Seiko Calculator (ref. 6138-7000) Slide Rule


  • BRAND: Seiko
  • MODEL: Slide Rule Chronograph Calculator
  • REFERENCE: 6138-7000
  • YEAR: 1970 (Estimate)
  • MOVEMENT: Manual, Cal. 6138B
  • DIAMETER CASE: 44x47mm
  • DIAL COLOR: Black
  • CASE MATERIAL: Stainless Steel
  • BEZEL MATERIAL: Stainless Steel
  • BRACELET MATERIAL: Stainless Steel (Size: 19,5cm)
  • CLASP: Folding Clasp
  • GLASS: Sapphire

In stock

Seiko Calculator 6138-7000 Slide Rule

A true collector’s item, this watch is coveted not only for its vintage appeal but also for the rarity of its reference. It was specifically designed for those who needed a slide rule on their wrist to perform mathematical calculations. The “Calculator” designation refers to the slide rule double bezel, which allows for quick and easy mathematical equations on the go.

The 7000 model is one of the rarest and most sought-after 6138s available.



  • Photos are of the watch for sale.
  • We provide a 6-month warranty on all watches!
  • All watches are fully checked by our watchmaker.
  • Watches can be picked up in a highly secured office.
  • All our shipments are insured.

We have been in this industry for over 20 years. We have experience with multiple brands such as RolexCartier, Heuer and Breitling. Payments can be made on the website and (when preferred) cash on collection. If you have any questions, do not hesitate to contact us!




Phone: 0031(0)614308004