $49 |
Which list each bottle is on, and what each list checks: third-party tested vitamin D.
A 5,000 IU pill costs less per IU, but you may not need it
Higher strengths cost less per 1,000 IU, so 5,000 IU bottles look like the best deal. But 5,000 IU is above the 4,000 IU daily upper limit for adults, so take it only on a doctor’s advice. Most adults need 1,000 to 2,000 IU a day (how much to take).
Buy a bottle you will finish
At one softgel a day, a 250-count bottle lasts about 8 months and a 360-count bottle about a year. Check the date on the bottle and buy the biggest one you will finish before it.
Amazon prices move from week to week, and the cheapest bottle can change. This table updates each night; check the price on the day you buy.
You don’t need to buy anything if you already have a bottle on a testing list: finish it, then compare.
Sources
- Prices: Amazon, checked each night; last check November 6, 2026.
- IU a serving: each product’s label in the NIH Dietary Supplement Label Database.
- Testing lists: USP Verified and NSF/ANSI 173. Details and dates: third-party tested vitamin D.
- Upper limit: NIH Office of Dietary Supplements, Vitamin D fact sheet.